Download Anna University B-Tech ME 5th Sem Thermal Engineering TE Lab Manual Question Paper

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DEPARTMENT OF
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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
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Section : _______________________________________

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LABORATORY MANUAL

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DEPARTMENT OF
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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
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Section : _______________________________________

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LABORATORY MANUAL
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DEPARTMENT OF
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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL

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2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

--- Content provided by FirstRanker.com ---

? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels

--- Content provided by FirstRanker.com ---

? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION

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MISSION
VISION
MISSION
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DEPARTMENT OF
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ME6512 ? THERMAL ENGINEERING LABORATORY

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Name : _______________________________________
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Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

--- Content provided by FirstRanker.com ---

? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart

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and soul


DEPARTMENT OF MECHANICAL ENGINEERING

--- Content provided by FirstRanker.com ---

Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

--- Content provided by FirstRanker.com ---

To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

VISION
MISSION

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VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence

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To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design

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products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies

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5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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FirstRanker.com - FirstRanker's Choice

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?

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DEPARTMENT OF
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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL

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2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

--- Content provided by FirstRanker.com ---

? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels

--- Content provided by FirstRanker.com ---

? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul


DEPARTMENT OF MECHANICAL ENGINEERING

--- Content provided by FirstRanker.com ---

Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

--- Content provided by FirstRanker.com ---

To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

VISION

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MISSION
VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals

--- Content provided by FirstRanker.com ---

2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which

--- Content provided by FirstRanker.com ---

enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt

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and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able

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1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution

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5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both

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verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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FirstRanker.com - FirstRanker's Choice
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DEPARTMENT OF
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ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

--- Content provided by FirstRanker.com ---

? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

--- Content provided by FirstRanker.com ---

DEPARTMENT OF MECHANICAL ENGINEERING

--- Content provided by FirstRanker.com ---

Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

--- Content provided by FirstRanker.com ---

To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

VISION
MISSION
VISION

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MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

--- Content provided by FirstRanker.com ---

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex

--- Content provided by FirstRanker.com ---

software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills

--- Content provided by FirstRanker.com ---

4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning

--- Content provided by FirstRanker.com ---

To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the

--- Content provided by FirstRanker.com ---

career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society

--- Content provided by FirstRanker.com ---

7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with

--- Content provided by FirstRanker.com ---

coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:

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HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube

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5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface

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10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes

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13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.

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4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system

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13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES

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FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________

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Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

is committed to provide highly disciplined, conscientious and

--- Content provided by FirstRanker.com ---

enterprising professionals conforming to global standards through value based quality education and training.



? To provide competent technical manpower capable of meeting requirements of the industry

--- Content provided by FirstRanker.com ---

? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

--- Content provided by FirstRanker.com ---

DEPARTMENT OF MECHANICAL ENGINEERING



Rendering the services to the global needs of engineering industries by educating students to become

--- Content provided by FirstRanker.com ---

professionally sound mechanical engineers of excellent caliber



To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on

--- Content provided by FirstRanker.com ---

experience and to inculcate the spirit of moral values and ethics to serve the society

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

VISION
MISSION
VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould

--- Content provided by FirstRanker.com ---

them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth

--- Content provided by FirstRanker.com ---

To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up

--- Content provided by FirstRanker.com ---

their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME OUTCOMES (POs)

--- Content provided by FirstRanker.com ---

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications

--- Content provided by FirstRanker.com ---

4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability

--- Content provided by FirstRanker.com ---

8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills

--- Content provided by FirstRanker.com ---

11. To develop and manage projects in multidisciplinary environments

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

ME6512 ? THERMAL ENGINEERING LABORATORY ? II



? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the

--- Content provided by FirstRanker.com ---

performance of refrigeration cycle / components

LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus

--- Content provided by FirstRanker.com ---

2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder

--- Content provided by FirstRanker.com ---

7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

--- Content provided by FirstRanker.com ---

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System

--- Content provided by FirstRanker.com ---

15. Performance test in a fluidized Bed Cooling Tower



1. Able to find out the thermal conductivity of various materials.

--- Content provided by FirstRanker.com ---

2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials

--- Content provided by FirstRanker.com ---

6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.

--- Content provided by FirstRanker.com ---

11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures

--- Content provided by FirstRanker.com ---

14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

--- Content provided by FirstRanker.com ---

COURSE OBJECTIVES
COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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CONTENTS


Sl.No.
Name of the experiment

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Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe

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apparatus
11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder

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15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS

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6
Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39

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9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58

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13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS

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16 Air conditioning test rig 75
PROJECT WORK 81
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?

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DEPARTMENT OF
MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

--- Content provided by FirstRanker.com ---

V SEMESTER - R 2013

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

--- Content provided by FirstRanker.com ---

LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

--- Content provided by FirstRanker.com ---

? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

--- Content provided by FirstRanker.com ---

DEPARTMENT OF MECHANICAL ENGINEERING

--- Content provided by FirstRanker.com ---

Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

--- Content provided by FirstRanker.com ---

To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

VISION
MISSION
VISION

--- Content provided by FirstRanker.com ---

MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

--- Content provided by FirstRanker.com ---

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex

--- Content provided by FirstRanker.com ---

software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills

--- Content provided by FirstRanker.com ---

4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning

--- Content provided by FirstRanker.com ---

To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the

--- Content provided by FirstRanker.com ---

career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society

--- Content provided by FirstRanker.com ---

7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with

--- Content provided by FirstRanker.com ---

coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

--- Content provided by FirstRanker.com ---

? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:

--- Content provided by FirstRanker.com ---

HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube

--- Content provided by FirstRanker.com ---

5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface

--- Content provided by FirstRanker.com ---

10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes

--- Content provided by FirstRanker.com ---

13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

--- Content provided by FirstRanker.com ---

1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.

--- Content provided by FirstRanker.com ---

4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

--- Content provided by FirstRanker.com ---

9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system

--- Content provided by FirstRanker.com ---

13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

--- Content provided by FirstRanker.com ---

COURSE OBJECTIVES
COURSE OUTCOMES

--- Content provided by FirstRanker.com ---

7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

--- Content provided by FirstRanker.com ---

Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6

--- Content provided by FirstRanker.com ---

2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3

--- Content provided by FirstRanker.com ---

Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5

--- Content provided by FirstRanker.com ---

Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7

--- Content provided by FirstRanker.com ---

Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS

--- Content provided by FirstRanker.com ---

11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68

--- Content provided by FirstRanker.com ---

15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

--- Content provided by FirstRanker.com ---

8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT

--- Content provided by FirstRanker.com ---

USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method

--- Content provided by FirstRanker.com ---

Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

--- Content provided by FirstRanker.com ---

Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate

--- Content provided by FirstRanker.com ---

assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The

--- Content provided by FirstRanker.com ---

heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:

--- Content provided by FirstRanker.com ---

1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

--- Content provided by FirstRanker.com ---

cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2

--- Content provided by FirstRanker.com ---

Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.
FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

?

--- Content provided by FirstRanker.com ---

DEPARTMENT OF
MECHANICAL ENGINEERING

--- Content provided by FirstRanker.com ---

ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

--- Content provided by FirstRanker.com ---

LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

--- Content provided by FirstRanker.com ---

? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart

--- Content provided by FirstRanker.com ---

and soul


DEPARTMENT OF MECHANICAL ENGINEERING

--- Content provided by FirstRanker.com ---

Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

--- Content provided by FirstRanker.com ---

To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

VISION
MISSION

--- Content provided by FirstRanker.com ---

VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

--- Content provided by FirstRanker.com ---

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence

--- Content provided by FirstRanker.com ---

To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design

--- Content provided by FirstRanker.com ---

products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies

--- Content provided by FirstRanker.com ---

5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering

--- Content provided by FirstRanker.com ---

2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools

--- Content provided by FirstRanker.com ---

6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms

--- Content provided by FirstRanker.com ---

9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

--- Content provided by FirstRanker.com ---

? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

--- Content provided by FirstRanker.com ---

LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder

--- Content provided by FirstRanker.com ---

4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant

--- Content provided by FirstRanker.com ---

9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system

--- Content provided by FirstRanker.com ---

12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

--- Content provided by FirstRanker.com ---

1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection

--- Content provided by FirstRanker.com ---

experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

--- Content provided by FirstRanker.com ---

8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.

--- Content provided by FirstRanker.com ---

12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC

--- Content provided by FirstRanker.com ---

Boiler.



COURSE OBJECTIVES

--- Content provided by FirstRanker.com ---

COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

--- Content provided by FirstRanker.com ---

Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS

--- Content provided by FirstRanker.com ---

1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11

--- Content provided by FirstRanker.com ---

3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21

--- Content provided by FirstRanker.com ---

5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31

--- Content provided by FirstRanker.com ---

7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47

--- Content provided by FirstRanker.com ---

CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14

--- Content provided by FirstRanker.com ---

Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

--- Content provided by FirstRanker.com ---

8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

--- Content provided by FirstRanker.com ---

THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate

--- Content provided by FirstRanker.com ---

method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

--- Content provided by FirstRanker.com ---

(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters

--- Content provided by FirstRanker.com ---

together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples

--- Content provided by FirstRanker.com ---

No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

--- Content provided by FirstRanker.com ---

Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2

--- Content provided by FirstRanker.com ---

(10 + x)

cm
2

--- Content provided by FirstRanker.com ---

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

--- Content provided by FirstRanker.com ---

9 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help

--- Content provided by FirstRanker.com ---

of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:

--- Content provided by FirstRanker.com ---

1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm

--- Content provided by FirstRanker.com ---

6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100

--- Content provided by FirstRanker.com ---

0
C
9. Maximum temperature of the hot plate = 170
0
C

--- Content provided by FirstRanker.com ---

10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V

--- Content provided by FirstRanker.com ---

15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0

--- Content provided by FirstRanker.com ---

C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

--- Content provided by FirstRanker.com ---

FirstRanker.com - FirstRanker's Choice

--- Content provided by FirstRanker.com ---

1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

--- Content provided by FirstRanker.com ---

DEPARTMENT OF
MECHANICAL ENGINEERING

--- Content provided by FirstRanker.com ---

ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

--- Content provided by FirstRanker.com ---

LABORATORY MANUAL

--- Content provided by FirstRanker.com ---

2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

--- Content provided by FirstRanker.com ---

? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels

--- Content provided by FirstRanker.com ---

? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul


DEPARTMENT OF MECHANICAL ENGINEERING

--- Content provided by FirstRanker.com ---

Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

--- Content provided by FirstRanker.com ---

To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

VISION

--- Content provided by FirstRanker.com ---

MISSION
VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals

--- Content provided by FirstRanker.com ---

2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which

--- Content provided by FirstRanker.com ---

enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt

--- Content provided by FirstRanker.com ---

and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able

--- Content provided by FirstRanker.com ---

1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution

--- Content provided by FirstRanker.com ---

5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both

--- Content provided by FirstRanker.com ---

verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

--- Content provided by FirstRanker.com ---

? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

--- Content provided by FirstRanker.com ---

LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus

--- Content provided by FirstRanker.com ---

3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)

--- Content provided by FirstRanker.com ---

8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:

--- Content provided by FirstRanker.com ---

11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

--- Content provided by FirstRanker.com ---

1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus

--- Content provided by FirstRanker.com ---

3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction

--- Content provided by FirstRanker.com ---

7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-

--- Content provided by FirstRanker.com ---

efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.

--- Content provided by FirstRanker.com ---

15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

--- Content provided by FirstRanker.com ---

COURSE OBJECTIVES
COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

--- Content provided by FirstRanker.com ---

Sl.No.
Name of the experiment
Page No.

--- Content provided by FirstRanker.com ---

CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus

--- Content provided by FirstRanker.com ---

11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15

--- Content provided by FirstRanker.com ---

4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6

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Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43

--- Content provided by FirstRanker.com ---

10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63

--- Content provided by FirstRanker.com ---

14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75

--- Content provided by FirstRanker.com ---

PROJECT WORK 81

8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

--- Content provided by FirstRanker.com ---

THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:

--- Content provided by FirstRanker.com ---

To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

--- Content provided by FirstRanker.com ---

(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in

--- Content provided by FirstRanker.com ---

which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.

--- Content provided by FirstRanker.com ---

Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

--- Content provided by FirstRanker.com ---

Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d

--- Content provided by FirstRanker.com ---

2
(10 + x)

cm
2

--- Content provided by FirstRanker.com ---

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

--- Content provided by FirstRanker.com ---

9 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.

--- Content provided by FirstRanker.com ---

4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

--- Content provided by FirstRanker.com ---

Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm

--- Content provided by FirstRanker.com ---

5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0

--- Content provided by FirstRanker.com ---

C ? 100
0
C
9. Maximum temperature of the hot plate = 170
0

--- Content provided by FirstRanker.com ---

C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V

--- Content provided by FirstRanker.com ---

14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200

--- Content provided by FirstRanker.com ---

0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:
Sl. No. Voltmeter

--- Content provided by FirstRanker.com ---

V
Ammeter
A
Main heater (
0

--- Content provided by FirstRanker.com ---

C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

--- Content provided by FirstRanker.com ---

Schematic view of the test set-up:

--- Content provided by FirstRanker.com ---

Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.

--- Content provided by FirstRanker.com ---

3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

--- Content provided by FirstRanker.com ---

FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

--- Content provided by FirstRanker.com ---

DEPARTMENT OF
MECHANICAL ENGINEERING

--- Content provided by FirstRanker.com ---

ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

Name : _______________________________________
Register No. : _______________________________________

--- Content provided by FirstRanker.com ---

Section : _______________________________________

--- Content provided by FirstRanker.com ---

LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

is committed to provide highly disciplined, conscientious and

--- Content provided by FirstRanker.com ---

enterprising professionals conforming to global standards through value based quality education and training.



? To provide competent technical manpower capable of meeting requirements of the industry

--- Content provided by FirstRanker.com ---

? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

--- Content provided by FirstRanker.com ---

DEPARTMENT OF MECHANICAL ENGINEERING



Rendering the services to the global needs of engineering industries by educating students to become

--- Content provided by FirstRanker.com ---

professionally sound mechanical engineers of excellent caliber



To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on

--- Content provided by FirstRanker.com ---

experience and to inculcate the spirit of moral values and ethics to serve the society

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

VISION
MISSION
VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould

--- Content provided by FirstRanker.com ---

them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth

--- Content provided by FirstRanker.com ---

To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up

--- Content provided by FirstRanker.com ---

their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME OUTCOMES (POs)

--- Content provided by FirstRanker.com ---

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications

--- Content provided by FirstRanker.com ---

4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability

--- Content provided by FirstRanker.com ---

8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills

--- Content provided by FirstRanker.com ---

11. To develop and manage projects in multidisciplinary environments

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

ME6512 ? THERMAL ENGINEERING LABORATORY ? II



? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the

--- Content provided by FirstRanker.com ---

performance of refrigeration cycle / components

LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus

--- Content provided by FirstRanker.com ---

2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder

--- Content provided by FirstRanker.com ---

7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

--- Content provided by FirstRanker.com ---

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System

--- Content provided by FirstRanker.com ---

15. Performance test in a fluidized Bed Cooling Tower



1. Able to find out the thermal conductivity of various materials.

--- Content provided by FirstRanker.com ---

2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials

--- Content provided by FirstRanker.com ---

6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.

--- Content provided by FirstRanker.com ---

11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures

--- Content provided by FirstRanker.com ---

14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

--- Content provided by FirstRanker.com ---

COURSE OBJECTIVES
COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

CONTENTS


Sl.No.
Name of the experiment

--- Content provided by FirstRanker.com ---

Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe

--- Content provided by FirstRanker.com ---

apparatus
11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder

--- Content provided by FirstRanker.com ---

15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS

--- Content provided by FirstRanker.com ---

6
Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39

--- Content provided by FirstRanker.com ---

9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58

--- Content provided by FirstRanker.com ---

13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS

--- Content provided by FirstRanker.com ---

16 Air conditioning test rig 75
PROJECT WORK 81

8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

--- Content provided by FirstRanker.com ---

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup

--- Content provided by FirstRanker.com ---

(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to

--- Content provided by FirstRanker.com ---

prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater

--- Content provided by FirstRanker.com ---

assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved

--- Content provided by FirstRanker.com ---

aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK

--- Content provided by FirstRanker.com ---

3. Area, A = ( ?/4) d
2
(10 + x)

cm

--- Content provided by FirstRanker.com ---

2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.

--- Content provided by FirstRanker.com ---

2. Increase the voltage gradually.

9 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there

--- Content provided by FirstRanker.com ---

is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

--- Content provided by FirstRanker.com ---

Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm

--- Content provided by FirstRanker.com ---

4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40

--- Content provided by FirstRanker.com ---

0
C ? 100
0
C
9. Maximum temperature of the hot plate = 170

--- Content provided by FirstRanker.com ---

0
C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)

--- Content provided by FirstRanker.com ---

13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)

--- Content provided by FirstRanker.com ---

18. Temperature indicator = 0 ? 200
0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm

--- Content provided by FirstRanker.com ---

21. Specimen used = Press wood

--- Content provided by FirstRanker.com ---

10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:

--- Content provided by FirstRanker.com ---

Sl. No. Voltmeter
V
Ammeter
A
Main heater (

--- Content provided by FirstRanker.com ---

0
C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

--- Content provided by FirstRanker.com ---

Schematic view of the test set-up:

--- Content provided by FirstRanker.com ---

Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water

--- Content provided by FirstRanker.com ---

is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from

--- Content provided by FirstRanker.com ---

thermocouple readings and is adjusted accordingly.

11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably

--- Content provided by FirstRanker.com ---

steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:

--- Content provided by FirstRanker.com ---

Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded

--- Content provided by FirstRanker.com ---

hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

?

--- Content provided by FirstRanker.com ---

DEPARTMENT OF
MECHANICAL ENGINEERING

--- Content provided by FirstRanker.com ---

ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

--- Content provided by FirstRanker.com ---

LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

--- Content provided by FirstRanker.com ---

? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart

--- Content provided by FirstRanker.com ---

and soul


DEPARTMENT OF MECHANICAL ENGINEERING

--- Content provided by FirstRanker.com ---

Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

--- Content provided by FirstRanker.com ---

To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

VISION
MISSION

--- Content provided by FirstRanker.com ---

VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

--- Content provided by FirstRanker.com ---

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence

--- Content provided by FirstRanker.com ---

To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design

--- Content provided by FirstRanker.com ---

products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies

--- Content provided by FirstRanker.com ---

5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering

--- Content provided by FirstRanker.com ---

2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools

--- Content provided by FirstRanker.com ---

6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms

--- Content provided by FirstRanker.com ---

9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

--- Content provided by FirstRanker.com ---

? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

--- Content provided by FirstRanker.com ---

LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder

--- Content provided by FirstRanker.com ---

4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant

--- Content provided by FirstRanker.com ---

9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system

--- Content provided by FirstRanker.com ---

12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

--- Content provided by FirstRanker.com ---

1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection

--- Content provided by FirstRanker.com ---

experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

--- Content provided by FirstRanker.com ---

8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.

--- Content provided by FirstRanker.com ---

12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC

--- Content provided by FirstRanker.com ---

Boiler.



COURSE OBJECTIVES

--- Content provided by FirstRanker.com ---

COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

--- Content provided by FirstRanker.com ---

Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS

--- Content provided by FirstRanker.com ---

1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11

--- Content provided by FirstRanker.com ---

3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21

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5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31

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7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47

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CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14

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Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate

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method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters

--- Content provided by FirstRanker.com ---

together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples

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No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

--- Content provided by FirstRanker.com ---

Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2

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(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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9 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help

--- Content provided by FirstRanker.com ---

of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:

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1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm

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6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100

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0
C
9. Maximum temperature of the hot plate = 170
0
C

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10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V

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15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0

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C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:
Sl. No. Voltmeter
V

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Ammeter
A
Main heater (
0
C) Test Plate (

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0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:

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1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single

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phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.

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8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

--- Content provided by FirstRanker.com ---

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

--- Content provided by FirstRanker.com ---

Applications:
Pipe lines, IC engines, heat exchangers

--- Content provided by FirstRanker.com ---

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.

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3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?

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8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?

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13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?

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18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce
FirstRanker.com - FirstRanker's Choice

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1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

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DEPARTMENT OF
MECHANICAL ENGINEERING

--- Content provided by FirstRanker.com ---

ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL

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2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

--- Content provided by FirstRanker.com ---

? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels

--- Content provided by FirstRanker.com ---

? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul


DEPARTMENT OF MECHANICAL ENGINEERING

--- Content provided by FirstRanker.com ---

Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

--- Content provided by FirstRanker.com ---

To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

VISION

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MISSION
VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals

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2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which

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enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt

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and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able

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1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution

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5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both

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verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus

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3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)

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8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:

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11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus

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3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction

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7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-

--- Content provided by FirstRanker.com ---

efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.

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15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.

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CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus

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11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15

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4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6

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Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43

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10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63

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14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75

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PROJECT WORK 81

8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:

--- Content provided by FirstRanker.com ---

To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in

--- Content provided by FirstRanker.com ---

which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.

--- Content provided by FirstRanker.com ---

Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

--- Content provided by FirstRanker.com ---

Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d

--- Content provided by FirstRanker.com ---

2
(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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9 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.

--- Content provided by FirstRanker.com ---

4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

--- Content provided by FirstRanker.com ---

Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm

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5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0

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C ? 100
0
C
9. Maximum temperature of the hot plate = 170
0

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C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V

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14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200

--- Content provided by FirstRanker.com ---

0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:
Sl. No. Voltmeter

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V
Ammeter
A
Main heater (
0

--- Content provided by FirstRanker.com ---

C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:

--- Content provided by FirstRanker.com ---

Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.

--- Content provided by FirstRanker.com ---

3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.

--- Content provided by FirstRanker.com ---

7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be

--- Content provided by FirstRanker.com ---

k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat

--- Content provided by FirstRanker.com ---

exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

1. Define ? Thermal Conductivity

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2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?

--- Content provided by FirstRanker.com ---

7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.

--- Content provided by FirstRanker.com ---

12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.

--- Content provided by FirstRanker.com ---

17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

--- Content provided by FirstRanker.com ---

Viva ? voce

--- Content provided by FirstRanker.com ---

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

--- Content provided by FirstRanker.com ---

THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

--- Content provided by FirstRanker.com ---

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus

--- Content provided by FirstRanker.com ---

(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is

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transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside

--- Content provided by FirstRanker.com ---

an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm

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3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm
FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

?

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DEPARTMENT OF
MECHANICAL ENGINEERING

--- Content provided by FirstRanker.com ---

ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

--- Content provided by FirstRanker.com ---

LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

--- Content provided by FirstRanker.com ---

? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart

--- Content provided by FirstRanker.com ---

and soul


DEPARTMENT OF MECHANICAL ENGINEERING

--- Content provided by FirstRanker.com ---

Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

--- Content provided by FirstRanker.com ---

To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

VISION
MISSION

--- Content provided by FirstRanker.com ---

VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

--- Content provided by FirstRanker.com ---

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence

--- Content provided by FirstRanker.com ---

To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design

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products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies

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5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

--- Content provided by FirstRanker.com ---

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering

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2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools

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6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms

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9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder

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4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant

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9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system

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12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection

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experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.

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12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC

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Boiler.



COURSE OBJECTIVES

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COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS

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1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11

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3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21

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5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31

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7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47

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CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14

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Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate

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method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters

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together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples

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No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2

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(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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9 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help

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of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:

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1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm

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6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100

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0
C
9. Maximum temperature of the hot plate = 170
0
C

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10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V

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15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0

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C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:
Sl. No. Voltmeter
V

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Ammeter
A
Main heater (
0
C) Test Plate (

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0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:

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1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single

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phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.

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8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.

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3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?

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8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?

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13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?

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18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:

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To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple

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(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.

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There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.

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4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.

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4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging

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k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:

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Sl.
No.
Voltage
(V)
Current

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(A)
Heater Temperature
(
0
C)

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Asbestos Temperature
(
0
C)
Saw dust

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Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?



DEPARTMENT OF

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MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

--- Content provided by FirstRanker.com ---

Name : _______________________________________

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Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

--- Content provided by FirstRanker.com ---

? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

--- Content provided by FirstRanker.com ---

Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

VISION
MISSION
VISION
MISSION

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4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals

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To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them

--- Content provided by FirstRanker.com ---

3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills

--- Content provided by FirstRanker.com ---

To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering

--- Content provided by FirstRanker.com ---

and to create awareness about the need for lifelong learning and pursuing advanced degrees

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME OUTCOMES (POs)

--- Content provided by FirstRanker.com ---

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship

--- Content provided by FirstRanker.com ---

3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical

--- Content provided by FirstRanker.com ---

environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination

--- Content provided by FirstRanker.com ---

10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

--- Content provided by FirstRanker.com ---

? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:

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1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall

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6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

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REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor

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14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus

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5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.

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10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at

--- Content provided by FirstRanker.com ---

various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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CONTENTS


Sl.No.

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Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2

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Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3
Determination of heat transfer coefficient under natural convection from a

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vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27

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CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34

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8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51

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12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72

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ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

--- Content provided by FirstRanker.com ---

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:

--- Content provided by FirstRanker.com ---

(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:

--- Content provided by FirstRanker.com ---

The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.

--- Content provided by FirstRanker.com ---

Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts

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on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:
1. Power input, Q = V ? A / 2 W

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2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:

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1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

9 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do

--- Content provided by FirstRanker.com ---

not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm

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3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm

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8. Mean temperature range = 40
0
C ? 100
0
C

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9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)

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12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)

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17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C
19. Width of gap between two heater plates (x) = 2.5 mm

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20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulation:
Sl. No. Voltmeter
V
Ammeter
A

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Main heater (
0
C) Test Plate (
0
C)

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T1 T2 T3 T4 T5 T6



Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.

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2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.

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5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

Outcome:

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From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

Applications:

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Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins

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5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?

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10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?

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15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?

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20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE

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APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:

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(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter

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Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:

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1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the

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experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:

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The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.

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L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.
No.

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Voltage
(V)
Current
(A)
Heater Temperature

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(
0
C)
Asbestos Temperature
(

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0
C)
Saw dust
Temperature (
0

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C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.

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3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by

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thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m

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2
-K

Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe

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apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:
Exhaust pipe lines, IC engines, heat exchangers

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FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart

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and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION

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VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence

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To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design

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products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies

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5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering

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2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools

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6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms

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9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder

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4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant

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9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system

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12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection

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experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.

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12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC

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Boiler.



COURSE OBJECTIVES

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COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS

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1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11

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3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21

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5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31

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7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47

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CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14

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Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate

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method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters

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together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples

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No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2

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(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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9 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help

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of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:

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1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm

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6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100

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0
C
9. Maximum temperature of the hot plate = 170
0
C

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10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V

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15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0

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C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:
Sl. No. Voltmeter
V

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Ammeter
A
Main heater (
0
C) Test Plate (

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0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:

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1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single

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phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.

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8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.

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3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?

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8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?

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13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?

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18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:

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To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple

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(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.

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There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.

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4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.

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4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging

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k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:

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Sl.
No.
Voltage
(V)
Current

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(A)
Heater Temperature
(
0
C)

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Asbestos Temperature
(
0
C)
Saw dust

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Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos

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layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:

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The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)

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6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?

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11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.

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16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce
FirstRanker.com - FirstRanker's Choice

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1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL

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2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

--- Content provided by FirstRanker.com ---

? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels

--- Content provided by FirstRanker.com ---

? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

--- Content provided by FirstRanker.com ---

To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

VISION

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MISSION
VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals

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2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which

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enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt

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and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able

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1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution

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5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both

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verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus

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3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)

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8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:

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11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus

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3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction

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7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-

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efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.

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15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.

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CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus

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11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15

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4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6

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Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43

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10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63

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14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75

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PROJECT WORK 81

8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:

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To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in

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which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.

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Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d

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2
(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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9 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.

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4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

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Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm

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5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0

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C ? 100
0
C
9. Maximum temperature of the hot plate = 170
0

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C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V

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14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200

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0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:
Sl. No. Voltmeter

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V
Ammeter
A
Main heater (
0

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C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.

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3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.

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7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be

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k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat

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exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity

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2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?

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7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.

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12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.

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17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

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Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus

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(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is

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transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside

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an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm

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3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.

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3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)

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Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found

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Tabulation:
Sl.
No.
Voltage
(V)

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Current
(A)
Heater Temperature
(
0

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C)
Asbestos Temperature
(
0
C)

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Saw dust
Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.

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5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.

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Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

--- Content provided by FirstRanker.com ---

Applications:
Exhaust pipe lines, IC engines, heat exchangers

--- Content provided by FirstRanker.com ---

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?

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5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?

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10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow

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15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.

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20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:

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To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of

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the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

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When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

--- Content provided by FirstRanker.com ---

DEPARTMENT OF
MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

--- Content provided by FirstRanker.com ---

V SEMESTER - R 2013

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

--- Content provided by FirstRanker.com ---

LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

--- Content provided by FirstRanker.com ---

? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

--- Content provided by FirstRanker.com ---

DEPARTMENT OF MECHANICAL ENGINEERING

--- Content provided by FirstRanker.com ---

Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

--- Content provided by FirstRanker.com ---

To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

VISION
MISSION
VISION

--- Content provided by FirstRanker.com ---

MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

--- Content provided by FirstRanker.com ---

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex

--- Content provided by FirstRanker.com ---

software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills

--- Content provided by FirstRanker.com ---

4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning

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To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the

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career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society

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7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with

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coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:

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HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube

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5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface

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10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes

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13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.

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4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system

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13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES

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7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6

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2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3

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Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5

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Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7

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Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS

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11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68

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15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT

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USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate

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assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The

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heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:

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1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2

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Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently

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5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm

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2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm

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7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100
0

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C
9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm

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11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A

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16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C

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19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter
V
Ammeter

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A
Main heater (
0
C) Test Plate (
0

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C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.

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Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.

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4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.

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4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?

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9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?

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14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?

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19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF

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PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus

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Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter

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(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm

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5. The effective length of the above = 500 mm

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Precautions:

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1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W

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Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material

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k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.

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No.
Voltage
(V)
Current
(A)

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Heater Temperature
(
0
C)
Asbestos Temperature

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(
0
C)
Saw dust
Temperature (

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0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.

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2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.

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6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.

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The thermal conductivity of resistive material = _________________ W /m
2
-K

Outcome:

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From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:

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Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. Define ? Nusselt Number(Nu)

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2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)

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7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?

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12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?

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17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION

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FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The

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temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold

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fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Schematic view of the test set-up:
mm

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mm
FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?



DEPARTMENT OF

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MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

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Name : _______________________________________

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Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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--- Content provided by FirstRanker.com ---

VISION
MISSION
VISION
MISSION

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4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals

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To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them

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3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills

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To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering

--- Content provided by FirstRanker.com ---

and to create awareness about the need for lifelong learning and pursuing advanced degrees

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME OUTCOMES (POs)

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On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship

--- Content provided by FirstRanker.com ---

3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical

--- Content provided by FirstRanker.com ---

environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination

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10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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ME6512 ? THERMAL ENGINEERING LABORATORY ? II

--- Content provided by FirstRanker.com ---

? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:

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1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall

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6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

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REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor

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14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus

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5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.

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10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at

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various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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CONTENTS


Sl.No.

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Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2

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Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3
Determination of heat transfer coefficient under natural convection from a

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vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27

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CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34

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8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51

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12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72

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ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

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Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:

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(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:

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The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.

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Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts

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on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:
1. Power input, Q = V ? A / 2 W

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2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:

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1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do

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not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm

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3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm

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8. Mean temperature range = 40
0
C ? 100
0
C

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9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)

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12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)

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17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C
19. Width of gap between two heater plates (x) = 2.5 mm

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20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter
V
Ammeter
A

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Main heater (
0
C) Test Plate (
0
C)

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T1 T2 T3 T4 T5 T6



Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.

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2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.

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5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

Outcome:

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From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

Applications:

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Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins

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5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?

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10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?

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15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?

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20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE

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APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:

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(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter

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Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:

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1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the

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experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:

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The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.

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L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.
No.

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Voltage
(V)
Current
(A)
Heater Temperature

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(
0
C)
Asbestos Temperature
(

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0
C)
Saw dust
Temperature (
0

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C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.

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3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by

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thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m

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2
-K

Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe

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apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?

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3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection

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8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?

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13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?

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18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

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Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:

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(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:

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The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is

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measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the

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relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Schematic view of the test set-up:
mm
mm

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19 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Diameter of the tube(d) = 40 mm

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2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300

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0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V

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8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

Tabulation:
Sl. No.

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Voltage Current Temperature of Thermocouple (
0
c)

V A

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T1 T2 T3 T4 T5 T6

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FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION

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MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex

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software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills

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4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning

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To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the

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career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society

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7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with

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coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:

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HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube

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5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface

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10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes

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13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.

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4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system

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13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES

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7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6

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2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3

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Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5

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Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7

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Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS

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11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68

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15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT

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USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate

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assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The

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heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:

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1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2

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Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently

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5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm

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2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm

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7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100
0

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C
9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm

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11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A

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16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C

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19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulation:
Sl. No. Voltmeter
V
Ammeter

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A
Main heater (
0
C) Test Plate (
0

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C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.

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Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.

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4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.

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4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?

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9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?

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14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?

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19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF

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PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus

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Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter

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(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm

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5. The effective length of the above = 500 mm

14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:

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1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W

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Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material

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k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.

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No.
Voltage
(V)
Current
(A)

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Heater Temperature
(
0
C)
Asbestos Temperature

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(
0
C)
Saw dust
Temperature (

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0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.

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2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.

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6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.

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The thermal conductivity of resistive material = _________________ W /m
2
-K

Outcome:

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From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:

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Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. Define ? Nusselt Number(Nu)

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2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)

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7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?

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12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?

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17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION

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FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The

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temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold

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fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Schematic view of the test set-up:
mm

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mm

19 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.

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5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A

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7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

Tabulation:

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Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m

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2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (

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0
C) ?
2. hL / k = A { g L
3
?T Cp ?/2v

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2
}
n

Where, hL / k are called Nusselt Number.

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L
3
g?T / v
2
is called Grashof number.

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?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid

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? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta

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For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)

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0.25
for 10
4
< Gr.Pr.<10
8

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hL / k = 0.13 (Gr.Pr)
1/3
for 10
8

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< Gr.Pr.<10
12
Here, L = Length of the cylinder

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FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart

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and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION

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VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence

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To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design

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products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies

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5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering

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2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools

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6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms

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9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder

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4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant

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9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system

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12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection

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experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.

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12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC

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Boiler.



COURSE OBJECTIVES

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COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS

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1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11

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3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21

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5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31

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7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47

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CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14

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Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate

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method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters

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together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples

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No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2

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(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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9 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help

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of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:

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1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm

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6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100

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0
C
9. Maximum temperature of the hot plate = 170
0
C

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10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V

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15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0

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C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:
Sl. No. Voltmeter
V

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Ammeter
A
Main heater (
0
C) Test Plate (

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0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:

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1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single

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phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.

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8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.

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3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?

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8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?

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13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?

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18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:

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To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple

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(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.

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There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.

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4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.

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4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging

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k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:

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Sl.
No.
Voltage
(V)
Current

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(A)
Heater Temperature
(
0
C)

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Asbestos Temperature
(
0
C)
Saw dust

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Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos

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layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:

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The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)

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6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?

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11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.

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16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical

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tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which

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in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.

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The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Schematic view of the test set-up:

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mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch

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Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples

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6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}

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Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W

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Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L
3

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?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v
2

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is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid

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v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity

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?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.

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hL / k = 0.56 (Gr.Pr)
0.25
for 10
4
< Gr.Pr.<10

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8

hL / k = 0.13 (Gr.Pr)
1/3
for 10

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8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).

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3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:

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The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m

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2
K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing

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heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________

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Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and

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enterprising professionals conforming to global standards through value based quality education and training.



? To provide competent technical manpower capable of meeting requirements of the industry

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? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING



Rendering the services to the global needs of engineering industries by educating students to become

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professionally sound mechanical engineers of excellent caliber



To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on

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experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould

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them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth

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To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up

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their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME OUTCOMES (POs)

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On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications

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4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability

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8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills

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11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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ME6512 ? THERMAL ENGINEERING LABORATORY ? II



? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the

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performance of refrigeration cycle / components

LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus

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2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder

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7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

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REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System

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15. Performance test in a fluidized Bed Cooling Tower



1. Able to find out the thermal conductivity of various materials.

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2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials

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6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.

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11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures

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14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
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CONTENTS


Sl.No.
Name of the experiment

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Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe

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apparatus
11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder

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15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS

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6
Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39

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9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58

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13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS

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16 Air conditioning test rig 75
PROJECT WORK 81

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Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

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Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup

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(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to

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prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater

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assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved

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aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK

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3. Area, A = ( ?/4) d
2
(10 + x)

cm

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2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.

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2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there

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is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

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Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm

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4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40

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0
C ? 100
0
C
9. Maximum temperature of the hot plate = 170

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0
C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)

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13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)

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18. Temperature indicator = 0 ? 200
0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm

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21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:

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Sl. No. Voltmeter
V
Ammeter
A
Main heater (

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0
C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water

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is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from

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thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably

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steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:

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Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded

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hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.

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6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer

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11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?

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16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

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Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup

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(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter
Theory:

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The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in

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the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:
1. Diameter of the heater Rod = 20 mm.

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2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).

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2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by

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Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging

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material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.
No.
Voltage

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(V)
Current
(A)
Heater Temperature
(

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0
C)
Asbestos Temperature
(
0

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C)
Saw dust
Temperature (
0
C)

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T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.

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4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.

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7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2

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-K

Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC

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engines, heat exchangers, etc. where heat transfer is to be found.

Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?

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4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?

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9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?

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14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis

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19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

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Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:
(i) Experimental setup

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(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at

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the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

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When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Schematic view of the test set-up:
mm
mm

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19 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm

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3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0

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C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V

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9. Heater = Cartridge type (400 W)

Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (

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0
c)

V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:

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1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2
K

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As = Area of heat transfer surface = ? x d x l m
2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0

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C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0
C) ?

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2. hL / k = A { g L
3
?T Cp ?/2v
2
}

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n

Where, hL / k are called Nusselt Number.
L
3

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g?T / v
2
is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.

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Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid

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? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0

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K
-1

Where Tf = (Ts + Ta )/ 2

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For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25
for 10

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4
< Gr.Pr.<10
8

hL / k = 0.13 (Gr.Pr)

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1/3
for 10
8
< Gr.Pr.<10
12

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Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

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Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2

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K
Experimental = ______________ W/ m
2
K

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Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?

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3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?

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8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer

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13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.

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18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce
FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION

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MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex

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software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills

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4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning

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To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the

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career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society

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7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with

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coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:

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HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube

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5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface

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10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes

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13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.

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4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system

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13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES

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7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6

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2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3

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Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5

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Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7

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Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS

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11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68

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15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT

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USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate

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assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The

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heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:

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1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2

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Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently

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5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm

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2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm

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7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100
0

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C
9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm

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11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A

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16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C

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19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulation:
Sl. No. Voltmeter
V
Ammeter

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A
Main heater (
0
C) Test Plate (
0

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C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.

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Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.

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4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.

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4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?

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9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?

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14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?

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19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF

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PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus

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Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter

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(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm

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5. The effective length of the above = 500 mm

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Precautions:

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1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W

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Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material

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k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.

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No.
Voltage
(V)
Current
(A)

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Heater Temperature
(
0
C)
Asbestos Temperature

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(
0
C)
Saw dust
Temperature (

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0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.

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2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.

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6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.

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The thermal conductivity of resistive material = _________________ W /m
2
-K

Outcome:

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From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:

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Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. Define ? Nusselt Number(Nu)

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2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)

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7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?

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12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?

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17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION

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FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The

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temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold

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fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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Schematic view of the test set-up:
mm

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mm

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Specifications:

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1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.

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5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A

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7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

Tabulation:

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Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m

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2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (

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0
C) ?
2. hL / k = A { g L
3
?T Cp ?/2v

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2
}
n

Where, hL / k are called Nusselt Number.

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L
3
g?T / v
2
is called Grashof number.

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?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid

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? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta

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For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)

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0.25
for 10
4
< Gr.Pr.<10
8

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hL / k = 0.13 (Gr.Pr)
1/3
for 10
8

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< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.

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4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as

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Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m
2

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K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC

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engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?

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6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?

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11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.

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16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to

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the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?



DEPARTMENT OF

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MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

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Name : _______________________________________

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Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION
MISSION

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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals

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To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them

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3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills

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To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering

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and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME OUTCOMES (POs)

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On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship

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3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical

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environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination

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10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:

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1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall

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6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

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REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor

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14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus

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5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.

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10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at

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various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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CONTENTS


Sl.No.

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Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2

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Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3
Determination of heat transfer coefficient under natural convection from a

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vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27

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CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34

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8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51

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12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72

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ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

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Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:

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(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:

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The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.

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Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts

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on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:
1. Power input, Q = V ? A / 2 W

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2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:

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1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do

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not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm

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3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm

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8. Mean temperature range = 40
0
C ? 100
0
C

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9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)

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12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)

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17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C
19. Width of gap between two heater plates (x) = 2.5 mm

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20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulation:
Sl. No. Voltmeter
V
Ammeter
A

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Main heater (
0
C) Test Plate (
0
C)

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T1 T2 T3 T4 T5 T6



Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.

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2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.

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5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

Outcome:

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From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

Applications:

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Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins

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5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?

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10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?

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15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?

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20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE

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APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:

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(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter

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Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:

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1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the

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experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:

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The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.

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L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.
No.

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Voltage
(V)
Current
(A)
Heater Temperature

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(
0
C)
Asbestos Temperature
(

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0
C)
Saw dust
Temperature (
0

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C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.

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3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by

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thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m

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2
-K

Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe

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apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?

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3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection

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8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?

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13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?

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18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

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Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:

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(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:

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The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is

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measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the

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relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Schematic view of the test set-up:
mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm

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2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300

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0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V

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8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

Tabulation:
Sl. No.

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Voltage Current Temperature of Thermocouple (
0
c)

V A

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T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2

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K
As = Area of heat transfer surface = ? x d x l m
2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7

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0
C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0

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C) ?
2. hL / k = A { g L
3
?T Cp ?/2v
2

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}
n

Where, hL / k are called Nusselt Number.
L

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3
g?T / v
2
is called Grashof number.
?Cp / k called Prandtl Number.

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A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid

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Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)

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0
K
-1

Where Tf = (Ts + Ta )/ 2

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For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25

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for 10
4
< Gr.Pr.<10
8

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hL / k = 0.13 (Gr.Pr)
1/3
for 10
8
< Gr.Pr.<10

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12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).

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5. Repeat the experiment at different heat inputs.

Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m

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2
K
Experimental = ______________ W/ m
2
K

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Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be

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found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)

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2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness

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7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?

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12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.

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17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No. 4

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION

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FROM A TUBE

Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater

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is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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Tabulations:

Sl. No. Voltage Current Temperature in (
0
C)

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Manometer
reading of water
in h in meter

(V) (A)

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T1

T2

T3

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T4

T5

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T6

h1
cm
h2

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cm

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FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________

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Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and

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enterprising professionals conforming to global standards through value based quality education and training.



? To provide competent technical manpower capable of meeting requirements of the industry

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? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING



Rendering the services to the global needs of engineering industries by educating students to become

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professionally sound mechanical engineers of excellent caliber



To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on

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experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould

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them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth

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To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up

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their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME OUTCOMES (POs)

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On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications

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4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability

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8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills

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11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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ME6512 ? THERMAL ENGINEERING LABORATORY ? II



? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the

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performance of refrigeration cycle / components

LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus

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2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder

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7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

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REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System

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15. Performance test in a fluidized Bed Cooling Tower



1. Able to find out the thermal conductivity of various materials.

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2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials

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6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.

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11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures

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14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
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CONTENTS


Sl.No.
Name of the experiment

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Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe

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apparatus
11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder

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15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS

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6
Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39

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9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58

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13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS

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16 Air conditioning test rig 75
PROJECT WORK 81

8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

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Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup

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(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to

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prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater

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assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved

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aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK

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3. Area, A = ( ?/4) d
2
(10 + x)

cm

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2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.

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2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there

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is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

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Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm

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4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40

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0
C ? 100
0
C
9. Maximum temperature of the hot plate = 170

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0
C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)

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13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)

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18. Temperature indicator = 0 ? 200
0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm

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21. Specimen used = Press wood

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Tabulation:

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Sl. No. Voltmeter
V
Ammeter
A
Main heater (

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0
C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water

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is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from

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thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably

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steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:

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Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded

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hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.

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6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer

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11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?

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16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

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Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup

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(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter
Theory:

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The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in

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the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:
1. Diameter of the heater Rod = 20 mm.

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2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).

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2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by

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Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging

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material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.
No.
Voltage

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(V)
Current
(A)
Heater Temperature
(

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0
C)
Asbestos Temperature
(
0

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C)
Saw dust
Temperature (
0
C)

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T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.

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4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.

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7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2

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-K

Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC

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engines, heat exchangers, etc. where heat transfer is to be found.

Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?

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4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?

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9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?

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14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis

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19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

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Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:
(i) Experimental setup

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(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at

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the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

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When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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Schematic view of the test set-up:
mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm

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3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0

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C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V

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9. Heater = Cartridge type (400 W)

Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (

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0
c)

V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:

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1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2
K

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As = Area of heat transfer surface = ? x d x l m
2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0

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C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0
C) ?

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2. hL / k = A { g L
3
?T Cp ?/2v
2
}

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n

Where, hL / k are called Nusselt Number.
L
3

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g?T / v
2
is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.

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Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid

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? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0

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K
-1

Where Tf = (Ts + Ta )/ 2

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For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25
for 10

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4
< Gr.Pr.<10
8

hL / k = 0.13 (Gr.Pr)

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1/3
for 10
8
< Gr.Pr.<10
12

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Here, L = Length of the cylinder

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Procedure:

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1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

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Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2

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K
Experimental = ______________ W/ m
2
K

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Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?

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3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?

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8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer

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13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.

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18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No. 4

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

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Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:

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(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

Theory:

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Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat

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supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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Tabulations:

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Sl. No. Voltage Current Temperature in (
0
C)
Manometer

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reading of water
in h in meter

(V) (A)
T1

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T2

T3

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T4

T5

T6

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h1
cm
h2
cm

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm

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3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300

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0
C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A

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10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.

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4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:

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1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady

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state is reached.
4. Note down the heater input.
FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION

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MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex

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software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills

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4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning

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To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the

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career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society

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7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with

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coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:

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HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube

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5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface

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10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes

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13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.

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4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system

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13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES

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CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6

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2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3

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Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5

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Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7

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Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS

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11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68

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15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT

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USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate

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assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The

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heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:

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1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2

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Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently

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5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm

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2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm

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7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100
0

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C
9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm

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11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A

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16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C

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19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter
V
Ammeter

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A
Main heater (
0
C) Test Plate (
0

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C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.

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Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.

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4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.

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4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?

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9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?

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14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?

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19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF

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PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus

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Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter

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(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm

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5. The effective length of the above = 500 mm

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Precautions:

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1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W

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Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material

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k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.

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No.
Voltage
(V)
Current
(A)

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Heater Temperature
(
0
C)
Asbestos Temperature

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(
0
C)
Saw dust
Temperature (

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0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.

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2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.

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6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.

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The thermal conductivity of resistive material = _________________ W /m
2
-K

Outcome:

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From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:

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Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. Define ? Nusselt Number(Nu)

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2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)

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7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?

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12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?

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17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION

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FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The

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temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold

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fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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Schematic view of the test set-up:
mm

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mm

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Specifications:

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1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.

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5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A

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7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

Tabulation:

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Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m

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2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (

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0
C) ?
2. hL / k = A { g L
3
?T Cp ?/2v

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2
}
n

Where, hL / k are called Nusselt Number.

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L
3
g?T / v
2
is called Grashof number.

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?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid

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? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta

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For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)

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0.25
for 10
4
< Gr.Pr.<10
8

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hL / k = 0.13 (Gr.Pr)
1/3
for 10
8

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< Gr.Pr.<10
12
Here, L = Length of the cylinder

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.

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4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as

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Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m
2

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K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC

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engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?

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6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?

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11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.

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16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to

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the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

Sl. No. Voltage Current Temperature in (
0

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C)
Manometer
reading of water
in h in meter

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(V) (A)
T1

T2

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T3

T4

T5

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T6

h1
cm

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h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer

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6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0
C
(Calibrated for chromel alumel thermocouple)

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8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.

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7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat

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input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)

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Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o
C)

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= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di

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2
?2gH x (?w / ?a) m
3
/hr
3. ha = qa /A(Ts- Ta) W / m

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2
K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

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Ta = Average temperature of air = (T1 + T6)/2
o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4

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o
C
Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m

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3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

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d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

using this procedure obtain the value of ?ha? for different air flow rate

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4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2
)/4]

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v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o
C
5. Nusselt Number:

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Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:
FirstRanker.com - FirstRanker's Choice

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1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL

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2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels

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? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION

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MISSION
VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals

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2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which

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enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt

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and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able

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1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution

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5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both

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verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus

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3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)

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8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:

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11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus

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3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction

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7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-

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efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.

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15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.

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CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus

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11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15

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4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6

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Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43

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10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63

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14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75

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PROJECT WORK 81

8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:

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To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in

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which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.

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Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d

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2
(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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9 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.

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4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

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Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm

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5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0

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C ? 100
0
C
9. Maximum temperature of the hot plate = 170
0

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C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V

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14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200

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0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:
Sl. No. Voltmeter

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V
Ammeter
A
Main heater (
0

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C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.

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3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.

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7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be

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k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat

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exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity

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2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?

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7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.

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12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.

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17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

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Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus

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(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is

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transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside

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an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm

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3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.

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3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)

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Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found

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Tabulation:
Sl.
No.
Voltage
(V)

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Current
(A)
Heater Temperature
(
0

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C)
Asbestos Temperature
(
0
C)

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Saw dust
Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.

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5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.

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Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?

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5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?

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10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow

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15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.

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20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:

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To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of

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the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

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When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Schematic view of the test set-up:
mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm

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4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel

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thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0

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c)

V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Heat transfer coefficient is given by

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h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m

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2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C

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q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L

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3
?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v

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2
is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface

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K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid

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G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K

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-1

Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been

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determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25
for 10
4

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< Gr.Pr.<10
8

hL / k = 0.13 (Gr.Pr)
1/3

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for 10
8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.

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2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

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Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K

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Experimental = ______________ W/ m
2
K

Outcomes:

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From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.

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4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.

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9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?

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14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness

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19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

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Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer

Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band

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heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to

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measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.


24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

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Sl. No. Voltage Current Temperature in (
0
C)
Manometer
reading of water

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in h in meter

(V) (A)
T1

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T2

T3

T4

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T5

T6

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h1
cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm

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4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0

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C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.

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5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference

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in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.

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4. Note down the heater input.

26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:

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1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (

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o
C)
= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr

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Q = Volume flow rate
Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m
3

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/hr
3. ha = qa /A(Ts- Ta) W / m
2
K
qa = Rate of which air is getting heated.

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A = Test section area = ? x Di x L m
2

Ta = Average temperature of air = (T1 + T6)/2
o

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C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C
Cd = 0.64

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H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m

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3

d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

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using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di

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2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o

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C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings

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6. Prandtl Number:

27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k

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Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

k = Thermal conductivity of fluid W/m

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2
K
Nu = 0.023 (Re)
0.8
(Pr)

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0.4
Bulk mean temperature = (T1 + T6)/2

Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection

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apparatus.
hactual = -------------- W/m
2
K
htheoritical = -------------- W/m

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2
K

Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection

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apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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FirstRanker.com - FirstRanker's Choice

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1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL

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2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels

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? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION

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MISSION
VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals

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2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which

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enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt

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and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able

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1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution

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5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both

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verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus

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3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)

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8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:

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11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus

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3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction

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7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-

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efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.

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15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.

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CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus

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11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15

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4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6

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Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43

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10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63

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14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75

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PROJECT WORK 81

8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:

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To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in

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which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.

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Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d

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2
(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.

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4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

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Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm

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5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0

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C ? 100
0
C
9. Maximum temperature of the hot plate = 170
0

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C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V

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14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200

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0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:
Sl. No. Voltmeter

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V
Ammeter
A
Main heater (
0

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C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.

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3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.

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7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be

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k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat

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exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity

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2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?

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7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.

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12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.

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17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

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Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus

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(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is

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transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside

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an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm

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3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.

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3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)

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Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found

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Tabulation:
Sl.
No.
Voltage
(V)

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Current
(A)
Heater Temperature
(
0

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C)
Asbestos Temperature
(
0
C)

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Saw dust
Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.

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5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.

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Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?

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5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?

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10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow

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15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.

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20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:

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To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of

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the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

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When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Schematic view of the test set-up:
mm
mm

19 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm

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4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel

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thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0

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c)

V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Heat transfer coefficient is given by

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h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m

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2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C

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q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L

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3
?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v

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2
is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface

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K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid

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G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K

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-1

Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been

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determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25
for 10
4

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< Gr.Pr.<10
8

hL / k = 0.13 (Gr.Pr)
1/3

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for 10
8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.

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2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

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Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K

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Experimental = ______________ W/ m
2
K

Outcomes:

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From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.

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4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.

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9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?

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14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness

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19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

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Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer

Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band

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heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to

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measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.


24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

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Sl. No. Voltage Current Temperature in (
0
C)
Manometer
reading of water

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in h in meter

(V) (A)
T1

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T2

T3

T4

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T5

T6

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h1
cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm

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4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0

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C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.

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5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference

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in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.

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4. Note down the heater input.

26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:

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1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (

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o
C)
= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr

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Q = Volume flow rate
Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m
3

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/hr
3. ha = qa /A(Ts- Ta) W / m
2
K
qa = Rate of which air is getting heated.

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A = Test section area = ? x Di x L m
2

Ta = Average temperature of air = (T1 + T6)/2
o

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C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C
Cd = 0.64

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H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m

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3

d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

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using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di

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2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o

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C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings

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6. Prandtl Number:

27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k

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Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

k = Thermal conductivity of fluid W/m

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2
K
Nu = 0.023 (Re)
0.8
(Pr)

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0.4
Bulk mean temperature = (T1 + T6)/2

Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection

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apparatus.
hactual = -------------- W/m
2
K
htheoritical = -------------- W/m

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2
K

Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection

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apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is meant by boiling and condensation?

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2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?

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7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?

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12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce
FirstRanker.com - FirstRanker's Choice
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?

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DEPARTMENT OF
MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION

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MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex

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software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills

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4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning

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To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the

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career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society

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7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with

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coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:

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HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube

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5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface

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10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes

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13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.

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4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system

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13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES

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CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6

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2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3

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Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5

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Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7

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Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS

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11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68

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15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT

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USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate

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assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The

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heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:

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1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2

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Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently

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5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm

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2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm

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7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100
0

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C
9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm

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11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A

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16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C

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19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter
V
Ammeter

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A
Main heater (
0
C) Test Plate (
0

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C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.

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Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.

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4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.

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4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?

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9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?

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14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?

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19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF

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PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus

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Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter

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(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm

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5. The effective length of the above = 500 mm

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Precautions:

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1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W

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Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material

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k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.

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No.
Voltage
(V)
Current
(A)

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Heater Temperature
(
0
C)
Asbestos Temperature

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(
0
C)
Saw dust
Temperature (

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0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.

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2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.

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6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.

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The thermal conductivity of resistive material = _________________ W /m
2
-K

Outcome:

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From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:

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Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. Define ? Nusselt Number(Nu)

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2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)

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7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?

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12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?

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17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION

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FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The

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temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold

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fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Schematic view of the test set-up:
mm

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mm

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Specifications:

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1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.

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5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A

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7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

Tabulation:

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Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m

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2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (

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0
C) ?
2. hL / k = A { g L
3
?T Cp ?/2v

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2
}
n

Where, hL / k are called Nusselt Number.

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L
3
g?T / v
2
is called Grashof number.

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?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid

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? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta

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For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)

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0.25
for 10
4
< Gr.Pr.<10
8

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hL / k = 0.13 (Gr.Pr)
1/3
for 10
8

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< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.

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4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as

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Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m
2

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K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC

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engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?

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6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?

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11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.

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16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to

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the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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Tabulations:

Sl. No. Voltage Current Temperature in (
0

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C)
Manometer
reading of water
in h in meter

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(V) (A)
T1

T2

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T3

T4

T5

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T6

h1
cm

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h2
cm

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Specifications:

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1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer

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6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0
C
(Calibrated for chromel alumel thermocouple)

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8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.

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7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat

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input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)

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Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o
C)

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= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di

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2
?2gH x (?w / ?a) m
3
/hr
3. ha = qa /A(Ts- Ta) W / m

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2
K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

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Ta = Average temperature of air = (T1 + T6)/2
o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4

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o
C
Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m

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3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

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d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

using this procedure obtain the value of ?ha? for different air flow rate

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4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2
)/4]

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v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o
C
5. Nusselt Number:

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Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

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Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m

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2

k = Thermal conductivity of fluid W/m
2
K

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Nu = 0.023 (Re)
0.8
(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

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Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m

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2
K
htheoritical = -------------- W/m
2
K

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Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?

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4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?

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9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.

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14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

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29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

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Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the

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thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The

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temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is

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the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm

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3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat

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input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the
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1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL

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2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels

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? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION

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MISSION
VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals

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2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which

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enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt

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and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able

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1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution

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5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both

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verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus

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3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)

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8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:

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11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus

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3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction

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7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-

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efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.

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15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
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CONTENTS

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Sl.No.
Name of the experiment
Page No.

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CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus

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11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15

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4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6

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Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43

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10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63

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14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75

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PROJECT WORK 81

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Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:

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To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in

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which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.

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Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d

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2
(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.

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4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

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Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm

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5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0

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C ? 100
0
C
9. Maximum temperature of the hot plate = 170
0

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C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V

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14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200

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0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter

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V
Ammeter
A
Main heater (
0

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C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.

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3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.

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7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be

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k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat

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exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity

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2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?

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7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.

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12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.

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17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

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Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus

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(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is

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transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside

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an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm

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3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.

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3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)

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Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found

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Tabulation:
Sl.
No.
Voltage
(V)

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Current
(A)
Heater Temperature
(
0

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C)
Asbestos Temperature
(
0
C)

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Saw dust
Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.

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5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.

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Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?

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5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?

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10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow

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15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.

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20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:

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To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of

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the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

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When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Schematic view of the test set-up:
mm
mm

19 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm

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4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel

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thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0

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c)

V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Heat transfer coefficient is given by

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h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m

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2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C

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q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L

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3
?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v

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2
is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface

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K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid

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G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K

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-1

Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been

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determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25
for 10
4

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< Gr.Pr.<10
8

hL / k = 0.13 (Gr.Pr)
1/3

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for 10
8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.

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2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

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Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K

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Experimental = ______________ W/ m
2
K

Outcomes:

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From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.

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4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.

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9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?

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14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness

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19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

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Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer

Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band

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heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to

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measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.


24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

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Sl. No. Voltage Current Temperature in (
0
C)
Manometer
reading of water

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in h in meter

(V) (A)
T1

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T2

T3

T4

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T5

T6

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h1
cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm

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4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0

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C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.

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5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference

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in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.

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4. Note down the heater input.

26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:

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1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (

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o
C)
= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr

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Q = Volume flow rate
Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m
3

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/hr
3. ha = qa /A(Ts- Ta) W / m
2
K
qa = Rate of which air is getting heated.

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A = Test section area = ? x Di x L m
2

Ta = Average temperature of air = (T1 + T6)/2
o

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C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C
Cd = 0.64

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H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m

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3

d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

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using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di

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2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o

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C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings

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6. Prandtl Number:

27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k

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Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

k = Thermal conductivity of fluid W/m

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2
K
Nu = 0.023 (Re)
0.8
(Pr)

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0.4
Bulk mean temperature = (T1 + T6)/2

Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection

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apparatus.
hactual = -------------- W/m
2
K
htheoritical = -------------- W/m

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2
K

Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection

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apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is meant by boiling and condensation?

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2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?

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7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?

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12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:

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When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly

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temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The

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apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:

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1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:

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1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.

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5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)

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6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.

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Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities

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Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter
reading
(V)

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Ammeter
reading
(A)
T1
(

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0
C)
T2
(
0

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C)
T3
(
0
C)

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T4
(
0
C)
T5

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(
0
C)
T6
(

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0
C)
T7
(
0

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C)
T8
(
0
C)

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FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?



DEPARTMENT OF

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MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

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Name : _______________________________________

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Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION
MISSION

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4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals

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To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them

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3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills

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To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering

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and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME OUTCOMES (POs)

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On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship

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3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical

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environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination

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10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:

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1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall

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6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

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REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor

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14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus

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5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.

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10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at

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various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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CONTENTS


Sl.No.

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Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2

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Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3
Determination of heat transfer coefficient under natural convection from a

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vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27

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CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34

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8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51

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12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72

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ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

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Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:

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(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:

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The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.

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Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts

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on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:
1. Power input, Q = V ? A / 2 W

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2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:

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1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do

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not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm

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3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm

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8. Mean temperature range = 40
0
C ? 100
0
C

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9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)

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12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)

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17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C
19. Width of gap between two heater plates (x) = 2.5 mm

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20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter
V
Ammeter
A

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Main heater (
0
C) Test Plate (
0
C)

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T1 T2 T3 T4 T5 T6



Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.

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2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.

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5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

Outcome:

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From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

Applications:

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Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins

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5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?

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10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?

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15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?

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20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE

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APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:

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(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter

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Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:

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1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the

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experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:

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The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.

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L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.
No.

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Voltage
(V)
Current
(A)
Heater Temperature

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(
0
C)
Asbestos Temperature
(

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0
C)
Saw dust
Temperature (
0

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C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.

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3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by

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thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m

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2
-K

Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe

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apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?

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3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection

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8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?

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13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?

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18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

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Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:

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(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:

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The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is

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measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the

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relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Schematic view of the test set-up:
mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm

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2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300

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0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V

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8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

Tabulation:
Sl. No.

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Voltage Current Temperature of Thermocouple (
0
c)

V A

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T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2

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K
As = Area of heat transfer surface = ? x d x l m
2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7

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0
C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0

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C) ?
2. hL / k = A { g L
3
?T Cp ?/2v
2

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}
n

Where, hL / k are called Nusselt Number.
L

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3
g?T / v
2
is called Grashof number.
?Cp / k called Prandtl Number.

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A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid

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Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)

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0
K
-1

Where Tf = (Ts + Ta )/ 2

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For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25

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for 10
4
< Gr.Pr.<10
8

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hL / k = 0.13 (Gr.Pr)
1/3
for 10
8
< Gr.Pr.<10

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12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).

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5. Repeat the experiment at different heat inputs.

Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m

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2
K
Experimental = ______________ W/ m
2
K

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Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be

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found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)

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2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness

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7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?

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12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.

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17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No. 4

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION

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FROM A TUBE

Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater

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is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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Tabulations:

Sl. No. Voltage Current Temperature in (
0
C)

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Manometer
reading of water
in h in meter

(V) (A)

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T1

T2

T3

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T4

T5

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T6

h1
cm
h2

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cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Pipe diameter outside (Do) = 40 mm

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2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C

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7. Temperature Indicator = Range 0 to 300
0
C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V

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9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.

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3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W

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Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.

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3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)

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Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o
C)
= T6 ? T1.

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2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di
2

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?2gH x (?w / ?a) m
3
/hr
3. ha = qa /A(Ts- Ta) W / m
2

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K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

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Ta = Average temperature of air = (T1 + T6)/2
o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o

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C
Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

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?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

d = diameter of orifice meter = 0.014 m

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g = acceleration due to gravity = 9.81 m/s
2

using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:

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Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature

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(T1 + T6)/2
o
C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number

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K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

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k = Thermal conductivity of fluid W/m
2
K
Nu = 0.023 (Re)

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0.8
(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

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Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m
2

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K
htheoritical = -------------- W/m
2
K

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Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.

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5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.

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10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?

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15. Define ? Momentum Thickness

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Viva ? voce

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29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:

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To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different

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materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A

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channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in

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series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm

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4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.

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3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as

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Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3

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Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter

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reading
(V)
Ammeter
reading
(A)

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T1
(
0
C)
T2

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(
0
C)
T3
(

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0
C)
T4
(
0

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C)
T5
(
0
C)

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T6
(
0
C)
T7

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(
0
C)
T8
(

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0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:

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The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

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Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


FirstRanker.com - FirstRanker's Choice

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1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL

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2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels

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? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION

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MISSION
VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals

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2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which

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enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt

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and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able

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1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution

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5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both

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verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus

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3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)

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8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:

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11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus

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3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction

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7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-

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efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.

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15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
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CONTENTS

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Sl.No.
Name of the experiment
Page No.

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CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus

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11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15

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4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6

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Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43

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10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63

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14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75

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PROJECT WORK 81

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Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:

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To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in

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which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.

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Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d

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2
(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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9 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.

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4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

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Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm

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5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0

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C ? 100
0
C
9. Maximum temperature of the hot plate = 170
0

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C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V

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14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200

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0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:
Sl. No. Voltmeter

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V
Ammeter
A
Main heater (
0

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C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.

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3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.

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7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be

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k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat

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exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity

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2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?

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7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.

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12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.

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17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

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Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus

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(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is

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transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside

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an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm

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3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.

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3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)

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Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found

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Tabulation:
Sl.
No.
Voltage
(V)

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Current
(A)
Heater Temperature
(
0

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C)
Asbestos Temperature
(
0
C)

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Saw dust
Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.

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5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.

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Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?

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5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?

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10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow

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15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.

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20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:

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To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of

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the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

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When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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Schematic view of the test set-up:
mm
mm

19 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm

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4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel

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thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0

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c)

V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Heat transfer coefficient is given by

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h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m

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2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C

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q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L

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3
?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v

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2
is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface

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K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid

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G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K

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-1

Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been

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determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25
for 10
4

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< Gr.Pr.<10
8

hL / k = 0.13 (Gr.Pr)
1/3

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for 10
8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.

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2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

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Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K

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Experimental = ______________ W/ m
2
K

Outcomes:

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From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.

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4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.

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9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?

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14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness

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19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

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Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer

Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band

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heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to

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measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.


24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

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Sl. No. Voltage Current Temperature in (
0
C)
Manometer
reading of water

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in h in meter

(V) (A)
T1

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T2

T3

T4

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T5

T6

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h1
cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm

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4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0

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C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.

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5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference

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in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.

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4. Note down the heater input.

26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:

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1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (

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o
C)
= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr

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Q = Volume flow rate
Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m
3

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/hr
3. ha = qa /A(Ts- Ta) W / m
2
K
qa = Rate of which air is getting heated.

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A = Test section area = ? x Di x L m
2

Ta = Average temperature of air = (T1 + T6)/2
o

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C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C
Cd = 0.64

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H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m

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3

d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

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using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di

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2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o

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C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings

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6. Prandtl Number:

27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k

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Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

k = Thermal conductivity of fluid W/m

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2
K
Nu = 0.023 (Re)
0.8
(Pr)

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0.4
Bulk mean temperature = (T1 + T6)/2

Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection

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apparatus.
hactual = -------------- W/m
2
K
htheoritical = -------------- W/m

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2
K

Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection

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apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is meant by boiling and condensation?

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2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?

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7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?

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12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:

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When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly

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temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The

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apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:

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1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:

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1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.

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5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)

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6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.

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Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities

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Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter
reading
(V)

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Ammeter
reading
(A)
T1
(

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0
C)
T2
(
0

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C)
T3
(
0
C)

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T4
(
0
C)
T5

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(
0
C)
T6
(

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0
C)
T7
(
0

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C)
T8
(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W

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b. Wood section = ---------------W
c. Asbestos section = ------------W

Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt

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and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.

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4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.

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8. Explain the significance of Fourier number.
9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce
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?



DEPARTMENT OF

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MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

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Name : _______________________________________

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Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION
MISSION

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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals

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To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them

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3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills

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To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering

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and to create awareness about the need for lifelong learning and pursuing advanced degrees

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PROGRAMME OUTCOMES (POs)

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On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship

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3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical

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environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination

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10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:

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1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall

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6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

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REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor

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14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus

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5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.

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10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at

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various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
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CONTENTS


Sl.No.

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Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2

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Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3
Determination of heat transfer coefficient under natural convection from a

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vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27

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CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34

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8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51

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12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72

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ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

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Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:

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(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:

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The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.

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Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts

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on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:
1. Power input, Q = V ? A / 2 W

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2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:

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1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do

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not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm

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3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm

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8. Mean temperature range = 40
0
C ? 100
0
C

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9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)

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12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)

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17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C
19. Width of gap between two heater plates (x) = 2.5 mm

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20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter
V
Ammeter
A

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Main heater (
0
C) Test Plate (
0
C)

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T1 T2 T3 T4 T5 T6



Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.

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2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.

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5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

Outcome:

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From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

Applications:

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Pipe lines, IC engines, heat exchangers

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins

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5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?

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10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?

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15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?

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20. State the advantages of dimensional analysis.

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Viva ? voce

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE

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APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:

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(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter

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Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:

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1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the

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experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:

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The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.

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L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.
No.

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Voltage
(V)
Current
(A)
Heater Temperature

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(
0
C)
Asbestos Temperature
(

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0
C)
Saw dust
Temperature (
0

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C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.

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3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by

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thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m

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2
-K

Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe

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apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:
Exhaust pipe lines, IC engines, heat exchangers

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?

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3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection

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8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?

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13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?

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18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

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Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:

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(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:

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The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is

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measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the

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relative motion of hot and cold fluid particles.

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Schematic view of the test set-up:
mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm

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2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300

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0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V

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8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

Tabulation:
Sl. No.

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Voltage Current Temperature of Thermocouple (
0
c)

V A

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T1 T2 T3 T4 T5 T6

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Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2

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K
As = Area of heat transfer surface = ? x d x l m
2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7

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0
C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0

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C) ?
2. hL / k = A { g L
3
?T Cp ?/2v
2

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}
n

Where, hL / k are called Nusselt Number.
L

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3
g?T / v
2
is called Grashof number.
?Cp / k called Prandtl Number.

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A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid

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Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)

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0
K
-1

Where Tf = (Ts + Ta )/ 2

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For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25

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for 10
4
< Gr.Pr.<10
8

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hL / k = 0.13 (Gr.Pr)
1/3
for 10
8
< Gr.Pr.<10

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12
Here, L = Length of the cylinder

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).

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5. Repeat the experiment at different heat inputs.

Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m

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2
K
Experimental = ______________ W/ m
2
K

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Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be

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found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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1. Define ? Grash of Number(Gr)

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2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness

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7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?

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12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.

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17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No. 4

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION

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FROM A TUBE

Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater

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is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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Tabulations:

Sl. No. Voltage Current Temperature in (
0
C)

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Manometer
reading of water
in h in meter

(V) (A)

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T1

T2

T3

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T4

T5

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T6

h1
cm
h2

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cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Pipe diameter outside (Do) = 40 mm

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2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C

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7. Temperature Indicator = Range 0 to 300
0
C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V

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9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.

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3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W

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Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.

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3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)

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Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o
C)
= T6 ? T1.

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2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di
2

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?2gH x (?w / ?a) m
3
/hr
3. ha = qa /A(Ts- Ta) W / m
2

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K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

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Ta = Average temperature of air = (T1 + T6)/2
o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o

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C
Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

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?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

d = diameter of orifice meter = 0.014 m

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g = acceleration due to gravity = 9.81 m/s
2

using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:

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Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature

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(T1 + T6)/2
o
C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number

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K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

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k = Thermal conductivity of fluid W/m
2
K
Nu = 0.023 (Re)

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0.8
(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

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Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m
2

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K
htheoritical = -------------- W/m
2
K

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Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.

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5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.

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10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?

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15. Define ? Momentum Thickness

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Viva ? voce

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29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:

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To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different

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materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A

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channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in

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series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm

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4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.

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3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as

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Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3

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Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter

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reading
(V)
Ammeter
reading
(A)

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T1
(
0
C)
T2

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(
0
C)
T3
(

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0
C)
T4
(
0

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C)
T5
(
0
C)

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T6
(
0
C)
T7

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(
0
C)
T8
(

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0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:

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The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

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Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. Define ? Heat Transfer

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2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?

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6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?
10. Define ? Heat Exchanger

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11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

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Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

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The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input

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power and dimmer stat is provided to vary the input power.

Procedure:

1. Switch on the unit and adjust the input power to the required extent.

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2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter
reading( V)

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Ammeter
reading (A)
T1
(
0

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C)
T2
(
0
C)

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T3
(
0
C)
T4

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(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the

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inner sphere, and the outer sphere respectively.

FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION

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MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex

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software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills

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4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning

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To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the

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career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society

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7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with

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coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:

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HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube

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5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface

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10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes

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13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.

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4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system

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13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES

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7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6

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2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3

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Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5

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Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7

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Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS

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11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68

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15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT

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USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate

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assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The

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heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:

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1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2

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Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently

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5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm

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2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm

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7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100
0

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C
9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm

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11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A

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16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C

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19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter
V
Ammeter

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A
Main heater (
0
C) Test Plate (
0

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C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.

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Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.

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4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.

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4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?

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9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?

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14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?

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19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF

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PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus

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Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter

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(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm

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5. The effective length of the above = 500 mm

14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:

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1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W

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Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material

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k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.

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No.
Voltage
(V)
Current
(A)

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Heater Temperature
(
0
C)
Asbestos Temperature

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(
0
C)
Saw dust
Temperature (

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0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.

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2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.

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6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.

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The thermal conductivity of resistive material = _________________ W /m
2
-K

Outcome:

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From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:

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Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. Define ? Nusselt Number(Nu)

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2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)

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7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?

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12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?

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17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION

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FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The

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temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold

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fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Schematic view of the test set-up:
mm

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mm

19 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.

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5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A

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7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

Tabulation:

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Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m

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2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (

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0
C) ?
2. hL / k = A { g L
3
?T Cp ?/2v

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2
}
n

Where, hL / k are called Nusselt Number.

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L
3
g?T / v
2
is called Grashof number.

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?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid

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? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta

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For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)

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0.25
for 10
4
< Gr.Pr.<10
8

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hL / k = 0.13 (Gr.Pr)
1/3
for 10
8

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< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.

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4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as

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Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m
2

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K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC

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engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?

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6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?

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11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.

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16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to

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the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

Sl. No. Voltage Current Temperature in (
0

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C)
Manometer
reading of water
in h in meter

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(V) (A)
T1

T2

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T3

T4

T5

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T6

h1
cm

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h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer

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6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0
C
(Calibrated for chromel alumel thermocouple)

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8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.

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7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat

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input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)

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Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o
C)

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= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di

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2
?2gH x (?w / ?a) m
3
/hr
3. ha = qa /A(Ts- Ta) W / m

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2
K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

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Ta = Average temperature of air = (T1 + T6)/2
o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4

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o
C
Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m

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3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

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d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

using this procedure obtain the value of ?ha? for different air flow rate

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4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2
)/4]

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v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o
C
5. Nusselt Number:

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Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

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27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m

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2

k = Thermal conductivity of fluid W/m
2
K

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Nu = 0.023 (Re)
0.8
(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

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Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m

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2
K
htheoritical = -------------- W/m
2
K

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Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?

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4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?

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9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.

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14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

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29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

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Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the

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thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The

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temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is

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the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm

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3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat

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input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

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30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.

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7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow

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R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:

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Sl.No. Voltmeter
reading
(V)
Ammeter
reading

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(A)
T1
(
0
C)

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T2
(
0
C)
T3

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(
0
C)
T4
(

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0
C)
T5
(
0

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C)
T6
(
0
C)

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T7
(
0
C)
T8

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(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Composite wall apparatus set-up

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Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

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Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal

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conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?

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10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

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33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY

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OF INSULATING POWDER

Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

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The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit

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is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

Procedure:

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1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter

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reading( V)
Ammeter
reading (A)
T1
(

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0
C)
T2
(
0

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C)
T3
(
0
C)

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T4
(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1

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Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.


34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Fig. 1 Apparatus of thermal conductivity of insulating powder

[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater

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control]

Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

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Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to

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be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION

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MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex

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software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills

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4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning

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To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the

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career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society

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7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with

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coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:

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HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube

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5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface

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10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes

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13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.

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4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system

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13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES

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7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6

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2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3

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Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5

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Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7

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Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS

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11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68

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15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT

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USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate

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assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The

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heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:

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1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2

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Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

9 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently

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5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm

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2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm

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7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100
0

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C
9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm

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11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A

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16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C

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19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulation:
Sl. No. Voltmeter
V
Ammeter

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A
Main heater (
0
C) Test Plate (
0

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C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.

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Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.

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4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.

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4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?

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9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?

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14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?

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19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF

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PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus

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Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter

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(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm

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5. The effective length of the above = 500 mm

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Precautions:

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1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W

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Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material

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k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.

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No.
Voltage
(V)
Current
(A)

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Heater Temperature
(
0
C)
Asbestos Temperature

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(
0
C)
Saw dust
Temperature (

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0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.

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2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.

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6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.

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The thermal conductivity of resistive material = _________________ W /m
2
-K

Outcome:

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From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:

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Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. Define ? Nusselt Number(Nu)

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2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)

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7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?

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12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?

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17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION

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FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The

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temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold

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fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Schematic view of the test set-up:
mm

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mm

19 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.

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5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A

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7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

Tabulation:

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Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m

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2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (

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0
C) ?
2. hL / k = A { g L
3
?T Cp ?/2v

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2
}
n

Where, hL / k are called Nusselt Number.

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L
3
g?T / v
2
is called Grashof number.

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?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid

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? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta

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For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)

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0.25
for 10
4
< Gr.Pr.<10
8

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hL / k = 0.13 (Gr.Pr)
1/3
for 10
8

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< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.

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4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as

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Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m
2

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K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC

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engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?

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6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?

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11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.

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16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to

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the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

Sl. No. Voltage Current Temperature in (
0

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C)
Manometer
reading of water
in h in meter

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(V) (A)
T1

T2

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T3

T4

T5

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T6

h1
cm

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h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer

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6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0
C
(Calibrated for chromel alumel thermocouple)

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8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.

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7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat

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input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)

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Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o
C)

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= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di

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2
?2gH x (?w / ?a) m
3
/hr
3. ha = qa /A(Ts- Ta) W / m

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2
K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

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Ta = Average temperature of air = (T1 + T6)/2
o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4

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o
C
Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m

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3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

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d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

using this procedure obtain the value of ?ha? for different air flow rate

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4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2
)/4]

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v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o
C
5. Nusselt Number:

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Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

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27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m

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2

k = Thermal conductivity of fluid W/m
2
K

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Nu = 0.023 (Re)
0.8
(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

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Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m

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2
K
htheoritical = -------------- W/m
2
K

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Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?

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4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?

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9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.

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14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

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29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

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Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the

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thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The

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temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is

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the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm

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3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat

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input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

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30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.

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7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow

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R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:

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Sl.No. Voltmeter
reading
(V)
Ammeter
reading

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(A)
T1
(
0
C)

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T2
(
0
C)
T3

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(
0
C)
T4
(

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0
C)
T5
(
0

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C)
T6
(
0
C)

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T7
(
0
C)
T8

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(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Composite wall apparatus set-up

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Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

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Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal

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conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?

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10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

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33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY

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OF INSULATING POWDER

Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

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The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit

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is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

Procedure:

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1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter

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reading( V)
Ammeter
reading (A)
T1
(

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0
C)
T2
(
0

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C)
T3
(
0
C)

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T4
(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1

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Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.


34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Fig. 1 Apparatus of thermal conductivity of insulating powder

[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater

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control]

Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

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Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to

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be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?

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4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?

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9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)

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14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?

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19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

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FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________

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Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and

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enterprising professionals conforming to global standards through value based quality education and training.



? To provide competent technical manpower capable of meeting requirements of the industry

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? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING



Rendering the services to the global needs of engineering industries by educating students to become

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professionally sound mechanical engineers of excellent caliber



To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on

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experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION
MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould

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them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth

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To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up

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their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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PROGRAMME OUTCOMES (POs)

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On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications

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4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability

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8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills

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11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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ME6512 ? THERMAL ENGINEERING LABORATORY ? II



? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the

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performance of refrigeration cycle / components

LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus

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2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder

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7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

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REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System

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15. Performance test in a fluidized Bed Cooling Tower



1. Able to find out the thermal conductivity of various materials.

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2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials

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6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.

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11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures

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14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
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CONTENTS


Sl.No.
Name of the experiment

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Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe

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apparatus
11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder

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15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS

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6
Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39

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9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58

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13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS

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16 Air conditioning test rig 75
PROJECT WORK 81

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Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

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Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup

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(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to

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prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater

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assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved

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aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK

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3. Area, A = ( ?/4) d
2
(10 + x)

cm

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2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.

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2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there

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is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

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Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm

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4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40

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0
C ? 100
0
C
9. Maximum temperature of the hot plate = 170

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0
C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)

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13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)

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18. Temperature indicator = 0 ? 200
0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm

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21. Specimen used = Press wood

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Tabulation:

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Sl. No. Voltmeter
V
Ammeter
A
Main heater (

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0
C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water

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is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from

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thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably

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steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:

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Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded

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hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.

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6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer

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11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?

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16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

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Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup

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(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter
Theory:

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The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in

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the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:
1. Diameter of the heater Rod = 20 mm.

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2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).

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2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by

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Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging

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material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.
No.
Voltage

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(V)
Current
(A)
Heater Temperature
(

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0
C)
Asbestos Temperature
(
0

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C)
Saw dust
Temperature (
0
C)

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T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.

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4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.

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7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2

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-K

Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC

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engines, heat exchangers, etc. where heat transfer is to be found.

Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?

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4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?

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9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?

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14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis

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19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

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Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:
(i) Experimental setup

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(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at

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the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

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When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Schematic view of the test set-up:
mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm

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3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0

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C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V

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9. Heater = Cartridge type (400 W)

Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (

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0
c)

V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:

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1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2
K

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As = Area of heat transfer surface = ? x d x l m
2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0

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C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0
C) ?

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2. hL / k = A { g L
3
?T Cp ?/2v
2
}

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n

Where, hL / k are called Nusselt Number.
L
3

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g?T / v
2
is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.

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Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid

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? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0

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K
-1

Where Tf = (Ts + Ta )/ 2

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For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25
for 10

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4
< Gr.Pr.<10
8

hL / k = 0.13 (Gr.Pr)

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1/3
for 10
8
< Gr.Pr.<10
12

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Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

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Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2

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K
Experimental = ______________ W/ m
2
K

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Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?

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3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?

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8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer

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13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.

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18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No. 4

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

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Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:

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(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

Theory:

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Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat

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supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



Tabulations:

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Sl. No. Voltage Current Temperature in (
0
C)
Manometer

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reading of water
in h in meter

(V) (A)
T1

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T2

T3

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T4

T5

T6

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h1
cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm

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3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300

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0
C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A

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10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.

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4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:

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1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady

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state is reached.
4. Note down the heater input.

26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)

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?T = Temperature rise in air (
o
C)
= T6 ? T1.
2. m = Q?

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Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m

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3
/hr
3. ha = qa /A(Ts- Ta) W / m
2
K

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qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

Ta = Average temperature of air = (T1 + T6)/2

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o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C

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Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

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?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s

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2

using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number

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Where, V = velocity of air = Q/[(? x Di
2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2

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o
C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K

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Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

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k = Thermal conductivity of fluid W/m
2
K
Nu = 0.023 (Re)
0.8

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(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

Results:

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Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m
2
K

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htheoritical = -------------- W/m
2
K

Outcome:

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From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.

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6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?

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11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall

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Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The

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temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus

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uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.

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Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.

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Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.

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4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from

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the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate

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Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter
reading

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(V)
Ammeter
reading
(A)
T1

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(
0
C)
T2
(

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0
C)
T3
(
0

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C)
T4
(
0
C)

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T5
(
0
C)
T6

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(
0
C)
T7
(

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0
C)
T8
(
0

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C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:
The rate of heat transfer through different materials are found to be

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a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

Outcome:

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From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.



32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?

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3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.

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7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?

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12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

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Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between

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the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

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Procedure:

1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.

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3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter
reading( V)
Ammeter

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reading (A)
T1
(
0
C)

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T2
(
0
C)
T3

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(
0
C)
T4
(

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0
C)

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Calculations:

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The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Fig. 1 Apparatus of thermal conductivity of insulating powder

[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

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Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

Outcome:

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From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?

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6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?

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11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection

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16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.7

HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

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Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer
Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of

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the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:

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Forced convection:
Sl.
No.
V I

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Fin Temperatures (
0
C)
Ambient Temp
(

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0
C)
Manometer
Reading
(V)

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(A)

T1 T2 T3 T4 T5 T6 T7 T8
h1

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cm
h2
cm

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FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION

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MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex

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software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills

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4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning

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To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the

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career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society

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7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with

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coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:

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HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube

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5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface

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10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes

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13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.

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4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system

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13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES

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7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6

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2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3

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Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5

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Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7

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Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS

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11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68

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15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT

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USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate

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assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The

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heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:

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1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2

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Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently

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5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm

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2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm

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7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100
0

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C
9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm

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11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A

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16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C

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19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter
V
Ammeter

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A
Main heater (
0
C) Test Plate (
0

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C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.

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Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.

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4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.

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4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?

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9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?

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14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?

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19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF

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PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus

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Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter

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(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm

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5. The effective length of the above = 500 mm

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Precautions:

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1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W

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Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material

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k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.

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No.
Voltage
(V)
Current
(A)

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Heater Temperature
(
0
C)
Asbestos Temperature

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(
0
C)
Saw dust
Temperature (

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0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.

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2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.

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6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.

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The thermal conductivity of resistive material = _________________ W /m
2
-K

Outcome:

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From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:

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Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. Define ? Nusselt Number(Nu)

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2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)

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7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?

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12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?

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17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION

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FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The

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temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold

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fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Schematic view of the test set-up:
mm

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mm

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Specifications:

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1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.

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5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A

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7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

Tabulation:

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Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m

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2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (

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0
C) ?
2. hL / k = A { g L
3
?T Cp ?/2v

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2
}
n

Where, hL / k are called Nusselt Number.

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L
3
g?T / v
2
is called Grashof number.

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?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid

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? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta

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For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)

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0.25
for 10
4
< Gr.Pr.<10
8

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hL / k = 0.13 (Gr.Pr)
1/3
for 10
8

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< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.

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4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as

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Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m
2

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K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC

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engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?

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6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?

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11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.

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16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to

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the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

Sl. No. Voltage Current Temperature in (
0

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C)
Manometer
reading of water
in h in meter

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(V) (A)
T1

T2

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T3

T4

T5

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T6

h1
cm

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h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer

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6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0
C
(Calibrated for chromel alumel thermocouple)

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8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.

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7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat

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input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)

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Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o
C)

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= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di

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2
?2gH x (?w / ?a) m
3
/hr
3. ha = qa /A(Ts- Ta) W / m

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2
K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

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Ta = Average temperature of air = (T1 + T6)/2
o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4

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o
C
Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m

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3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

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d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

using this procedure obtain the value of ?ha? for different air flow rate

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4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2
)/4]

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v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o
C
5. Nusselt Number:

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Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

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27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m

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2

k = Thermal conductivity of fluid W/m
2
K

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Nu = 0.023 (Re)
0.8
(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

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Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m

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2
K
htheoritical = -------------- W/m
2
K

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Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?

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4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?

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9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.

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14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

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29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

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Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the

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thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The

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temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is

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the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm

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3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat

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input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

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30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.

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7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow

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R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:

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Sl.No. Voltmeter
reading
(V)
Ammeter
reading

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(A)
T1
(
0
C)

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T2
(
0
C)
T3

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(
0
C)
T4
(

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0
C)
T5
(
0

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C)
T6
(
0
C)

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T7
(
0
C)
T8

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(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Composite wall apparatus set-up

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Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

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Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal

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conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?

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10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

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33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY

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OF INSULATING POWDER

Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

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The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit

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is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

Procedure:

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1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter

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reading( V)
Ammeter
reading (A)
T1
(

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0
C)
T2
(
0

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C)
T3
(
0
C)

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T4
(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1

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Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.


34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Fig. 1 Apparatus of thermal conductivity of insulating powder

[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater

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control]

Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

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Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to

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be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?

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4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?

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9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)

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14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?

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19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

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36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

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HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:

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A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is

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shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:
Sl.
No.

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V I

Fin Temperatures (
0
C)

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Ambient Temp
(
0
C)
Manometer

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Reading
(V)

(A)

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T1 T2 T3 T4 T5 T6 T7 T8
h1
cm
h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm

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3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.

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11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C
12. Temperature indicator = 0 ? 300
0

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C
(With compensation of ambient temperature up-to 50
0
C)
13. Dimmer stat for heat input controls 230 V, 2 A

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14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8
Brass Pin Fin

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Heater
FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?



DEPARTMENT OF

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MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

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Name : _______________________________________

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Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION
MISSION

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4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals

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To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them

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3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills

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To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering

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and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME OUTCOMES (POs)

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On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship

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3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical

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environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination

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10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:

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1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall

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6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

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REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor

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14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus

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5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.

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10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at

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various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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CONTENTS


Sl.No.

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Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2

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Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3
Determination of heat transfer coefficient under natural convection from a

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vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27

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CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34

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8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51

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12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72

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ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

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Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:

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(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:

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The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.

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Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts

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on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:
1. Power input, Q = V ? A / 2 W

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2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:

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1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do

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not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm

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3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm

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8. Mean temperature range = 40
0
C ? 100
0
C

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9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)

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12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)

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17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C
19. Width of gap between two heater plates (x) = 2.5 mm

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20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter
V
Ammeter
A

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Main heater (
0
C) Test Plate (
0
C)

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T1 T2 T3 T4 T5 T6



Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.

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2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.

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5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

Outcome:

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From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

Applications:

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Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins

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5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?

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10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?

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15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?

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20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE

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APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:

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(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter

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Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:

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1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the

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experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:

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The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.

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L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.
No.

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Voltage
(V)
Current
(A)
Heater Temperature

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(
0
C)
Asbestos Temperature
(

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0
C)
Saw dust
Temperature (
0

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C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.

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3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by

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thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m

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2
-K

Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe

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apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?

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3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection

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8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?

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13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?

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18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

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Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:

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(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:

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The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is

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measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the

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relative motion of hot and cold fluid particles.

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Schematic view of the test set-up:
mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm

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2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300

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0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V

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8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

Tabulation:
Sl. No.

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Voltage Current Temperature of Thermocouple (
0
c)

V A

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T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2

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K
As = Area of heat transfer surface = ? x d x l m
2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7

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0
C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0

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C) ?
2. hL / k = A { g L
3
?T Cp ?/2v
2

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}
n

Where, hL / k are called Nusselt Number.
L

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3
g?T / v
2
is called Grashof number.
?Cp / k called Prandtl Number.

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A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid

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Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)

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0
K
-1

Where Tf = (Ts + Ta )/ 2

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For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25

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for 10
4
< Gr.Pr.<10
8

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hL / k = 0.13 (Gr.Pr)
1/3
for 10
8
< Gr.Pr.<10

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12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).

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5. Repeat the experiment at different heat inputs.

Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m

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2
K
Experimental = ______________ W/ m
2
K

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Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be

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found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)

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2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness

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7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?

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12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.

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17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No. 4

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION

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FROM A TUBE

Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater

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is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

Sl. No. Voltage Current Temperature in (
0
C)

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Manometer
reading of water
in h in meter

(V) (A)

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T1

T2

T3

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T4

T5

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T6

h1
cm
h2

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cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Pipe diameter outside (Do) = 40 mm

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2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C

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7. Temperature Indicator = Range 0 to 300
0
C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V

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9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.

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3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W

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Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.

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3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)

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Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o
C)
= T6 ? T1.

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2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di
2

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?2gH x (?w / ?a) m
3
/hr
3. ha = qa /A(Ts- Ta) W / m
2

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K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

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Ta = Average temperature of air = (T1 + T6)/2
o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o

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C
Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

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?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

d = diameter of orifice meter = 0.014 m

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g = acceleration due to gravity = 9.81 m/s
2

using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:

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Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature

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(T1 + T6)/2
o
C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number

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K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

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k = Thermal conductivity of fluid W/m
2
K
Nu = 0.023 (Re)

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0.8
(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

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Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m
2

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K
htheoritical = -------------- W/m
2
K

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Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.

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5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.

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10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?

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15. Define ? Momentum Thickness

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Viva ? voce

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29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:

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To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different

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materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A

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channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in

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series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm

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4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.

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3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

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plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as

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Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3

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Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter

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reading
(V)
Ammeter
reading
(A)

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T1
(
0
C)
T2

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(
0
C)
T3
(

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0
C)
T4
(
0

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C)
T5
(
0
C)

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T6
(
0
C)
T7

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(
0
C)
T8
(

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0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:

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The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

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Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. Define ? Heat Transfer

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2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?

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6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?
10. Define ? Heat Exchanger

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11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

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Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

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The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input

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power and dimmer stat is provided to vary the input power.

Procedure:

1. Switch on the unit and adjust the input power to the required extent.

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2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter
reading( V)

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Ammeter
reading (A)
T1
(
0

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C)
T2
(
0
C)

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T3
(
0
C)
T4

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(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the

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inner sphere, and the outer sphere respectively.


34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Fig. 1 Apparatus of thermal conductivity of insulating powder

[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

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Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

Outcome:

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From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?

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5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?

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10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)

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15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?

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20. What is meant by steady state heat conduction?

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Viva ? voce

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36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

HEAT TRANSFER FROM PIN-FIN APPARATUS

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(NATURAL AND FORCED CONVECTION MODES)

Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:

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(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is

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connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.

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Tabulations:
Forced convection:
Sl.
No.
V I

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Fin Temperatures (
0
C)
Ambient Temp

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(
0
C)
Manometer
Reading

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(V)

(A)

T1 T2 T3 T4 T5 T6 T7 T8

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h1
cm
h2
cm

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Specifications:
1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm

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4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm

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7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.

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0
C
12. Temperature indicator = 0 ? 300
0
C

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(With compensation of ambient temperature up-to 50
0
C)
13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)

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15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8
Brass Pin Fin
Heater

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38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

16. Ammeter = 0 ? 2 A
Precautions:

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1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.

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6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:
Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,

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100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.

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5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)

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2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m
3
/s.

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Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m
3

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?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s
2

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Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s
Where Q = discharge of air
FirstRanker.com - FirstRanker's Choice

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1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL

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2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels

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? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION

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MISSION
VISION
MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals

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2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which

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enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt

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and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able

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1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution

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5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both

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verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus

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3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)

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8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:

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11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus

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3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction

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7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-

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efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.

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15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.

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CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus

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11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15

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4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6

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Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43

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10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63

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14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75

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PROJECT WORK 81

8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:

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To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in

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which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.

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Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d

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2
(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.

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4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

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Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm

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5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0

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C ? 100
0
C
9. Maximum temperature of the hot plate = 170
0

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C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V

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14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200

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0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter

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V
Ammeter
A
Main heater (
0

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C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.

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3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.

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7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be

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k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat

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exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity

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2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?

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7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.

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12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.

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17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

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Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus

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(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is

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transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside

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an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm

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3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.

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3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)

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Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found

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Tabulation:
Sl.
No.
Voltage
(V)

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Current
(A)
Heater Temperature
(
0

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C)
Asbestos Temperature
(
0
C)

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Saw dust
Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.

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5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.

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Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?

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5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?

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10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow

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15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.

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20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:

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To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of

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the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

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When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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Schematic view of the test set-up:
mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm

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4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel

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thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0

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c)

V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Heat transfer coefficient is given by

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h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m

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2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C

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q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L

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3
?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v

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2
is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface

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K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid

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G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K

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-1

Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been

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determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25
for 10
4

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< Gr.Pr.<10
8

hL / k = 0.13 (Gr.Pr)
1/3

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for 10
8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.

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2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

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Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K

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Experimental = ______________ W/ m
2
K

Outcomes:

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From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.

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4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.

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9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?

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14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness

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19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

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Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer

Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band

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heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to

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measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.


24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

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Sl. No. Voltage Current Temperature in (
0
C)
Manometer
reading of water

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in h in meter

(V) (A)
T1

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T2

T3

T4

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T5

T6

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h1
cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm

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4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0

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C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.

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5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference

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in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.

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4. Note down the heater input.

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Formulae used:

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1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (

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o
C)
= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr

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Q = Volume flow rate
Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m
3

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/hr
3. ha = qa /A(Ts- Ta) W / m
2
K
qa = Rate of which air is getting heated.

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A = Test section area = ? x Di x L m
2

Ta = Average temperature of air = (T1 + T6)/2
o

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C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C
Cd = 0.64

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H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m

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3

d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

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using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di

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2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o

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C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings

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6. Prandtl Number:

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Pr = Cp? / k

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Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

k = Thermal conductivity of fluid W/m

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2
K
Nu = 0.023 (Re)
0.8
(Pr)

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0.4
Bulk mean temperature = (T1 + T6)/2

Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection

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apparatus.
hactual = -------------- W/m
2
K
htheoritical = -------------- W/m

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2
K

Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection

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apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is meant by boiling and condensation?

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2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?

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7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?

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12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:

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When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly

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temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The

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apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:

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1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:

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1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.

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5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)

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6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.

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Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities

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Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter
reading
(V)

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Ammeter
reading
(A)
T1
(

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0
C)
T2
(
0

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C)
T3
(
0
C)

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T4
(
0
C)
T5

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(
0
C)
T6
(

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0
C)
T7
(
0

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C)
T8
(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W

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b. Wood section = ---------------W
c. Asbestos section = ------------W

Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt

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and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.

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4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.

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8. Explain the significance of Fourier number.
9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

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DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

Aim:

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To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and

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T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

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Procedure:

1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.

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4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.


The readings are tabulated below

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Sl.No. Voltmeter
reading( V)
Ammeter
reading (A)

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T1
(
0
C)
T2

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(
0
C)
T3
(

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0
C)
T4
(
0

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C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm

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The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Fig. 1 Apparatus of thermal conductivity of insulating powder

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[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

Result:

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The thermal conductivity of insulating powder by conduction is found and the result is, ___________

Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is

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analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is the need for conducting this experiment?

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2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.

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7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?

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12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?

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17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.7

HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

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Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer
Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the

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fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:

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Sl.
No.
V I

Fin Temperatures (

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0
C)
Ambient Temp
(
0

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C)
Manometer
Reading
(V)

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(A)

T1 T2 T3 T4 T5 T6 T7 T8
h1
cm

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h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

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Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor

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9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C

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12. Temperature indicator = 0 ? 300
0
C
(With compensation of ambient temperature up-to 50
0

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C)
13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1

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T8
Brass Pin Fin
Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.

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3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.

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Procedure:
Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.

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3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)

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1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2

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) /4}?2gha m
3
/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m

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?w Density of water = 1000 kg/m
3

?a = Density of air = 1.165 kg/m
3

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g = acceleration due to gravity = 9.81 m/s
2

Cd = Coefficient of discharge = 0.64
D = diameter of the orifice

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3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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A = area of the duct
4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin

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v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2
o
C
5. Heat transfer coefficient, h = Nu k / D

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Where Nu = Nusselt Number
6. Nusselt Number:
Nu = CRe
m
(Pr)

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0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk

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m= ?(hp/kA)
A = area of fin = (? x D
2
) /4
L = Length of the fin

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Tw ? average temperature
T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were

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Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced

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convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.

FirstRanker.com - FirstRanker's Choice

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1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL

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2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels

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? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION

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MISSION
VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals

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2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which

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enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt

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and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able

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1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution

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5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both

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verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus

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3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)

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8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:

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11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus

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3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction

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7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-

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efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.

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15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.

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CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus

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11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15

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4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6

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Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43

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10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63

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14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75

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PROJECT WORK 81

8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:

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To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in

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which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.

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Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d

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2
(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.

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4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

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Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm

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5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0

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C ? 100
0
C
9. Maximum temperature of the hot plate = 170
0

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C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V

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14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200

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0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:
Sl. No. Voltmeter

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V
Ammeter
A
Main heater (
0

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C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.

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3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.

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7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be

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k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat

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exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity

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2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?

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7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.

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12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.

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17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

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Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus

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(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is

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transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside

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an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm

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3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.

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3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)

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Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found

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Tabulation:
Sl.
No.
Voltage
(V)

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Current
(A)
Heater Temperature
(
0

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C)
Asbestos Temperature
(
0
C)

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Saw dust
Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.

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5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.

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Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?

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5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?

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10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow

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15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.

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20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:

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To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of

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the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

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When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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Schematic view of the test set-up:
mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm

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4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel

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thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0

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c)

V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Heat transfer coefficient is given by

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h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m

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2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C

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q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L

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3
?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v

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2
is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface

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K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid

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G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K

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-1

Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been

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determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25
for 10
4

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< Gr.Pr.<10
8

hL / k = 0.13 (Gr.Pr)
1/3

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for 10
8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.

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2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

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Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K

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Experimental = ______________ W/ m
2
K

Outcomes:

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From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.

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4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.

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9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?

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14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness

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19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

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Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer

Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band

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heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to

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measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.


24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

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Sl. No. Voltage Current Temperature in (
0
C)
Manometer
reading of water

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in h in meter

(V) (A)
T1

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T2

T3

T4

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T5

T6

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h1
cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm

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4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0

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C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.

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5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference

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in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.

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4. Note down the heater input.

26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:

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1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (

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o
C)
= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr

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Q = Volume flow rate
Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m
3

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/hr
3. ha = qa /A(Ts- Ta) W / m
2
K
qa = Rate of which air is getting heated.

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A = Test section area = ? x Di x L m
2

Ta = Average temperature of air = (T1 + T6)/2
o

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C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C
Cd = 0.64

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H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m

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3

d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

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using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di

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2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o

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C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings

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6. Prandtl Number:

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Pr = Cp? / k

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Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

k = Thermal conductivity of fluid W/m

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2
K
Nu = 0.023 (Re)
0.8
(Pr)

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0.4
Bulk mean temperature = (T1 + T6)/2

Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection

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apparatus.
hactual = -------------- W/m
2
K
htheoritical = -------------- W/m

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2
K

Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection

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apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is meant by boiling and condensation?

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2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?

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7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?

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12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:

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When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly

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temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The

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apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:

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1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:

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1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.

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5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)

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6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.

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Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities

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Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter
reading
(V)

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Ammeter
reading
(A)
T1
(

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0
C)
T2
(
0

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C)
T3
(
0
C)

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T4
(
0
C)
T5

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(
0
C)
T6
(

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0
C)
T7
(
0

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C)
T8
(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W

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b. Wood section = ---------------W
c. Asbestos section = ------------W

Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt

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and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.

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4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.

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8. Explain the significance of Fourier number.
9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

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DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

Aim:

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To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and

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T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

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Procedure:

1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.

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4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.


The readings are tabulated below

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Sl.No. Voltmeter
reading( V)
Ammeter
reading (A)

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T1
(
0
C)
T2

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(
0
C)
T3
(

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0
C)
T4
(
0

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C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm

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The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Fig. 1 Apparatus of thermal conductivity of insulating powder

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[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

Result:

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The thermal conductivity of insulating powder by conduction is found and the result is, ___________

Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is

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analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is the need for conducting this experiment?

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2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.

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7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?

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12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?

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17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.7

HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

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Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer
Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the

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fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:

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Sl.
No.
V I

Fin Temperatures (

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0
C)
Ambient Temp
(
0

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C)
Manometer
Reading
(V)

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(A)

T1 T2 T3 T4 T5 T6 T7 T8
h1
cm

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h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

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Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor

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9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C

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12. Temperature indicator = 0 ? 300
0
C
(With compensation of ambient temperature up-to 50
0

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C)
13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1

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T8
Brass Pin Fin
Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.

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3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.

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Procedure:
Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.

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3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)

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1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2

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) /4}?2gha m
3
/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m

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?w Density of water = 1000 kg/m
3

?a = Density of air = 1.165 kg/m
3

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g = acceleration due to gravity = 9.81 m/s
2

Cd = Coefficient of discharge = 0.64
D = diameter of the orifice

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3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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A = area of the duct
4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin

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v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2
o
C
5. Heat transfer coefficient, h = Nu k / D

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Where Nu = Nusselt Number
6. Nusselt Number:
Nu = CRe
m
(Pr)

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0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk

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m= ?(hp/kA)
A = area of fin = (? x D
2
) /4
L = Length of the fin

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Tw ? average temperature
T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were

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Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced

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convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.

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40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?

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5. Define ? Heat Transfer
6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?

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10. What is meant by steady state heat conduction?
11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number

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15. Give the expression for calculating velocity of air.

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Viva ? voce
FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION

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MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex

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software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills

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4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning

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To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the

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career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society

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7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with

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coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:

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HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube

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5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface

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10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes

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13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.

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4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system

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13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES

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7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6

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2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3

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Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5

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Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7

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Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS

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11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68

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15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT

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USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate

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assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The

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heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:

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1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2

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Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

9 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently

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5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm

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2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm

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7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100
0

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C
9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm

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11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A

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16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C

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19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulation:
Sl. No. Voltmeter
V
Ammeter

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A
Main heater (
0
C) Test Plate (
0

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C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.

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Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.

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4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.

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4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?

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9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?

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14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?

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19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF

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PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus

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Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter

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(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm

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5. The effective length of the above = 500 mm

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Precautions:

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1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W

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Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material

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k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.

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No.
Voltage
(V)
Current
(A)

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Heater Temperature
(
0
C)
Asbestos Temperature

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(
0
C)
Saw dust
Temperature (

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0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.

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2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.

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6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.

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The thermal conductivity of resistive material = _________________ W /m
2
-K

Outcome:

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From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:

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Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. Define ? Nusselt Number(Nu)

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2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)

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7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?

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12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?

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17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION

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FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The

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temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold

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fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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Schematic view of the test set-up:
mm

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mm

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Specifications:

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1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.

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5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A

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7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

Tabulation:

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Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m

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2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (

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0
C) ?
2. hL / k = A { g L
3
?T Cp ?/2v

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2
}
n

Where, hL / k are called Nusselt Number.

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L
3
g?T / v
2
is called Grashof number.

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?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid

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? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta

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For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)

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0.25
for 10
4
< Gr.Pr.<10
8

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hL / k = 0.13 (Gr.Pr)
1/3
for 10
8

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< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.

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4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as

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Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m
2

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K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC

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engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?

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6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?

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11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.

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16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to

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the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

Sl. No. Voltage Current Temperature in (
0

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C)
Manometer
reading of water
in h in meter

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(V) (A)
T1

T2

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T3

T4

T5

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T6

h1
cm

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h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer

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6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0
C
(Calibrated for chromel alumel thermocouple)

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8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.

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7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat

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input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)

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Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o
C)

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= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di

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2
?2gH x (?w / ?a) m
3
/hr
3. ha = qa /A(Ts- Ta) W / m

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2
K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

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Ta = Average temperature of air = (T1 + T6)/2
o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4

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o
C
Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m

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3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

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d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

using this procedure obtain the value of ?ha? for different air flow rate

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4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2
)/4]

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v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o
C
5. Nusselt Number:

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Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

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27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m

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2

k = Thermal conductivity of fluid W/m
2
K

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Nu = 0.023 (Re)
0.8
(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

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Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m

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2
K
htheoritical = -------------- W/m
2
K

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Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?

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4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?

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9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.

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14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

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29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

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Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the

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thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The

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temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is

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the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm

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3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat

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input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

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30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.

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7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow

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R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:

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Sl.No. Voltmeter
reading
(V)
Ammeter
reading

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(A)
T1
(
0
C)

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T2
(
0
C)
T3

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(
0
C)
T4
(

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0
C)
T5
(
0

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C)
T6
(
0
C)

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T7
(
0
C)
T8

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(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Composite wall apparatus set-up

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Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

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Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal

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conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?

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10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

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33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY

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OF INSULATING POWDER

Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

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The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit

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is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

Procedure:

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1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter

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reading( V)
Ammeter
reading (A)
T1
(

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0
C)
T2
(
0

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C)
T3
(
0
C)

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T4
(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1

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Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.


34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Fig. 1 Apparatus of thermal conductivity of insulating powder

[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater

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control]

Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

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Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to

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be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?

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4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?

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9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)

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14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?

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19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

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36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

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HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:

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A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is

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shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:
Sl.
No.

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V I

Fin Temperatures (
0
C)

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Ambient Temp
(
0
C)
Manometer

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Reading
(V)

(A)

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T1 T2 T3 T4 T5 T6 T7 T8
h1
cm
h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm

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3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.

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11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C
12. Temperature indicator = 0 ? 300
0

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C
(With compensation of ambient temperature up-to 50
0
C)
13. Dimmer stat for heat input controls 230 V, 2 A

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14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8
Brass Pin Fin

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Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

16. Ammeter = 0 ? 2 A

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.

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5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:
Forced Convection:

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1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient

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temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)

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Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m
3

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/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m
3

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?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s
2

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Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

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39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

A = area of the duct
4. Reynold?s Number:

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Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2

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o
C
5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number
6. Nusselt Number:

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Nu = CRe
m
(Pr)
0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)

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h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk
m= ?(hp/kA)
A = area of fin = (? x D

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2
) /4
L = Length of the fin
Tw ? average temperature
T? ? ambient (surface) temperature (T6)

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8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

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Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through

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pin-fin is to be found.


40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Extended Surface

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2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer
6. Define ? Fin Efficiency

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7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?
11. Define ? Convection

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12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

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41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.8

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DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus

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Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Geyser water

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Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to

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measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response

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of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm

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4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg

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0
C
= (or) 0.1 Kcal / kg
0
C

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9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.
FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION

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MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex

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software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills

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4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning

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To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the

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career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society

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7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with

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coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:

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HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube

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5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface

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10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes

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13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.

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4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system

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13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES

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7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6

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2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3

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Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5

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Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7

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Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS

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11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68

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15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT

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USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate

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assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The

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heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:

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1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2

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Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

9 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently

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5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm

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2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm

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7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100
0

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C
9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm

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11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A

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16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C

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19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter
V
Ammeter

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A
Main heater (
0
C) Test Plate (
0

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C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.

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Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.

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4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.

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4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?

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9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?

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14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?

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19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF

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PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus

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Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter

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(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm

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5. The effective length of the above = 500 mm

14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:

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1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W

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Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material

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k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.

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No.
Voltage
(V)
Current
(A)

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Heater Temperature
(
0
C)
Asbestos Temperature

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(
0
C)
Saw dust
Temperature (

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0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.

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2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.

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6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.

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The thermal conductivity of resistive material = _________________ W /m
2
-K

Outcome:

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From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:

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Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. Define ? Nusselt Number(Nu)

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2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)

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7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?

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12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?

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17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION

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FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The

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temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold

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fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Schematic view of the test set-up:
mm

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mm

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Specifications:

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1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.

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5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A

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7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

Tabulation:

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Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m

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2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (

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0
C) ?
2. hL / k = A { g L
3
?T Cp ?/2v

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2
}
n

Where, hL / k are called Nusselt Number.

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L
3
g?T / v
2
is called Grashof number.

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?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid

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? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta

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For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)

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0.25
for 10
4
< Gr.Pr.<10
8

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hL / k = 0.13 (Gr.Pr)
1/3
for 10
8

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< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.

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4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as

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Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m
2

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K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC

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engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?

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6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?

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11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.

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16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to

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the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

Sl. No. Voltage Current Temperature in (
0

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C)
Manometer
reading of water
in h in meter

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(V) (A)
T1

T2

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T3

T4

T5

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T6

h1
cm

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h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer

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6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0
C
(Calibrated for chromel alumel thermocouple)

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8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.

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7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat

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input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)

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Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o
C)

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= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di

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2
?2gH x (?w / ?a) m
3
/hr
3. ha = qa /A(Ts- Ta) W / m

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2
K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

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Ta = Average temperature of air = (T1 + T6)/2
o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4

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o
C
Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m

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3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

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d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

using this procedure obtain the value of ?ha? for different air flow rate

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4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2
)/4]

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v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o
C
5. Nusselt Number:

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Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

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27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m

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2

k = Thermal conductivity of fluid W/m
2
K

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Nu = 0.023 (Re)
0.8
(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

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Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m

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2
K
htheoritical = -------------- W/m
2
K

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Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?

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4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?

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9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.

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14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

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29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

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Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the

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thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The

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temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is

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the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm

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3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat

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input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

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30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.

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7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow

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R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:

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Sl.No. Voltmeter
reading
(V)
Ammeter
reading

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(A)
T1
(
0
C)

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T2
(
0
C)
T3

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(
0
C)
T4
(

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0
C)
T5
(
0

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C)
T6
(
0
C)

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T7
(
0
C)
T8

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(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Composite wall apparatus set-up

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Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

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Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal

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conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?

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10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

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33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY

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OF INSULATING POWDER

Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

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The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit

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is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

Procedure:

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1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter

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reading( V)
Ammeter
reading (A)
T1
(

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0
C)
T2
(
0

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C)
T3
(
0
C)

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T4
(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1

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Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.


34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Fig. 1 Apparatus of thermal conductivity of insulating powder

[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater

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control]

Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

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Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to

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be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?

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4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?

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9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)

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14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?

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19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

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36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

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HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:

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A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is

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shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:
Sl.
No.

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V I

Fin Temperatures (
0
C)

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Ambient Temp
(
0
C)
Manometer

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Reading
(V)

(A)

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T1 T2 T3 T4 T5 T6 T7 T8
h1
cm
h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm

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3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.

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11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C
12. Temperature indicator = 0 ? 300
0

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C
(With compensation of ambient temperature up-to 50
0
C)
13. Dimmer stat for heat input controls 230 V, 2 A

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14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8
Brass Pin Fin

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Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

16. Ammeter = 0 ? 2 A

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.

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5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:
Forced Convection:

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1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient

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temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)

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Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m
3

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/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m
3

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?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s
2

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Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

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39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

A = area of the duct
4. Reynold?s Number:

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Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2

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o
C
5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number
6. Nusselt Number:

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Nu = CRe
m
(Pr)
0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)

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h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk
m= ?(hp/kA)
A = area of fin = (? x D

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2
) /4
L = Length of the fin
Tw ? average temperature
T? ? ambient (surface) temperature (T6)

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8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

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Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through

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pin-fin is to be found.


40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Extended Surface

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2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer
6. Define ? Fin Efficiency

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7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?
11. Define ? Convection

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12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

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41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.8

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DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus

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Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Geyser water

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Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to

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measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response

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of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm

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4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg

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0
C
= (or) 0.1 Kcal / kg
0
C

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9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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11. Temperature indicator digital 0.1
0
C L.C 0 - 200
0
C with built-in cold junction compensation and a timer set

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for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically

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there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4
? Td

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4
)
Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0

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dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater
FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart

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and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION

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VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence

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To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design

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products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies

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5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering

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2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools

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6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms

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9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder

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4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant

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9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system

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12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection

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experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.

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12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC

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Boiler.



COURSE OBJECTIVES

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COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS

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1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11

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3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21

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5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31

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7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47

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CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14

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Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate

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method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters

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together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples

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No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2

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(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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9 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help

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of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:

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1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm

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6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100

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0
C
9. Maximum temperature of the hot plate = 170
0
C

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10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V

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15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0

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C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter
V

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Ammeter
A
Main heater (
0
C) Test Plate (

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0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:

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1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single

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phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.

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8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.

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3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?

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8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?

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13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?

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18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:

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To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple

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(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.

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There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.

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4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.

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4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging

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k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:

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Sl.
No.
Voltage
(V)
Current

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(A)
Heater Temperature
(
0
C)

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Asbestos Temperature
(
0
C)
Saw dust

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Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos

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layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:

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The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)

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6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?

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11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.

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16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical

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tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which

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in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.

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The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Schematic view of the test set-up:

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mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch

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Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples

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6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}

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Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W

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Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L
3

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?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v
2

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is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid

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v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity

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?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.

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hL / k = 0.56 (Gr.Pr)
0.25
for 10
4
< Gr.Pr.<10

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8

hL / k = 0.13 (Gr.Pr)
1/3
for 10

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8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).

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3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:

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The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m

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2
K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing

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heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?

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5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)

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10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness

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15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?

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20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:

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To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer

Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air

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stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of

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orifice meter and the water manometer fitted on the board.


24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

Sl. No. Voltage Current Temperature in (

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0
C)
Manometer
reading of water
in h in meter

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(V) (A)
T1

T2

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T3

T4

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T5

T6

h1

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cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor

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5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0
C

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(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:

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1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.

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6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.

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2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. The rate at which air is getting heated is calculated as

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qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o

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C)
= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate

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Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m
3
/hr

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3. ha = qa /A(Ts- Ta) W / m
2
K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m

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2

Ta = Average temperature of air = (T1 + T6)/2
o
C

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Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C
Cd = 0.64
H = Difference of water level in manometer m

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?w Density of water = 1000 Kg/m
3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

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d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

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using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2

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)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o
C

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5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

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27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k

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? = Viscosity Ns/m
2

k = Thermal conductivity of fluid W/m
2

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K
Nu = 0.023 (Re)
0.8
(Pr)
0.4

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Bulk mean temperature = (T1 + T6)/2

Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.

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hactual = -------------- W/m
2
K
htheoritical = -------------- W/m
2

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K

Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?

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3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?

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8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection

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13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

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Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,

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the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure

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temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat

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flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm

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2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.

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2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

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30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature

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gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:

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Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R

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Tabulation:
Sl.No. Voltmeter
reading
(V)
Ammeter

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reading
(A)
T1
(
0

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C)
T2
(
0
C)

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T3
(
0
C)
T4

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(
0
C)
T5
(

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0
C)
T6
(
0

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C)
T7
(
0
C)

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T8
(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Composite wall apparatus set-up

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Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W

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c. Asbestos section = ------------W

Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure

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Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?

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5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.

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9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

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33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

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DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

Aim:
To find out the thermal conductivity of insulating powder by conduction

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Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A

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multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

Procedure:

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1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.

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5. Repeat the experiments for different power inputs.


The readings are tabulated below

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Sl.No. Voltmeter
reading( V)
Ammeter
reading (A)
T1

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(
0
C)
T2
(

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0
C)
T3
(
0

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C)
T4
(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm

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The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Fig. 1 Apparatus of thermal conductivity of insulating powder

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[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

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Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam

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boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity

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3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.

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8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?

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13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?

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18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

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HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

Aim:

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To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is

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measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:
Sl.

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No.
V I

Fin Temperatures (
0

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C)
Ambient Temp
(
0
C)

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Manometer
Reading
(V)

(A)

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T1 T2 T3 T4 T5 T6 T7 T8
h1
cm
h2

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cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Duct size = 150 mm x 100 mm.

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2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

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Schematic view of the test set-up:



zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5

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10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C
12. Temperature indicator = 0 ? 300

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0
C
(With compensation of ambient temperature up-to 50
0
C)

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13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8

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Brass Pin Fin
Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.

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4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:

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Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.

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4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2

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Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m

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3
/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m

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3

?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s

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2

Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s

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Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

A = area of the duct

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4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.

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(T1 + T6) / 2
o
C
5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number

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6. Nusselt Number:
Nu = CRe
m
(Pr)
0.33

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7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk
m= ?(hp/kA)

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A = area of fin = (? x D
2
) /4
L = Length of the fin
Tw ? average temperature

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T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________

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Heat transfer, Q = ___________ W

Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.


40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer

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6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?

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11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.8

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DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

Aim:

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To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch

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(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water

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between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.

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When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere

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3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg

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8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C
= (or) 0.1 Kcal / kg
0

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C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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11. Temperature indicator digital 0.1
0
C L.C 0 - 200
0

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C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water
Precautions:

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Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4

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? Td
4
)
Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)

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Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

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43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulations:
Proc
edur

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e:
1. H
eat the
water
in the

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tank by
the immersion heater up to a temperature of about 90
0
C.
2. Remove the disc, D before pouring the hot water in the jacket.

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3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.

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6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m

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2
k
4
.

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Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using

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boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

Sl. No.

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Hemisphere Temperature(
0
C) Avg. Temp.
of the
Hemisphere

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(Th)
T4
Steady
Temp. of
Disc

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T0 (Td)
Time
(Sec) T1 T2 T3

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FirstRanker.com - FirstRanker's Choice

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1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels

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? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION

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MISSION
VISION
MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals

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2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which

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enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt

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and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able

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1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution

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5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both

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verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus

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3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)

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8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:

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11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus

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3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction

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7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-

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efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.

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15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
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CONTENTS

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Sl.No.
Name of the experiment
Page No.

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CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus

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11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15

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4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6

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Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43

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10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63

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14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75

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PROJECT WORK 81

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Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:

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To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in

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which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.

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Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d

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2
(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.

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4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

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Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm

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5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0

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C ? 100
0
C
9. Maximum temperature of the hot plate = 170
0

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C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V

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14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200

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0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter

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V
Ammeter
A
Main heater (
0

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C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.

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3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.

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7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be

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k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat

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exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

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1. Define ? Thermal Conductivity

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2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?

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7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.

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12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.

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17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

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Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus

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(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is

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transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside

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an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm

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3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.

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3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)

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Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found

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Tabulation:
Sl.
No.
Voltage
(V)

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Current
(A)
Heater Temperature
(
0

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C)
Asbestos Temperature
(
0
C)

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Saw dust
Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.

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5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.

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Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?

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5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?

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10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow

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15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.

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20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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Expt. No.3

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:

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To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of

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the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

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When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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Schematic view of the test set-up:
mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm

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4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel

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thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0

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c)

V A
T1 T2 T3 T4 T5 T6

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Formulae used:
1. Heat transfer coefficient is given by

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h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m

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2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C

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q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L

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3
?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v

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2
is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface

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K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid

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G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K

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-1

Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been

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determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25
for 10
4

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< Gr.Pr.<10
8

hL / k = 0.13 (Gr.Pr)
1/3

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for 10
8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.

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2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

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Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K

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Experimental = ______________ W/ m
2
K

Outcomes:

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From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.

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4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.

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9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?

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14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness

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19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

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Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer

Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band

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heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to

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measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.


24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

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Sl. No. Voltage Current Temperature in (
0
C)
Manometer
reading of water

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in h in meter

(V) (A)
T1

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T2

T3

T4

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T5

T6

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h1
cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm

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4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0

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C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.

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5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference

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in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.

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4. Note down the heater input.

26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:

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1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (

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o
C)
= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr

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Q = Volume flow rate
Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m
3

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/hr
3. ha = qa /A(Ts- Ta) W / m
2
K
qa = Rate of which air is getting heated.

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A = Test section area = ? x Di x L m
2

Ta = Average temperature of air = (T1 + T6)/2
o

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C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C
Cd = 0.64

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H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m

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3

d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

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using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di

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2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o

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C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings

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6. Prandtl Number:

27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k

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Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

k = Thermal conductivity of fluid W/m

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2
K
Nu = 0.023 (Re)
0.8
(Pr)

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0.4
Bulk mean temperature = (T1 + T6)/2

Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection

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apparatus.
hactual = -------------- W/m
2
K
htheoritical = -------------- W/m

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2
K

Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection

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apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is meant by boiling and condensation?

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2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?

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7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?

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12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:

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When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly

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temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The

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apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:

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1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:

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1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.

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5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)

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6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.

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Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities

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Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter
reading
(V)

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Ammeter
reading
(A)
T1
(

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0
C)
T2
(
0

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C)
T3
(
0
C)

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T4
(
0
C)
T5

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(
0
C)
T6
(

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0
C)
T7
(
0

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C)
T8
(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W

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b. Wood section = ---------------W
c. Asbestos section = ------------W

Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt

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and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.

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4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.

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8. Explain the significance of Fourier number.
9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

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DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

Aim:

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To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and

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T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

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Procedure:

1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.

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4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.


The readings are tabulated below

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Sl.No. Voltmeter
reading( V)
Ammeter
reading (A)

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T1
(
0
C)
T2

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(
0
C)
T3
(

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0
C)
T4
(
0

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C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm

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The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Fig. 1 Apparatus of thermal conductivity of insulating powder

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[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

Result:

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The thermal conductivity of insulating powder by conduction is found and the result is, ___________

Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is

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analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is the need for conducting this experiment?

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2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.

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7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?

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12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?

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17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.7

HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

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Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer
Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the

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fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:

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Sl.
No.
V I

Fin Temperatures (

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0
C)
Ambient Temp
(
0

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C)
Manometer
Reading
(V)

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(A)

T1 T2 T3 T4 T5 T6 T7 T8
h1
cm

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h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

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Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor

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9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C

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12. Temperature indicator = 0 ? 300
0
C
(With compensation of ambient temperature up-to 50
0

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C)
13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1

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T8
Brass Pin Fin
Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.

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3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.

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Procedure:
Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.

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3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)

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1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2

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) /4}?2gha m
3
/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m

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?w Density of water = 1000 kg/m
3

?a = Density of air = 1.165 kg/m
3

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g = acceleration due to gravity = 9.81 m/s
2

Cd = Coefficient of discharge = 0.64
D = diameter of the orifice

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3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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A = area of the duct
4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin

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v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2
o
C
5. Heat transfer coefficient, h = Nu k / D

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Where Nu = Nusselt Number
6. Nusselt Number:
Nu = CRe
m
(Pr)

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0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk

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m= ?(hp/kA)
A = area of fin = (? x D
2
) /4
L = Length of the fin

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Tw ? average temperature
T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were

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Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced

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convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.

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40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?

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5. Define ? Heat Transfer
6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?

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10. What is meant by steady state heat conduction?
11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number

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15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.8

DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

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Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer
(ii) Electric Heater

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(iii) Stop watch
(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.

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The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on

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the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm

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2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm

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7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C
= (or) 0.1 Kcal / kg

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0
C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

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11. Temperature indicator digital 0.1
0
C L.C 0 - 200

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0
C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water

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Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th

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4
? Td
4
)
Where, A = area of the disc

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Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

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Tabulations:
Proc

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edur
e:
1. H
eat the
water

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in the
tank by
the immersion heater up to a temperature of about 90
0
C.

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2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.

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5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

Result:

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The Stefan Boltzman constant was found out to be = _______________________ m/m
2
k
4
.

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Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,

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Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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Sl. No.
Hemisphere Temperature(
0
C) Avg. Temp.
of the

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Hemisphere
(Th)
T4
Steady
Temp. of

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Disc
T0 (Td)
Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number

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5. State Wien?s displacement law.
6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation

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10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?

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15. Explain the concept of black body.

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Viva ? voce
FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION

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MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex

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software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills

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4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning

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To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the

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career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society

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7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with

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coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:

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HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube

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5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface

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10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes

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13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.

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4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system

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13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES

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CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6

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2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3

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Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5

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Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7

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Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS

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11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68

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15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT

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USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate

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assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The

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heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:

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1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2

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Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently

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5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm

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2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm

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7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100
0

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C
9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm

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11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A

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16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C

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19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter
V
Ammeter

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A
Main heater (
0
C) Test Plate (
0

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C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.

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Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.

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4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.

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4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?

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9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?

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14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?

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19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF

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PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus

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Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter

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(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm

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5. The effective length of the above = 500 mm

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Precautions:

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1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W

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Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material

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k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.

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No.
Voltage
(V)
Current
(A)

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Heater Temperature
(
0
C)
Asbestos Temperature

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(
0
C)
Saw dust
Temperature (

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0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.

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2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.

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6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.

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The thermal conductivity of resistive material = _________________ W /m
2
-K

Outcome:

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From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:

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Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. Define ? Nusselt Number(Nu)

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2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)

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7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?

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12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?

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17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION

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FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The

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temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold

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fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Schematic view of the test set-up:
mm

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mm

19 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.

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5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A

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7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

Tabulation:

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Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m

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2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (

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0
C) ?
2. hL / k = A { g L
3
?T Cp ?/2v

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2
}
n

Where, hL / k are called Nusselt Number.

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L
3
g?T / v
2
is called Grashof number.

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?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid

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? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta

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For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)

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0.25
for 10
4
< Gr.Pr.<10
8

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hL / k = 0.13 (Gr.Pr)
1/3
for 10
8

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< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.

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4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as

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Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m
2

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K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC

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engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?

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6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?

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11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.

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16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to

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the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

Sl. No. Voltage Current Temperature in (
0

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C)
Manometer
reading of water
in h in meter

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(V) (A)
T1

T2

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T3

T4

T5

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T6

h1
cm

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h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer

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6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0
C
(Calibrated for chromel alumel thermocouple)

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8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.

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7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat

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input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)

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Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o
C)

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= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di

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2
?2gH x (?w / ?a) m
3
/hr
3. ha = qa /A(Ts- Ta) W / m

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2
K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

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Ta = Average temperature of air = (T1 + T6)/2
o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4

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o
C
Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m

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3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

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d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

using this procedure obtain the value of ?ha? for different air flow rate

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4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2
)/4]

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v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o
C
5. Nusselt Number:

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Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

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27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m

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2

k = Thermal conductivity of fluid W/m
2
K

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Nu = 0.023 (Re)
0.8
(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

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Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m

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2
K
htheoritical = -------------- W/m
2
K

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Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?

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4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?

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9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.

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14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

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29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

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Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the

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thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The

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temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is

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the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm

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3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat

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input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

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30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.

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7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow

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R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:

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Sl.No. Voltmeter
reading
(V)
Ammeter
reading

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(A)
T1
(
0
C)

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T2
(
0
C)
T3

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(
0
C)
T4
(

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0
C)
T5
(
0

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C)
T6
(
0
C)

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T7
(
0
C)
T8

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(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Composite wall apparatus set-up

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Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

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Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal

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conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?

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10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

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33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY

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OF INSULATING POWDER

Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

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The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit

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is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

Procedure:

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1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter

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reading( V)
Ammeter
reading (A)
T1
(

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0
C)
T2
(
0

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C)
T3
(
0
C)

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T4
(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1

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Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.


34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Fig. 1 Apparatus of thermal conductivity of insulating powder

[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater

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control]

Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

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Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to

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be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?

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4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?

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9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)

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14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?

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19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

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36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

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HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:

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A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is

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shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:
Sl.
No.

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V I

Fin Temperatures (
0
C)

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Ambient Temp
(
0
C)
Manometer

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Reading
(V)

(A)

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T1 T2 T3 T4 T5 T6 T7 T8
h1
cm
h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm

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3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.

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11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C
12. Temperature indicator = 0 ? 300
0

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C
(With compensation of ambient temperature up-to 50
0
C)
13. Dimmer stat for heat input controls 230 V, 2 A

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14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8
Brass Pin Fin

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Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

16. Ammeter = 0 ? 2 A

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.

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5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:
Forced Convection:

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1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient

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temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)

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Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m
3

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/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m
3

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?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s
2

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Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

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39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

A = area of the duct
4. Reynold?s Number:

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Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2

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o
C
5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number
6. Nusselt Number:

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Nu = CRe
m
(Pr)
0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)

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h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk
m= ?(hp/kA)
A = area of fin = (? x D

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2
) /4
L = Length of the fin
Tw ? average temperature
T? ? ambient (surface) temperature (T6)

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8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

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Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through

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pin-fin is to be found.


40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Extended Surface

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2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer
6. Define ? Fin Efficiency

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7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?
11. Define ? Convection

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12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

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41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.8

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DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus

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Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Geyser water

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Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to

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measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response

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of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm

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4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg

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0
C
= (or) 0.1 Kcal / kg
0
C

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9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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11. Temperature indicator digital 0.1
0
C L.C 0 - 200
0
C with built-in cold junction compensation and a timer set

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for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically

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there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4
? Td

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4
)
Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0

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dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:
Proc
edur
e:

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1. H
eat the
water
in the
tank by

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the immersion heater up to a temperature of about 90
0
C.
2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.

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4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate

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thermocouple).

Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m
2

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k
4
.

Outcome:

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From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.

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.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

Sl. No.
Hemisphere Temperature(

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0
C) Avg. Temp.
of the
Hemisphere
(Th)

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T4
Steady
Temp. of
Disc
T0 (Td)

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Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]

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2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number
5. State Wien?s displacement law.
6. What is the significance of Biot Number?

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7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation
10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]

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12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

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45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.9

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DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

Aim:
To measure emissivity of the test plate surface at various temperature

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:

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The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp

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black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.
Specifications:
1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W

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3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A

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7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300
0

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C.



FirstRanker.com - FirstRanker's Choice

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1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL

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2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels

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? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION

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MISSION
VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals

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2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which

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enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt

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and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able

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1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution

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5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both

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verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus

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3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)

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8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:

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11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus

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3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction

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7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-

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efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.

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15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.

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CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus

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11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15

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4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6

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Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43

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10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63

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14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75

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PROJECT WORK 81

8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:

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To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in

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which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.

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Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d

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2
(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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9 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.

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4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

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Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm

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5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0

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C ? 100
0
C
9. Maximum temperature of the hot plate = 170
0

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C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V

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14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200

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0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:
Sl. No. Voltmeter

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V
Ammeter
A
Main heater (
0

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C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.

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3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.

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7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be

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k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat

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exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity

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2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?

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7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.

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12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.

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17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

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Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus

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(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is

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transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside

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an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm

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3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.

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3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)

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Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found

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Tabulation:
Sl.
No.
Voltage
(V)

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Current
(A)
Heater Temperature
(
0

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C)
Asbestos Temperature
(
0
C)

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Saw dust
Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.

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5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.

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Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?

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5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?

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10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow

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15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.

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20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:

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To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of

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the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

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When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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Schematic view of the test set-up:
mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm

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4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel

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thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0

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c)

V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Heat transfer coefficient is given by

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h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m

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2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C

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q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L

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3
?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v

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2
is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface

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K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid

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G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K

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-1

Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been

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determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25
for 10
4

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< Gr.Pr.<10
8

hL / k = 0.13 (Gr.Pr)
1/3

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for 10
8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.

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2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

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Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K

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Experimental = ______________ W/ m
2
K

Outcomes:

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From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.

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4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.

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9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?

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14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness

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19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

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Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer

Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band

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heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to

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measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.


24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

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Sl. No. Voltage Current Temperature in (
0
C)
Manometer
reading of water

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in h in meter

(V) (A)
T1

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T2

T3

T4

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T5

T6

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h1
cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm

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4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0

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C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.

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5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference

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in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.

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4. Note down the heater input.

26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:

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1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (

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o
C)
= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr

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Q = Volume flow rate
Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m
3

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/hr
3. ha = qa /A(Ts- Ta) W / m
2
K
qa = Rate of which air is getting heated.

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A = Test section area = ? x Di x L m
2

Ta = Average temperature of air = (T1 + T6)/2
o

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C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C
Cd = 0.64

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H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m

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3

d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

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using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di

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2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o

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C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings

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6. Prandtl Number:

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Pr = Cp? / k

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Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

k = Thermal conductivity of fluid W/m

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2
K
Nu = 0.023 (Re)
0.8
(Pr)

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0.4
Bulk mean temperature = (T1 + T6)/2

Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection

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apparatus.
hactual = -------------- W/m
2
K
htheoritical = -------------- W/m

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2
K

Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection

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apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is meant by boiling and condensation?

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2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?

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7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?

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12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:

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When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly

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temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The

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apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:

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1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:

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1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.

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5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)

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6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.

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Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities

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Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter
reading
(V)

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Ammeter
reading
(A)
T1
(

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0
C)
T2
(
0

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C)
T3
(
0
C)

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T4
(
0
C)
T5

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(
0
C)
T6
(

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0
C)
T7
(
0

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C)
T8
(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W

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b. Wood section = ---------------W
c. Asbestos section = ------------W

Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt

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and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.

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4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.

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8. Explain the significance of Fourier number.
9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

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DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

Aim:

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To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and

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T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

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Procedure:

1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.

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4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.


The readings are tabulated below

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Sl.No. Voltmeter
reading( V)
Ammeter
reading (A)

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T1
(
0
C)
T2

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(
0
C)
T3
(

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0
C)
T4
(
0

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C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm

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The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Fig. 1 Apparatus of thermal conductivity of insulating powder

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[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

Result:

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The thermal conductivity of insulating powder by conduction is found and the result is, ___________

Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is

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analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is the need for conducting this experiment?

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2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.

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7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?

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12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?

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17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.7

HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

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Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer
Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the

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fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:

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Sl.
No.
V I

Fin Temperatures (

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0
C)
Ambient Temp
(
0

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C)
Manometer
Reading
(V)

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(A)

T1 T2 T3 T4 T5 T6 T7 T8
h1
cm

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h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

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Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor

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9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C

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12. Temperature indicator = 0 ? 300
0
C
(With compensation of ambient temperature up-to 50
0

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C)
13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1

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T8
Brass Pin Fin
Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.

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3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.

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Procedure:
Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.

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3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)

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1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2

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) /4}?2gha m
3
/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m

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?w Density of water = 1000 kg/m
3

?a = Density of air = 1.165 kg/m
3

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g = acceleration due to gravity = 9.81 m/s
2

Cd = Coefficient of discharge = 0.64
D = diameter of the orifice

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3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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A = area of the duct
4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin

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v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2
o
C
5. Heat transfer coefficient, h = Nu k / D

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Where Nu = Nusselt Number
6. Nusselt Number:
Nu = CRe
m
(Pr)

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0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk

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m= ?(hp/kA)
A = area of fin = (? x D
2
) /4
L = Length of the fin

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Tw ? average temperature
T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were

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Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced

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convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.

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40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?

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5. Define ? Heat Transfer
6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?

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10. What is meant by steady state heat conduction?
11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number

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15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.8

DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

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Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer
(ii) Electric Heater

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(iii) Stop watch
(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.

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The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on

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the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm

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2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm

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7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C
= (or) 0.1 Kcal / kg

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0
C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

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42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

11. Temperature indicator digital 0.1
0
C L.C 0 - 200

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0
C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water

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Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th

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4
? Td
4
)
Where, A = area of the disc

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Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

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43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulations:
Proc

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edur
e:
1. H
eat the
water

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in the
tank by
the immersion heater up to a temperature of about 90
0
C.

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2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.

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5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

Result:

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The Stefan Boltzman constant was found out to be = _______________________ m/m
2
k
4
.

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Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,

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Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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Sl. No.
Hemisphere Temperature(
0
C) Avg. Temp.
of the

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Hemisphere
(Th)
T4
Steady
Temp. of

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Disc
T0 (Td)
Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number

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5. State Wien?s displacement law.
6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation

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10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?

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15. Explain the concept of black body.

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Viva ? voce

45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.9

DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

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Aim:
To measure emissivity of the test plate surface at various temperature
Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer
Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats

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and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.
Specifications:

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1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each

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5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.

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10. Temperature Indicator = 0 ? 300
0
C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:

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1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.

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6. See that the black plate is having a layer of lamp black uniformly.
Tabulation:
Sl.
No
Voltage

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Current

Black body
temp(

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0
C)
Avg.
temp.

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Polished body
temp (
0
C)
Avg.

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temp.

Enclosure
Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,

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W1 ? W2 = (Eb ? E) ? (Ts
4
? Ta
4
) A

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Eb ? E = (W1 ? W2) / ? (Ts
4
? Ta
4
) A

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E = Eb ? {(W1 ? W2) / ? (Ts
4
? Ta
4
) A}

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Where,
W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd
2

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m
2

T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure

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Ts = surface temperature of the discs (or T1)
Eb = Emissivity of black plate = 1
E = Emissivity of Test plate
FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart

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and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION

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VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence

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To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design

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products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies

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5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering

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2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools

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6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms

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9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder

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4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant

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9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system

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12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection

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experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.

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12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC

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Boiler.



COURSE OBJECTIVES

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COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS

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1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11

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3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21

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5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31

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7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47

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CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14

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Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate

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method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters

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together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples

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No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2

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(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help

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of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:

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1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm

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6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100

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0
C
9. Maximum temperature of the hot plate = 170
0
C

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10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V

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15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0

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C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter
V

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Ammeter
A
Main heater (
0
C) Test Plate (

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0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:

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1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single

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phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.

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8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.

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3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?

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8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?

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13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?

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18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:

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To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple

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(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.

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There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.

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4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.

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4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging

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k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:

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Sl.
No.
Voltage
(V)
Current

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(A)
Heater Temperature
(
0
C)

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Asbestos Temperature
(
0
C)
Saw dust

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Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos

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layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:

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The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)

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6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?

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11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.

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16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical

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tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which

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in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.

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The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Schematic view of the test set-up:

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mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch

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Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples

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6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}

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Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W

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Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L
3

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?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v
2

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is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid

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v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity

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?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.

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hL / k = 0.56 (Gr.Pr)
0.25
for 10
4
< Gr.Pr.<10

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8

hL / k = 0.13 (Gr.Pr)
1/3
for 10

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8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).

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3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:

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The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m

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2
K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing

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heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?

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5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)

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10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness

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15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?

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20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:

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To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer

Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air

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stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of

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orifice meter and the water manometer fitted on the board.


24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

Sl. No. Voltage Current Temperature in (

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0
C)
Manometer
reading of water
in h in meter

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(V) (A)
T1

T2

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T3

T4

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T5

T6

h1

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cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor

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5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0
C

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(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:

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1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.

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6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.

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2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. The rate at which air is getting heated is calculated as

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qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o

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C)
= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate

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Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m
3
/hr

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3. ha = qa /A(Ts- Ta) W / m
2
K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m

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2

Ta = Average temperature of air = (T1 + T6)/2
o
C

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Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C
Cd = 0.64
H = Difference of water level in manometer m

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?w Density of water = 1000 Kg/m
3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

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d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

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using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2

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)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o
C

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5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

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27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k

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? = Viscosity Ns/m
2

k = Thermal conductivity of fluid W/m
2

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K
Nu = 0.023 (Re)
0.8
(Pr)
0.4

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Bulk mean temperature = (T1 + T6)/2

Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.

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hactual = -------------- W/m
2
K
htheoritical = -------------- W/m
2

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K

Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?

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3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?

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8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection

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13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

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Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,

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the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure

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temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat

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flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm

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2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.

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2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

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30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature

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gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:

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Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R

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Tabulation:
Sl.No. Voltmeter
reading
(V)
Ammeter

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reading
(A)
T1
(
0

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C)
T2
(
0
C)

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T3
(
0
C)
T4

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(
0
C)
T5
(

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0
C)
T6
(
0

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C)
T7
(
0
C)

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T8
(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Composite wall apparatus set-up

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Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W

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c. Asbestos section = ------------W

Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure

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Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?

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5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.

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9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

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33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

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DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

Aim:
To find out the thermal conductivity of insulating powder by conduction

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Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A

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multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

Procedure:

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1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.

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5. Repeat the experiments for different power inputs.


The readings are tabulated below

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Sl.No. Voltmeter
reading( V)
Ammeter
reading (A)
T1

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(
0
C)
T2
(

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0
C)
T3
(
0

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C)
T4
(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm

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The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Fig. 1 Apparatus of thermal conductivity of insulating powder

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[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

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Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam

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boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity

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3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.

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8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?

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13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?

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18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

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HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

Aim:

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To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is

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measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:
Sl.

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No.
V I

Fin Temperatures (
0

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C)
Ambient Temp
(
0
C)

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Manometer
Reading
(V)

(A)

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T1 T2 T3 T4 T5 T6 T7 T8
h1
cm
h2

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cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Duct size = 150 mm x 100 mm.

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2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

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Schematic view of the test set-up:



zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5

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10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C
12. Temperature indicator = 0 ? 300

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0
C
(With compensation of ambient temperature up-to 50
0
C)

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13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8

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Brass Pin Fin
Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.

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4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:

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Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.

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4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2

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Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m

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3
/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m

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3

?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s

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2

Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s

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Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

A = area of the duct

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4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.

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(T1 + T6) / 2
o
C
5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number

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6. Nusselt Number:
Nu = CRe
m
(Pr)
0.33

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7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk
m= ?(hp/kA)

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A = area of fin = (? x D
2
) /4
L = Length of the fin
Tw ? average temperature

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T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________

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Heat transfer, Q = ___________ W

Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.


40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer

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6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?

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11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.8

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DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

Aim:

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To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch

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(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water

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between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.

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When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere

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3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg

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8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C
= (or) 0.1 Kcal / kg
0

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C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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11. Temperature indicator digital 0.1
0
C L.C 0 - 200
0

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C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water
Precautions:

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Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4

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? Td
4
)
Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)

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Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

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43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulations:
Proc
edur

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e:
1. H
eat the
water
in the

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tank by
the immersion heater up to a temperature of about 90
0
C.
2. Remove the disc, D before pouring the hot water in the jacket.

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3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.

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6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m

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2
k
4
.

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Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using

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boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

Sl. No.

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Hemisphere Temperature(
0
C) Avg. Temp.
of the
Hemisphere

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(Th)
T4
Steady
Temp. of
Disc

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T0 (Td)
Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number
5. State Wien?s displacement law.

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6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation
10. What are the various modes of condensation?

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11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.9

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DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

Aim:

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To measure emissivity of the test plate surface at various temperature
Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The

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temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.
Specifications:
1. Heater input to black plate W1 = V1 x I1 W

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2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V

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6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300

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0
C.

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.

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Tabulation:
Sl.
No
Voltage

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Current

Black body
temp(
0

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C)
Avg.
temp.

Polished body

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temp (
0
C)
Avg.
temp.

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Enclosure
Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts

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4
? Ta
4
) A
Eb ? E = (W1 ? W2) / ? (Ts

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4
? Ta
4
) A
E = Eb ? {(W1 ? W2) / ? (Ts

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4
? Ta
4
) A}
Where,

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W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd
2
m

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2

T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)

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Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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? = Stefan boltzman constant = 5.67 x 10
-8
W/m
2
K

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4


Schematic view of the test set-up:

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Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by

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the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

Results:

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The emissivity of the test plate surface is found to be _____________.
Outcome:
From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

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FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________

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Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and

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enterprising professionals conforming to global standards through value based quality education and training.



? To provide competent technical manpower capable of meeting requirements of the industry

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? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING



Rendering the services to the global needs of engineering industries by educating students to become

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professionally sound mechanical engineers of excellent caliber



To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on

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experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould

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them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth

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To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up

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their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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PROGRAMME OUTCOMES (POs)

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On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications

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4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability

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8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills

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11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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ME6512 ? THERMAL ENGINEERING LABORATORY ? II



? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the

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performance of refrigeration cycle / components

LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus

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2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder

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7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

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REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System

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15. Performance test in a fluidized Bed Cooling Tower



1. Able to find out the thermal conductivity of various materials.

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2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials

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6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.

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11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures

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14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
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CONTENTS


Sl.No.
Name of the experiment

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Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe

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apparatus
11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder

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15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS

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6
Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39

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9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58

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13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS

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16 Air conditioning test rig 75
PROJECT WORK 81

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Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

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Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup

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(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to

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prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater

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assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved

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aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK

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3. Area, A = ( ?/4) d
2
(10 + x)

cm

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2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.

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2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there

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is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

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Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm

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4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40

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0
C ? 100
0
C
9. Maximum temperature of the hot plate = 170

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0
C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)

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13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)

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18. Temperature indicator = 0 ? 200
0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm

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21. Specimen used = Press wood

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Tabulation:

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Sl. No. Voltmeter
V
Ammeter
A
Main heater (

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0
C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water

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is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from

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thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably

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steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:

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Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded

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hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.

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6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer

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11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?

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16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

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Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup

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(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter
Theory:

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The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in

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the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:
1. Diameter of the heater Rod = 20 mm.

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2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).

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2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by

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Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging

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material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.
No.
Voltage

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(V)
Current
(A)
Heater Temperature
(

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0
C)
Asbestos Temperature
(
0

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C)
Saw dust
Temperature (
0
C)

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T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.

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4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.

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7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2

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-K

Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC

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engines, heat exchangers, etc. where heat transfer is to be found.

Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?

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4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?

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9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?

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14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis

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19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

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Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:
(i) Experimental setup

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(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at

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the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

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When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Schematic view of the test set-up:
mm
mm

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19 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm

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3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0

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C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V

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9. Heater = Cartridge type (400 W)

Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (

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0
c)

V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:

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1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2
K

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As = Area of heat transfer surface = ? x d x l m
2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0

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C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0
C) ?

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2. hL / k = A { g L
3
?T Cp ?/2v
2
}

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n

Where, hL / k are called Nusselt Number.
L
3

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g?T / v
2
is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.

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Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid

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? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0

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K
-1

Where Tf = (Ts + Ta )/ 2

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For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25
for 10

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4
< Gr.Pr.<10
8

hL / k = 0.13 (Gr.Pr)

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1/3
for 10
8
< Gr.Pr.<10
12

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Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

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Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2

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K
Experimental = ______________ W/ m
2
K

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Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?

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3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?

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8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer

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13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.

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18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No. 4

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

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Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:

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(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

Theory:

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Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat

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supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



Tabulations:

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Sl. No. Voltage Current Temperature in (
0
C)
Manometer

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reading of water
in h in meter

(V) (A)
T1

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T2

T3

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T4

T5

T6

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h1
cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm

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3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300

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0
C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A

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10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.

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4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:

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1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady

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state is reached.
4. Note down the heater input.

26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)

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?T = Temperature rise in air (
o
C)
= T6 ? T1.
2. m = Q?

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Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m

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3
/hr
3. ha = qa /A(Ts- Ta) W / m
2
K

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qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

Ta = Average temperature of air = (T1 + T6)/2

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o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C

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Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

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?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s

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2

using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number

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Where, V = velocity of air = Q/[(? x Di
2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2

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o
C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K

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Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

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k = Thermal conductivity of fluid W/m
2
K
Nu = 0.023 (Re)
0.8

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(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

Results:

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Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m
2
K

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htheoritical = -------------- W/m
2
K

Outcome:

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From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.

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6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?

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11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall

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Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The

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temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus

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uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.

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Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.

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Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.

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4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from

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the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate

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Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter
reading

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(V)
Ammeter
reading
(A)
T1

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(
0
C)
T2
(

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0
C)
T3
(
0

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C)
T4
(
0
C)

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T5
(
0
C)
T6

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(
0
C)
T7
(

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0
C)
T8
(
0

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C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:
The rate of heat transfer through different materials are found to be

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a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

Outcome:

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From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.



32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?

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3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.

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7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?

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12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

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Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between

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the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

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Procedure:

1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.

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3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter
reading( V)
Ammeter

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reading (A)
T1
(
0
C)

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T2
(
0
C)
T3

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(
0
C)
T4
(

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0
C)

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Calculations:

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The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Fig. 1 Apparatus of thermal conductivity of insulating powder

[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

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Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

Outcome:

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From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?

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6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?

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11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection

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16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.7

HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

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Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer
Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of

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the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:

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Forced convection:
Sl.
No.
V I

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Fin Temperatures (
0
C)
Ambient Temp
(

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0
C)
Manometer
Reading
(V)

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(A)

T1 T2 T3 T4 T5 T6 T7 T8
h1

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cm
h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm

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5. Diameter of the delivery pipe (O.D) = 46 mm

Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64

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8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0

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C
12. Temperature indicator = 0 ? 300
0
C
(With compensation of ambient temperature up-to 50

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0
C)
13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V

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T7 T6 T5 T4 T3 T2 T1
T8
Brass Pin Fin
Heater

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38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.

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7. Do not exceed 200 W.
Procedure:
Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.

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2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.

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Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D

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2
) /4}?2gha m
3
/s.
Where, ha (head of air) = (?w / ?a) x H m

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H = Difference of water level in manometer m
?w Density of water = 1000 kg/m
3

?a = Density of air = 1.165 kg/m

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3
g = acceleration due to gravity = 9.81 m/s
2

Cd = Coefficient of discharge = 0.64

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D = diameter of the orifice
3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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A = area of the duct
4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?

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D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2
o
C

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5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number
6. Nusselt Number:
Nu = CRe
m

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(Pr)
0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m

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k= 386 w/mk
m= ?(hp/kA)
A = area of fin = (? x D
2
) /4

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L = Length of the fin
Tw ? average temperature
T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:

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Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

Outcome:

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From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.

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40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.

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4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer
6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction

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9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?
11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?

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14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.8

DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

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Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer

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(ii) Electric Heater
(iii) Stop watch
(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The

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outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A

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chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:

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1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve

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6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C

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= (or) 0.1 Kcal / kg
0
C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

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42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

11. Temperature indicator digital 0.1
0

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C L.C 0 - 200
0
C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW

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13. Tank for hot water
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:

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Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4
? Td
4
)

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Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

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Schematic view of the test set-up:

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Heater

43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulations:

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Proc
edur
e:
1. H
eat the

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water
in the
tank by
the immersion heater up to a temperature of about 90
0

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C.
2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant

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cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

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Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m
2
k
4

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.

Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus

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is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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Sl. No.
Hemisphere Temperature(
0
C) Avg. Temp.

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of the
Hemisphere
(Th)
T4
Steady

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Temp. of
Disc
T0 (Td)
Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?
3. State Planck?s distribution law.

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4. Define ? Biot Number
5. State Wien?s displacement law.
6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.
8. What are the various types of convection?

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9. Define ? Condensation
10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?
13. State Krichoff's law or radiation

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14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.9

DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

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Aim:
To measure emissivity of the test plate surface at various temperature
Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer
Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide

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undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.

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Specifications:
1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.

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Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.

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9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300
0
C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.

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5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.
Tabulation:
Sl.
No

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Voltage

Current

Black body

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temp(
0
C)
Avg.
temp.

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Polished body
temp (
0
C)

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Avg.
temp.

Enclosure
Temp.

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(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:

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Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts
4
? Ta
4

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) A
Eb ? E = (W1 ? W2) / ? (Ts
4
? Ta
4

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) A
E = Eb ? {(W1 ? W2) / ? (Ts
4
? Ta
4

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) A}
Where,
W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd

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2
m
2

T = Temperature of black plate, k = (Ts + Ta) / 2

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Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)
Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

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47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

? = Stefan boltzman constant = 5.67 x 10
-8
W/m

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2
K
4

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Schematic view of the test set-up:


Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.

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And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by
the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

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Results:
The emissivity of the test plate surface is found to be _____________.
Outcome:
From this experiment, finding the emissivity of the test plate surface at various

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temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Emissivity

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2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?
4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?
6. What is meant by shape factor?

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7. Define ? Radiation
8. What is meant by monochromatic emissive power?
9. Define ? Emissive Power
10. What is meant by absorptivity?
11. Define ? Black Body

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12. What is meant by transmissivity?
13. State Plank's distribution law
14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce
FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?



DEPARTMENT OF

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MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

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Name : _______________________________________

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Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

--- Content provided by FirstRanker.com ---

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VISION
MISSION
VISION
MISSION

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4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals

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To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them

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3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills

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To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering

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and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME OUTCOMES (POs)

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On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship

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3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical

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environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination

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10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

--- Content provided by FirstRanker.com ---

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

--- Content provided by FirstRanker.com ---

? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:

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1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall

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6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

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REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor

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14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus

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5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.

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10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at

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various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
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CONTENTS


Sl.No.

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Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2

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Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3
Determination of heat transfer coefficient under natural convection from a

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vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27

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CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34

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8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51

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12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72

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ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

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Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:

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(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:

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The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.

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Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts

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on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:
1. Power input, Q = V ? A / 2 W

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2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:

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1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do

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not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm

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3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm

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8. Mean temperature range = 40
0
C ? 100
0
C

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9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)

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12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)

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17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C
19. Width of gap between two heater plates (x) = 2.5 mm

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20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter
V
Ammeter
A

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Main heater (
0
C) Test Plate (
0
C)

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T1 T2 T3 T4 T5 T6



Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.

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2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.

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5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

Outcome:

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From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

Applications:

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Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins

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5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?

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10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?

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15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?

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20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE

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APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:

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(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter

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Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:

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1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the

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experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:

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The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.

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L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.
No.

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Voltage
(V)
Current
(A)
Heater Temperature

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(
0
C)
Asbestos Temperature
(

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0
C)
Saw dust
Temperature (
0

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C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.

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3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by

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thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m

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2
-K

Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe

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apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:
Exhaust pipe lines, IC engines, heat exchangers

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?

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3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection

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8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?

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13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?

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18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

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Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:

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(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:

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The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is

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measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the

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relative motion of hot and cold fluid particles.

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Schematic view of the test set-up:
mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm

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2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300

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0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V

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8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

Tabulation:
Sl. No.

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Voltage Current Temperature of Thermocouple (
0
c)

V A

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T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2

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K
As = Area of heat transfer surface = ? x d x l m
2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7

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0
C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0

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C) ?
2. hL / k = A { g L
3
?T Cp ?/2v
2

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}
n

Where, hL / k are called Nusselt Number.
L

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3
g?T / v
2
is called Grashof number.
?Cp / k called Prandtl Number.

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A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid

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Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)

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0
K
-1

Where Tf = (Ts + Ta )/ 2

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For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25

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for 10
4
< Gr.Pr.<10
8

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hL / k = 0.13 (Gr.Pr)
1/3
for 10
8
< Gr.Pr.<10

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12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).

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5. Repeat the experiment at different heat inputs.

Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m

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2
K
Experimental = ______________ W/ m
2
K

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Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be

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found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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1. Define ? Grash of Number(Gr)

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2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness

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7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?

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12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.

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17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No. 4

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION

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FROM A TUBE

Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater

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is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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Tabulations:

Sl. No. Voltage Current Temperature in (
0
C)

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Manometer
reading of water
in h in meter

(V) (A)

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T1

T2

T3

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T4

T5

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T6

h1
cm
h2

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cm

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Specifications:
1. Pipe diameter outside (Do) = 40 mm

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2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C

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7. Temperature Indicator = Range 0 to 300
0
C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V

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9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.

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3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W

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Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.

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3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)

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Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o
C)
= T6 ? T1.

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2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di
2

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?2gH x (?w / ?a) m
3
/hr
3. ha = qa /A(Ts- Ta) W / m
2

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K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

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Ta = Average temperature of air = (T1 + T6)/2
o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o

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C
Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

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?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

d = diameter of orifice meter = 0.014 m

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g = acceleration due to gravity = 9.81 m/s
2

using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:

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Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature

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(T1 + T6)/2
o
C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number

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K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

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k = Thermal conductivity of fluid W/m
2
K
Nu = 0.023 (Re)

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0.8
(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

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Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m
2

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K
htheoritical = -------------- W/m
2
K

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Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.

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5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.

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10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?

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15. Define ? Momentum Thickness

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Viva ? voce

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29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:

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To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different

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materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A

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channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in

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series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm

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4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.

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3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as

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Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3

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Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter

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reading
(V)
Ammeter
reading
(A)

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T1
(
0
C)
T2

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(
0
C)
T3
(

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0
C)
T4
(
0

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C)
T5
(
0
C)

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T6
(
0
C)
T7

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(
0
C)
T8
(

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0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:

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The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

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Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. Define ? Heat Transfer

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2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?

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6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?
10. Define ? Heat Exchanger

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11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

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Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

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The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input

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power and dimmer stat is provided to vary the input power.

Procedure:

1. Switch on the unit and adjust the input power to the required extent.

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2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter
reading( V)

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Ammeter
reading (A)
T1
(
0

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C)
T2
(
0
C)

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T3
(
0
C)
T4

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(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the

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inner sphere, and the outer sphere respectively.


34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Fig. 1 Apparatus of thermal conductivity of insulating powder

[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

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Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

Outcome:

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From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?

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5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?

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10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)

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15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?

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20. What is meant by steady state heat conduction?

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Viva ? voce

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36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

HEAT TRANSFER FROM PIN-FIN APPARATUS

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(NATURAL AND FORCED CONVECTION MODES)

Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:

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(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is

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connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.

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Tabulations:
Forced convection:
Sl.
No.
V I

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Fin Temperatures (
0
C)
Ambient Temp

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(
0
C)
Manometer
Reading

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(V)

(A)

T1 T2 T3 T4 T5 T6 T7 T8

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h1
cm
h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm

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4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm

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7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.

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0
C
12. Temperature indicator = 0 ? 300
0
C

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(With compensation of ambient temperature up-to 50
0
C)
13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)

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15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8
Brass Pin Fin
Heater

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38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

16. Ammeter = 0 ? 2 A
Precautions:

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1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.

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6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:
Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,

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100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.

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5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)

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2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m
3
/s.

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Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m
3

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?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s
2

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Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

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39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

A = area of the duct
4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number

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Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2
o

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C
5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number
6. Nusselt Number:
Nu = CRe

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m
(Pr)
0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,

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Where, p = perimeter in m
k= 386 w/mk
m= ?(hp/kA)
A = area of fin = (? x D
2

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) /4
L = Length of the fin
Tw ? average temperature
T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL

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Results:
Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

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Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.

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40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Extended Surface
2. What is meant by convective mass transfer?

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3. State the applications of fins.
4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer
6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?

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8. Define ? Conduction
9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?
11. Define ? Convection
12. What is meant by transient heat conduction?

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13. What is meant by radiation?
14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

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41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.8

DETERMINATION OF STEFAN ? BOLTZMANN

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CONSTANT

Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:

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(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Geyser water
Theory:

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The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a

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hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.

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Specifications:
1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm

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5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0

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C
= (or) 0.1 Kcal / kg
0
C
9. No. of thermocouples mounted on B = 4 Nos.

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10. No. of thermocouples mounted on D = 1 No.

42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

11. Temperature indicator digital 0.1

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0
C L.C 0 - 200
0
C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.

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12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.

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Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4
? Td
4

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)
Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

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Schematic view of the test set-up:

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Heater

43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:
Proc
edur
e:
1. H

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eat the
water
in the
tank by
the immersion heater up to a temperature of about 90

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0
C.
2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling

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the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

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Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m
2
k

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4
.

Outcome:

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From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.
.Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

Sl. No.
Hemisphere Temperature(
0

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C) Avg. Temp.
of the
Hemisphere
(Th)
T4

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Steady
Temp. of
Disc
T0 (Td)
Time

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(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?

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3. State Planck?s distribution law.
4. Define ? Biot Number
5. State Wien?s displacement law.
6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.

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8. What are the various types of convection?
9. Define ? Condensation
10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?

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13. State Krichoff's law or radiation
14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

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45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.9

DETERMINATION OF EMISSIVITY OF A GREY

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SURFACE

Aim:
To measure emissivity of the test plate surface at various temperature
Apparatus required:

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(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with

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heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be

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determined.
Specifications:
1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)

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4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V

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8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300
0
C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.

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4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.
Tabulation:
Sl.

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No
Voltage

Current

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Black body
temp(
0
C)
Avg.

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temp.

Polished body
temp (
0

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C)
Avg.
temp.

Enclosure

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Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts
4
? Ta

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4
) A
Eb ? E = (W1 ? W2) / ? (Ts
4
? Ta

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4
) A
E = Eb ? {(W1 ? W2) / ? (Ts
4
? Ta

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4
) A}
Where,
W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W

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A = area of plates = 2 (?/4) xd
2
m
2

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T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)
Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

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47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

? = Stefan boltzman constant = 5.67 x 10
-8

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W/m
2
K
4

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Schematic view of the test set-up:


Procedure:

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1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by
the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state

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condition.

Results:
The emissivity of the test plate surface is found to be _____________.
Outcome:

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From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Emissivity
2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?
4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?

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6. What is meant by shape factor?
7. Define ? Radiation
8. What is meant by monochromatic emissive power?
9. Define ? Emissive Power
10. What is meant by absorptivity?

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11. Define ? Black Body
12. What is meant by transmissivity?
13. State Plank's distribution law
14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.10

EFFECTIVENESS OF PARALLEL / COUNTER
FLOW HEAT EXCHANGE

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Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:
(i) Experimental Setup
(ii) Stop watch

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(iii) Thermometer
Theory:
Heat exchangers are classified in three categories:
1. Transfer type
2. Storage type

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3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.
The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.

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ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water
which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by

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means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:
1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm

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3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50
0
C - 2 Nos.

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6. Thermometers (for hot water) = 0 ? 100
0
C - 2 Nos.
7. Measuring flask = 0 ? 1000 CC
FirstRanker.com - FirstRanker's Choice

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1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL

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2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels

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? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION

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MISSION
VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals

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2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which

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enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt

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and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able

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1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution

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5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both

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verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus

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3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)

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8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:

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11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus

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3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction

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7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-

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efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.

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15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.

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CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus

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11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15

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4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6

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Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43

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10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63

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14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75

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PROJECT WORK 81

8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:

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To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in

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which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.

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Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d

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2
(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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9 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.

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4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

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Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm

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5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0

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C ? 100
0
C
9. Maximum temperature of the hot plate = 170
0

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C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V

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14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200

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0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:
Sl. No. Voltmeter

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V
Ammeter
A
Main heater (
0

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C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.

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3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.

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7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be

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k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat

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exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity

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2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?

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7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.

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12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.

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17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

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Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus

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(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is

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transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside

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an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm

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3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.

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3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)

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Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found

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Tabulation:
Sl.
No.
Voltage
(V)

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Current
(A)
Heater Temperature
(
0

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C)
Asbestos Temperature
(
0
C)

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Saw dust
Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.

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5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.

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Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?

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5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?

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10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow

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15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.

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20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:

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To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of

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the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

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When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Schematic view of the test set-up:
mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm

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4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel

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thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0

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c)

V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Heat transfer coefficient is given by

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h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m

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2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C

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q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L

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3
?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v

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2
is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface

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K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid

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G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K

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-1

Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been

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determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25
for 10
4

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< Gr.Pr.<10
8

hL / k = 0.13 (Gr.Pr)
1/3

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for 10
8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.

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2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

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Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K

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Experimental = ______________ W/ m
2
K

Outcomes:

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From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.

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4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.

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9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?

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14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness

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19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

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Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer

Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band

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heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to

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measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.


24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

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Sl. No. Voltage Current Temperature in (
0
C)
Manometer
reading of water

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in h in meter

(V) (A)
T1

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T2

T3

T4

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T5

T6

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h1
cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm

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4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0

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C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.

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5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference

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in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.

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4. Note down the heater input.

26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:

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1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (

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o
C)
= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr

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Q = Volume flow rate
Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m
3

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/hr
3. ha = qa /A(Ts- Ta) W / m
2
K
qa = Rate of which air is getting heated.

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A = Test section area = ? x Di x L m
2

Ta = Average temperature of air = (T1 + T6)/2
o

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C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C
Cd = 0.64

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H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m

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3

d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

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using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di

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2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o

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C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings

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6. Prandtl Number:

27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k

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Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

k = Thermal conductivity of fluid W/m

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2
K
Nu = 0.023 (Re)
0.8
(Pr)

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0.4
Bulk mean temperature = (T1 + T6)/2

Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection

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apparatus.
hactual = -------------- W/m
2
K
htheoritical = -------------- W/m

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2
K

Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection

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apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is meant by boiling and condensation?

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2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?

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7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?

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12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:

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When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly

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temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The

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apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:

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1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:

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1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.

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5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)

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6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.

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Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities

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Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter
reading
(V)

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Ammeter
reading
(A)
T1
(

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0
C)
T2
(
0

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C)
T3
(
0
C)

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T4
(
0
C)
T5

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(
0
C)
T6
(

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0
C)
T7
(
0

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C)
T8
(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W

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b. Wood section = ---------------W
c. Asbestos section = ------------W

Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt

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and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.

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4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.

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8. Explain the significance of Fourier number.
9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

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DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

Aim:

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To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and

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T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

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Procedure:

1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.

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4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.


The readings are tabulated below

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Sl.No. Voltmeter
reading( V)
Ammeter
reading (A)

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T1
(
0
C)
T2

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(
0
C)
T3
(

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0
C)
T4
(
0

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C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm

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The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Fig. 1 Apparatus of thermal conductivity of insulating powder

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[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

Result:

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The thermal conductivity of insulating powder by conduction is found and the result is, ___________

Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is

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analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is the need for conducting this experiment?

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2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.

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7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?

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12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?

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17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.7

HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

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Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer
Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the

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fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:

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Sl.
No.
V I

Fin Temperatures (

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0
C)
Ambient Temp
(
0

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C)
Manometer
Reading
(V)

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(A)

T1 T2 T3 T4 T5 T6 T7 T8
h1
cm

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h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

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Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor

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9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C

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12. Temperature indicator = 0 ? 300
0
C
(With compensation of ambient temperature up-to 50
0

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C)
13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1

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T8
Brass Pin Fin
Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.

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3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.

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Procedure:
Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.

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3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)

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1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2

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) /4}?2gha m
3
/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m

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?w Density of water = 1000 kg/m
3

?a = Density of air = 1.165 kg/m
3

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g = acceleration due to gravity = 9.81 m/s
2

Cd = Coefficient of discharge = 0.64
D = diameter of the orifice

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3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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A = area of the duct
4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin

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v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2
o
C
5. Heat transfer coefficient, h = Nu k / D

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Where Nu = Nusselt Number
6. Nusselt Number:
Nu = CRe
m
(Pr)

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0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk

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m= ?(hp/kA)
A = area of fin = (? x D
2
) /4
L = Length of the fin

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Tw ? average temperature
T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were

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Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced

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convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.

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40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?

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5. Define ? Heat Transfer
6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?

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10. What is meant by steady state heat conduction?
11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number

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15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.8

DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

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Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer
(ii) Electric Heater

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(iii) Stop watch
(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.

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The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on

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the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm

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2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm

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7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C
= (or) 0.1 Kcal / kg

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0
C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

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42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

11. Temperature indicator digital 0.1
0
C L.C 0 - 200

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0
C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water

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Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th

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4
? Td
4
)
Where, A = area of the disc

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Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

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43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulations:
Proc

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edur
e:
1. H
eat the
water

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in the
tank by
the immersion heater up to a temperature of about 90
0
C.

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2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.

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5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

Result:

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The Stefan Boltzman constant was found out to be = _______________________ m/m
2
k
4
.

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Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,

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Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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Sl. No.
Hemisphere Temperature(
0
C) Avg. Temp.
of the

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Hemisphere
(Th)
T4
Steady
Temp. of

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Disc
T0 (Td)
Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number

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5. State Wien?s displacement law.
6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation

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10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?

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15. Explain the concept of black body.

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Viva ? voce

45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.9

DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

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Aim:
To measure emissivity of the test plate surface at various temperature
Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer
Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats

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and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.
Specifications:

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1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each

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5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.

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10. Temperature Indicator = 0 ? 300
0
C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:

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1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.

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6. See that the black plate is having a layer of lamp black uniformly.
Tabulation:
Sl.
No
Voltage

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Current

Black body
temp(

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0
C)
Avg.
temp.

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Polished body
temp (
0
C)
Avg.

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temp.

Enclosure
Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,

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W1 ? W2 = (Eb ? E) ? (Ts
4
? Ta
4
) A

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Eb ? E = (W1 ? W2) / ? (Ts
4
? Ta
4
) A

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E = Eb ? {(W1 ? W2) / ? (Ts
4
? Ta
4
) A}

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Where,
W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd
2

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m
2

T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure

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Ts = surface temperature of the discs (or T1)
Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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? = Stefan boltzman constant = 5.67 x 10
-8
W/m
2

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K
4


Schematic view of the test set-up:

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Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,

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2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by
the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

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Results:
The emissivity of the test plate surface is found to be _____________.
Outcome:
From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Emissivity
2. State Kirchoff?s law of radiation.

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3. What is meant by reflectivity?
4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?
6. What is meant by shape factor?
7. Define ? Radiation

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8. What is meant by monochromatic emissive power?
9. Define ? Emissive Power
10. What is meant by absorptivity?
11. Define ? Black Body
12. What is meant by transmissivity?

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13. State Plank's distribution law
14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

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49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.10

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EFFECTIVENESS OF PARALLEL / COUNTER
FLOW HEAT EXCHANGE

Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow

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Apparatus required:
(i) Experimental Setup
(ii) Stop watch
(iii) Thermometer
Theory:

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Heat exchangers are classified in three categories:
1. Transfer type
2. Storage type
3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is

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transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.
The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.

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The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water
which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.

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Specifications:
1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm

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5. Thermometers (for cold water) = 0 ? 50
0
C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100
0

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C - 2 Nos.
7. Measuring flask = 0 ? 1000 CC

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8. Geyser: single phase type to obtain hot water supply
9. Thermo Cole insulation for outer pipe.
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.

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Tabulations:
Sl.
No.
Flow Hot Fluid (
0

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C) Cold Fluid (
0
C)
Time for
collection of

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hot fluid
Kg/sec
Time for
collection
of cold fluid

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Kg/sec
1 Parallel flow
Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)
1. Area of the pipe A = ? (D ? d) L
Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube
L = Length of the tube

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2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W
FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION

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MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex

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software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills

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4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning

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To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the

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career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society

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7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with

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coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:

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HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube

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5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface

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10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes

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13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.

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4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system

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13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES

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CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6

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2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3

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Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5

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Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7

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Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS

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11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68

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15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT

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USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate

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assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The

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heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:

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1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2

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Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently

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5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm

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2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm

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7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100
0

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C
9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm

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11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A

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16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C

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19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter
V
Ammeter

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A
Main heater (
0
C) Test Plate (
0

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C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.

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Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.

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4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.

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4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?

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9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?

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14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?

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19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF

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PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus

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Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter

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(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm

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5. The effective length of the above = 500 mm

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Precautions:

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1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W

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Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material

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k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.

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No.
Voltage
(V)
Current
(A)

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Heater Temperature
(
0
C)
Asbestos Temperature

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(
0
C)
Saw dust
Temperature (

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0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.

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2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.

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6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.

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The thermal conductivity of resistive material = _________________ W /m
2
-K

Outcome:

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From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:

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Exhaust pipe lines, IC engines, heat exchangers

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1. Define ? Nusselt Number(Nu)

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2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)

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7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?

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12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?

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17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION

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FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The

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temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold

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fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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Schematic view of the test set-up:
mm

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mm

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Specifications:

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1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.

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5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A

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7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

Tabulation:

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Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m

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2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (

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0
C) ?
2. hL / k = A { g L
3
?T Cp ?/2v

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2
}
n

Where, hL / k are called Nusselt Number.

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L
3
g?T / v
2
is called Grashof number.

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?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid

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? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta

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For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)

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0.25
for 10
4
< Gr.Pr.<10
8

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hL / k = 0.13 (Gr.Pr)
1/3
for 10
8

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< Gr.Pr.<10
12
Here, L = Length of the cylinder

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.

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4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as

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Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m
2

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K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC

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engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?

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6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?

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11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.

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16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to

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the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

Sl. No. Voltage Current Temperature in (
0

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C)
Manometer
reading of water
in h in meter

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(V) (A)
T1

T2

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T3

T4

T5

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T6

h1
cm

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h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer

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6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0
C
(Calibrated for chromel alumel thermocouple)

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8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.

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7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat

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input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)

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Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o
C)

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= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di

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2
?2gH x (?w / ?a) m
3
/hr
3. ha = qa /A(Ts- Ta) W / m

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2
K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

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Ta = Average temperature of air = (T1 + T6)/2
o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4

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o
C
Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m

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3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

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d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

using this procedure obtain the value of ?ha? for different air flow rate

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4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2
)/4]

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v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o
C
5. Nusselt Number:

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Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

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27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m

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2

k = Thermal conductivity of fluid W/m
2
K

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Nu = 0.023 (Re)
0.8
(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

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Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m

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2
K
htheoritical = -------------- W/m
2
K

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Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?

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4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?

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9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.

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14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

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29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

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Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the

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thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The

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temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is

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the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm

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3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat

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input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

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30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.

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7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow

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R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:

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Sl.No. Voltmeter
reading
(V)
Ammeter
reading

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(A)
T1
(
0
C)

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T2
(
0
C)
T3

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(
0
C)
T4
(

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0
C)
T5
(
0

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C)
T6
(
0
C)

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T7
(
0
C)
T8

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(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Composite wall apparatus set-up

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Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

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Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal

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conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?

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10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

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33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY

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OF INSULATING POWDER

Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

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The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit

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is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

Procedure:

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1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter

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reading( V)
Ammeter
reading (A)
T1
(

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0
C)
T2
(
0

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C)
T3
(
0
C)

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T4
(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1

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Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.


34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Fig. 1 Apparatus of thermal conductivity of insulating powder

[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater

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control]

Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

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Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to

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be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?

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4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?

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9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)

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14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?

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19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

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36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

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HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:

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A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is

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shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:
Sl.
No.

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V I

Fin Temperatures (
0
C)

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Ambient Temp
(
0
C)
Manometer

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Reading
(V)

(A)

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T1 T2 T3 T4 T5 T6 T7 T8
h1
cm
h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm

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3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.

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11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C
12. Temperature indicator = 0 ? 300
0

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C
(With compensation of ambient temperature up-to 50
0
C)
13. Dimmer stat for heat input controls 230 V, 2 A

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14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8
Brass Pin Fin

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Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

16. Ammeter = 0 ? 2 A

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.

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5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:
Forced Convection:

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1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient

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temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)

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Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m
3

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/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m
3

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?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s
2

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Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

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39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

A = area of the duct
4. Reynold?s Number:

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Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2

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o
C
5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number
6. Nusselt Number:

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Nu = CRe
m
(Pr)
0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)

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h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk
m= ?(hp/kA)
A = area of fin = (? x D

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2
) /4
L = Length of the fin
Tw ? average temperature
T? ? ambient (surface) temperature (T6)

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8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

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Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through

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pin-fin is to be found.


40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Extended Surface

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2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer
6. Define ? Fin Efficiency

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7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?
11. Define ? Convection

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12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

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41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.8

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DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus

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Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Geyser water

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Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to

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measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response

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of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm

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4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg

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0
C
= (or) 0.1 Kcal / kg
0
C

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9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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11. Temperature indicator digital 0.1
0
C L.C 0 - 200
0
C with built-in cold junction compensation and a timer set

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for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically

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there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4
? Td

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4
)
Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0

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dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

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Tabulations:
Proc
edur
e:

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1. H
eat the
water
in the
tank by

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the immersion heater up to a temperature of about 90
0
C.
2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.

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4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate

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thermocouple).

Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m
2

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k
4
.

Outcome:

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From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.

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.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

Sl. No.
Hemisphere Temperature(

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0
C) Avg. Temp.
of the
Hemisphere
(Th)

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T4
Steady
Temp. of
Disc
T0 (Td)

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Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]

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2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number
5. State Wien?s displacement law.
6. What is the significance of Biot Number?

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7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation
10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]

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12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

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45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.9

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DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

Aim:
To measure emissivity of the test plate surface at various temperature

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:

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The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp

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black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.
Specifications:
1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W

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3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A

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7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300
0

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C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Use proper voltage range on Voltmeter.

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3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.
Tabulation:

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Sl.
No
Voltage

Current

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Black body
temp(
0
C)

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Avg.
temp.

Polished body
temp (

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0
C)
Avg.
temp.

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Enclosure
Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts
4

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? Ta
4
) A
Eb ? E = (W1 ? W2) / ? (Ts
4

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? Ta
4
) A
E = Eb ? {(W1 ? W2) / ? (Ts
4

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? Ta
4
) A}
Where,
W1 = Heater input to black plate = V1 x I1 W

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W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd
2
m
2

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T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)
Eb = Emissivity of black plate = 1

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E = Emissivity of Test plate

47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

? = Stefan boltzman constant = 5.67 x 10

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-8
W/m
2
K
4

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Schematic view of the test set-up:

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Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by
the dimmer stat so that the two plates will be maintained at the same temperature.

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3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

Results:
The emissivity of the test plate surface is found to be _____________.

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Outcome:
From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

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48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Emissivity
2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?
4. State Lambert?s cosine law.

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5. What is the purpose of radiation shield?
6. What is meant by shape factor?
7. Define ? Radiation
8. What is meant by monochromatic emissive power?
9. Define ? Emissive Power

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10. What is meant by absorptivity?
11. Define ? Black Body
12. What is meant by transmissivity?
13. State Plank's distribution law
14. What is meant by gray body?

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15. Define ? Irradiation

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Viva ? voce

49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.10

EFFECTIVENESS OF PARALLEL / COUNTER
FLOW HEAT EXCHANGE

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Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:
(i) Experimental Setup

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(ii) Stop watch
(iii) Thermometer
Theory:
Heat exchangers are classified in three categories:
1. Transfer type

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2. Storage type
3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.
The transfer type exchangers are further classified accordant to flow arrangements as:

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i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water
which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water

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flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:
1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm

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2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50
0

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C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100
0
C - 2 Nos.
7. Measuring flask = 0 ? 1000 CC

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50 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

8. Geyser: single phase type to obtain hot water supply
9. Thermo Cole insulation for outer pipe.

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Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Tabulations:
Sl.

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No.
Flow Hot Fluid (
0
C) Cold Fluid (
0

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C)
Time for
collection of
hot fluid
Kg/sec

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Time for
collection
of cold fluid
Kg/sec
1 Parallel flow

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Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)
1. Area of the pipe A = ? (D ? d) L

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Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube
L = Length of the tube

2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

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Where, m = mass flow rate Kg/ sec.
m = ?v/t, ? = density of water and t = time taken for hot water

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Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet
Tho = Temperature of hot water outlet

3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W

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Where, m = mass flow rate
Cp = Specific heat of capacity
Tco = Temperature of cold water inlet
Tci = Temperature of cold water outlet
4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W

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Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)
?Tm = (?Ti - ?To) / In (?Ti/?To)
Where, ?To = Tho ? Tco
?Ti = Thi ? Tci

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6. Over all heat transfer coefficient
h = Q?/?Tm A W/m
2
K
where Q? = (Qa + Qc) / 2

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Procedure:
1. Place the thermometers in position and note down their readings when they are at room temperature and
no water is flowing at either side. This is required to correct the temperature.
2. Start the flow on hot water side.

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3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.
5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.
6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.
7. Keeping the flow rates same, wait till the steady state conditions are reached.

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8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.
10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.
FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart

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and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION

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VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence

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To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design

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products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies

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5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering

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2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools

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6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms

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9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder

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4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant

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9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system

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12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection

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experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.

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12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC

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Boiler.



COURSE OBJECTIVES

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COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS

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1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11

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3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21

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5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31

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7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47

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CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14

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Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate

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method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters

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together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples

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No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2

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(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help

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of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:

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1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm

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6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100

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0
C
9. Maximum temperature of the hot plate = 170
0
C

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10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V

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15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0

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C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:
Sl. No. Voltmeter
V

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Ammeter
A
Main heater (
0
C) Test Plate (

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0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:

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1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single

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phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.

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8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.

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3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?

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8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?

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13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?

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18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:

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To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple

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(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.

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There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.

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4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.

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4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging

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k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:

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Sl.
No.
Voltage
(V)
Current

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(A)
Heater Temperature
(
0
C)

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Asbestos Temperature
(
0
C)
Saw dust

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Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos

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layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:

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The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)

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6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?

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11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.

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16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical

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tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which

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in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.

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The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Schematic view of the test set-up:

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mm
mm

19 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch

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Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples

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6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}

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Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W

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Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L
3

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?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v
2

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is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid

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v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity

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?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.

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hL / k = 0.56 (Gr.Pr)
0.25
for 10
4
< Gr.Pr.<10

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8

hL / k = 0.13 (Gr.Pr)
1/3
for 10

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8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).

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3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:

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The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m

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2
K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing

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heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?

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5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)

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10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness

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15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?

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20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:

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To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer

Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air

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stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of

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orifice meter and the water manometer fitted on the board.


24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

Sl. No. Voltage Current Temperature in (

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0
C)
Manometer
reading of water
in h in meter

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(V) (A)
T1

T2

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T3

T4

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T5

T6

h1

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cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor

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5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0
C

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(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:

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1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.

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6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.

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2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. The rate at which air is getting heated is calculated as

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qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o

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C)
= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate

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Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m
3
/hr

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3. ha = qa /A(Ts- Ta) W / m
2
K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m

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2

Ta = Average temperature of air = (T1 + T6)/2
o
C

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Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C
Cd = 0.64
H = Difference of water level in manometer m

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?w Density of water = 1000 Kg/m
3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

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d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

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using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2

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)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o
C

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5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

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27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k

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? = Viscosity Ns/m
2

k = Thermal conductivity of fluid W/m
2

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K
Nu = 0.023 (Re)
0.8
(Pr)
0.4

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Bulk mean temperature = (T1 + T6)/2

Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.

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hactual = -------------- W/m
2
K
htheoritical = -------------- W/m
2

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K

Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?

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3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?

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8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection

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13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

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Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,

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the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure

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temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat

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flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm

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2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.

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2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

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30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature

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gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:

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Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R

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Tabulation:
Sl.No. Voltmeter
reading
(V)
Ammeter

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reading
(A)
T1
(
0

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C)
T2
(
0
C)

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T3
(
0
C)
T4

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(
0
C)
T5
(

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0
C)
T6
(
0

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C)
T7
(
0
C)

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T8
(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Composite wall apparatus set-up

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Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W

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c. Asbestos section = ------------W

Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure

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Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?

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5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.

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9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

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33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

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DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

Aim:
To find out the thermal conductivity of insulating powder by conduction

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Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A

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multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

Procedure:

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1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.

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5. Repeat the experiments for different power inputs.


The readings are tabulated below

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Sl.No. Voltmeter
reading( V)
Ammeter
reading (A)
T1

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(
0
C)
T2
(

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0
C)
T3
(
0

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C)
T4
(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm

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The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Fig. 1 Apparatus of thermal conductivity of insulating powder

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[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

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Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam

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boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity

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3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.

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8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?

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13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?

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18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

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HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

Aim:

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To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is

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measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:
Sl.

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No.
V I

Fin Temperatures (
0

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C)
Ambient Temp
(
0
C)

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Manometer
Reading
(V)

(A)

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T1 T2 T3 T4 T5 T6 T7 T8
h1
cm
h2

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cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Duct size = 150 mm x 100 mm.

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2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

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Schematic view of the test set-up:



zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5

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10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C
12. Temperature indicator = 0 ? 300

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0
C
(With compensation of ambient temperature up-to 50
0
C)

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13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8

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Brass Pin Fin
Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.

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4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:

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Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.

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4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2

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Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m

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3
/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m

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3

?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s

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2

Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s

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Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

A = area of the duct

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4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.

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(T1 + T6) / 2
o
C
5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number

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6. Nusselt Number:
Nu = CRe
m
(Pr)
0.33

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7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk
m= ?(hp/kA)

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A = area of fin = (? x D
2
) /4
L = Length of the fin
Tw ? average temperature

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T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________

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Heat transfer, Q = ___________ W

Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.


40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer

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6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?

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11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.8

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DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

Aim:

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To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch

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(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water

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between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.

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When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere

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3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg

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8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C
= (or) 0.1 Kcal / kg
0

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C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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11. Temperature indicator digital 0.1
0
C L.C 0 - 200
0

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C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water
Precautions:

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Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4

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? Td
4
)
Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)

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Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

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43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulations:
Proc
edur

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e:
1. H
eat the
water
in the

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tank by
the immersion heater up to a temperature of about 90
0
C.
2. Remove the disc, D before pouring the hot water in the jacket.

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3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.

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6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m

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2
k
4
.

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Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using

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boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

Sl. No.

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Hemisphere Temperature(
0
C) Avg. Temp.
of the
Hemisphere

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(Th)
T4
Steady
Temp. of
Disc

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T0 (Td)
Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number
5. State Wien?s displacement law.

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6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation
10. What are the various modes of condensation?

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11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.9

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DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

Aim:

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To measure emissivity of the test plate surface at various temperature
Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The

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temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.
Specifications:
1. Heater input to black plate W1 = V1 x I1 W

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2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V

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6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300

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0
C.

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.

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Tabulation:
Sl.
No
Voltage

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Current

Black body
temp(
0

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C)
Avg.
temp.

Polished body

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temp (
0
C)
Avg.
temp.

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Enclosure
Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts

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4
? Ta
4
) A
Eb ? E = (W1 ? W2) / ? (Ts

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4
? Ta
4
) A
E = Eb ? {(W1 ? W2) / ? (Ts

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4
? Ta
4
) A}
Where,

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W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd
2
m

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2

T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)

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Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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? = Stefan boltzman constant = 5.67 x 10
-8
W/m
2
K

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4


Schematic view of the test set-up:

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Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by

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the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

Results:

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The emissivity of the test plate surface is found to be _____________.
Outcome:
From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

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48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Emissivity
2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?

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4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?
6. What is meant by shape factor?
7. Define ? Radiation
8. What is meant by monochromatic emissive power?

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9. Define ? Emissive Power
10. What is meant by absorptivity?
11. Define ? Black Body
12. What is meant by transmissivity?
13. State Plank's distribution law

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14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

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49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.10

EFFECTIVENESS OF PARALLEL / COUNTER

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FLOW HEAT EXCHANGE

Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:

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(i) Experimental Setup
(ii) Stop watch
(iii) Thermometer
Theory:
Heat exchangers are classified in three categories:

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1. Transfer type
2. Storage type
3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.

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The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water

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which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:

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1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50

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0
C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100
0
C - 2 Nos.

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7. Measuring flask = 0 ? 1000 CC

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8. Geyser: single phase type to obtain hot water supply

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9. Thermo Cole insulation for outer pipe.
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Tabulations:

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Sl.
No.
Flow Hot Fluid (
0
C) Cold Fluid (

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0
C)
Time for
collection of
hot fluid

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Kg/sec
Time for
collection
of cold fluid
Kg/sec

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1 Parallel flow
Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)

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1. Area of the pipe A = ? (D ? d) L
Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube
L = Length of the tube

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2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

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Where, m = mass flow rate Kg/ sec.

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m = ?v/t, ? = density of water and t = time taken for hot water
Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet
Tho = Temperature of hot water outlet

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3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W
Where, m = mass flow rate
Cp = Specific heat of capacity
Tco = Temperature of cold water inlet
Tci = Temperature of cold water outlet

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4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W
Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)
?Tm = (?Ti - ?To) / In (?Ti/?To)
Where, ?To = Tho ? Tco

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?Ti = Thi ? Tci
6. Over all heat transfer coefficient
h = Q?/?Tm A W/m
2
K

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where Q? = (Qa + Qc) / 2

Procedure:
1. Place the thermometers in position and note down their readings when they are at room temperature and
no water is flowing at either side. This is required to correct the temperature.

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2. Start the flow on hot water side.
3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.
5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.
6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.

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7. Keeping the flow rates same, wait till the steady state conditions are reached.
8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.
10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

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52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Result:
1. The values of effectiveness of heat exchanger were found as

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(i) Parallel flow = ________.
(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)
(i) Parallel flow = ________.
(ii) Counter flow = _________.

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Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow
heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat
exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Heat Exchanger
2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?
4. Write about the merits of drop wise condensation.
5. What is meant by film wise and drop wise condensation?

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6. What is meant by effectiveness?
7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?
9. Distinguish between regenerator and recuperates.
10. What is meant by parallel flow heat exchanger?

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11. What is meant by counter flow heat exchanger?
12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?
Viva ? voce
FirstRanker.com - FirstRanker's Choice

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1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL

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2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels

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? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION

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MISSION
VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals

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2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which

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enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt

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and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able

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1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution

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5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both

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verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus

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3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)

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8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:

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11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus

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3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction

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7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-

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efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.

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15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.

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CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus

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11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15

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4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6

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Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43

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10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63

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14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75

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PROJECT WORK 81

8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:

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To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in

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which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.

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Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d

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2
(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.

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4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

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Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm

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5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0

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C ? 100
0
C
9. Maximum temperature of the hot plate = 170
0

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C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V

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14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200

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0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:
Sl. No. Voltmeter

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V
Ammeter
A
Main heater (
0

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C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.

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3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.

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7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be

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k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat

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exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity

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2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?

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7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.

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12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.

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17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

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Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus

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(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is

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transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside

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an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm

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3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.

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3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)

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Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found

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Tabulation:
Sl.
No.
Voltage
(V)

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Current
(A)
Heater Temperature
(
0

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C)
Asbestos Temperature
(
0
C)

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Saw dust
Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.

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5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.

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Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?

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5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?

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10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow

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15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.

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20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:

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To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of

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the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

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When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Schematic view of the test set-up:
mm
mm

19 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm

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4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel

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thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0

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c)

V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Heat transfer coefficient is given by

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h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m

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2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C

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q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L

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3
?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v

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2
is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface

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K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid

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G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K

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-1

Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been

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determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25
for 10
4

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< Gr.Pr.<10
8

hL / k = 0.13 (Gr.Pr)
1/3

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for 10
8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.

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2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

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Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K

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Experimental = ______________ W/ m
2
K

Outcomes:

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From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.

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4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.

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9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?

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14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness

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19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

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Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer

Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band

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heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to

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measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.


24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

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Sl. No. Voltage Current Temperature in (
0
C)
Manometer
reading of water

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in h in meter

(V) (A)
T1

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T2

T3

T4

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T5

T6

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h1
cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm

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4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0

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C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.

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5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference

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in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.

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4. Note down the heater input.

26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:

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1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (

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o
C)
= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr

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Q = Volume flow rate
Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m
3

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/hr
3. ha = qa /A(Ts- Ta) W / m
2
K
qa = Rate of which air is getting heated.

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A = Test section area = ? x Di x L m
2

Ta = Average temperature of air = (T1 + T6)/2
o

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C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C
Cd = 0.64

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H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m

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3

d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

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using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di

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2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o

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C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings

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6. Prandtl Number:

27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k

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Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

k = Thermal conductivity of fluid W/m

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2
K
Nu = 0.023 (Re)
0.8
(Pr)

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0.4
Bulk mean temperature = (T1 + T6)/2

Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection

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apparatus.
hactual = -------------- W/m
2
K
htheoritical = -------------- W/m

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2
K

Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection

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apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is meant by boiling and condensation?

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2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?

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7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?

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12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:

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When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly

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temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The

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apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:

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1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:

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1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.

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5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)

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6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.

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Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities

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Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter
reading
(V)

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Ammeter
reading
(A)
T1
(

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0
C)
T2
(
0

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C)
T3
(
0
C)

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T4
(
0
C)
T5

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(
0
C)
T6
(

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0
C)
T7
(
0

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C)
T8
(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W

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b. Wood section = ---------------W
c. Asbestos section = ------------W

Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt

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and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.

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4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.

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8. Explain the significance of Fourier number.
9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

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DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

Aim:

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To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and

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T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

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Procedure:

1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.

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4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.


The readings are tabulated below

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Sl.No. Voltmeter
reading( V)
Ammeter
reading (A)

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T1
(
0
C)
T2

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(
0
C)
T3
(

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0
C)
T4
(
0

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C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm

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The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Fig. 1 Apparatus of thermal conductivity of insulating powder

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[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

Result:

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The thermal conductivity of insulating powder by conduction is found and the result is, ___________

Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is

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analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is the need for conducting this experiment?

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2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.

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7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?

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12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?

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17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.7

HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

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Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer
Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the

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fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:

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Sl.
No.
V I

Fin Temperatures (

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0
C)
Ambient Temp
(
0

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C)
Manometer
Reading
(V)

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(A)

T1 T2 T3 T4 T5 T6 T7 T8
h1
cm

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h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

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Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor

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9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C

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12. Temperature indicator = 0 ? 300
0
C
(With compensation of ambient temperature up-to 50
0

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C)
13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1

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T8
Brass Pin Fin
Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.

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3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.

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Procedure:
Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.

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3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)

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1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2

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) /4}?2gha m
3
/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m

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?w Density of water = 1000 kg/m
3

?a = Density of air = 1.165 kg/m
3

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g = acceleration due to gravity = 9.81 m/s
2

Cd = Coefficient of discharge = 0.64
D = diameter of the orifice

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3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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A = area of the duct
4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin

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v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2
o
C
5. Heat transfer coefficient, h = Nu k / D

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Where Nu = Nusselt Number
6. Nusselt Number:
Nu = CRe
m
(Pr)

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0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk

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m= ?(hp/kA)
A = area of fin = (? x D
2
) /4
L = Length of the fin

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Tw ? average temperature
T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were

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Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced

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convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.

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40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?

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5. Define ? Heat Transfer
6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?

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10. What is meant by steady state heat conduction?
11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number

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15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.8

DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

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Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer
(ii) Electric Heater

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(iii) Stop watch
(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.

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The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on

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the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm

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2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm

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7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C
= (or) 0.1 Kcal / kg

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0
C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

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42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

11. Temperature indicator digital 0.1
0
C L.C 0 - 200

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0
C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water

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Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th

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4
? Td
4
)
Where, A = area of the disc

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Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

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43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulations:
Proc

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edur
e:
1. H
eat the
water

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in the
tank by
the immersion heater up to a temperature of about 90
0
C.

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2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.

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5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

Result:

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The Stefan Boltzman constant was found out to be = _______________________ m/m
2
k
4
.

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Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,

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Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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Sl. No.
Hemisphere Temperature(
0
C) Avg. Temp.
of the

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Hemisphere
(Th)
T4
Steady
Temp. of

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Disc
T0 (Td)
Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number

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5. State Wien?s displacement law.
6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation

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10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?

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15. Explain the concept of black body.

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Viva ? voce

45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.9

DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

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Aim:
To measure emissivity of the test plate surface at various temperature
Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer
Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats

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and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.
Specifications:

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1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each

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5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.

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10. Temperature Indicator = 0 ? 300
0
C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:

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1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.

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6. See that the black plate is having a layer of lamp black uniformly.
Tabulation:
Sl.
No
Voltage

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Current

Black body
temp(

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0
C)
Avg.
temp.

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Polished body
temp (
0
C)
Avg.

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temp.

Enclosure
Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,

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W1 ? W2 = (Eb ? E) ? (Ts
4
? Ta
4
) A

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Eb ? E = (W1 ? W2) / ? (Ts
4
? Ta
4
) A

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E = Eb ? {(W1 ? W2) / ? (Ts
4
? Ta
4
) A}

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Where,
W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd
2

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m
2

T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure

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Ts = surface temperature of the discs (or T1)
Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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? = Stefan boltzman constant = 5.67 x 10
-8
W/m
2

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K
4


Schematic view of the test set-up:

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Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,

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2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by
the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

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Results:
The emissivity of the test plate surface is found to be _____________.
Outcome:
From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Emissivity
2. State Kirchoff?s law of radiation.

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3. What is meant by reflectivity?
4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?
6. What is meant by shape factor?
7. Define ? Radiation

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8. What is meant by monochromatic emissive power?
9. Define ? Emissive Power
10. What is meant by absorptivity?
11. Define ? Black Body
12. What is meant by transmissivity?

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13. State Plank's distribution law
14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

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49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.10

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EFFECTIVENESS OF PARALLEL / COUNTER
FLOW HEAT EXCHANGE

Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow

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Apparatus required:
(i) Experimental Setup
(ii) Stop watch
(iii) Thermometer
Theory:

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Heat exchangers are classified in three categories:
1. Transfer type
2. Storage type
3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is

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transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.
The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.

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The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water
which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.

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Specifications:
1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm

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5. Thermometers (for cold water) = 0 ? 50
0
C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100
0

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C - 2 Nos.
7. Measuring flask = 0 ? 1000 CC

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8. Geyser: single phase type to obtain hot water supply
9. Thermo Cole insulation for outer pipe.
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.

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Tabulations:
Sl.
No.
Flow Hot Fluid (
0

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C) Cold Fluid (
0
C)
Time for
collection of

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hot fluid
Kg/sec
Time for
collection
of cold fluid

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Kg/sec
1 Parallel flow
Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)
1. Area of the pipe A = ? (D ? d) L
Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube
L = Length of the tube

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2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

51 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Where, m = mass flow rate Kg/ sec.
m = ?v/t, ? = density of water and t = time taken for hot water
Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet
Tho = Temperature of hot water outlet

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3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W
Where, m = mass flow rate
Cp = Specific heat of capacity
Tco = Temperature of cold water inlet

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Tci = Temperature of cold water outlet
4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W
Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)
?Tm = (?Ti - ?To) / In (?Ti/?To)

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Where, ?To = Tho ? Tco
?Ti = Thi ? Tci
6. Over all heat transfer coefficient
h = Q?/?Tm A W/m
2

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K
where Q? = (Qa + Qc) / 2

Procedure:
1. Place the thermometers in position and note down their readings when they are at room temperature and

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no water is flowing at either side. This is required to correct the temperature.
2. Start the flow on hot water side.
3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.
5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.

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6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.
7. Keeping the flow rates same, wait till the steady state conditions are reached.
8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.
10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

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52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Result:

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1. The values of effectiveness of heat exchanger were found as
(i) Parallel flow = ________.
(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)
(i) Parallel flow = ________.

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(ii) Counter flow = _________.

Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow
heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat

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exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Heat Exchanger
2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?
4. Write about the merits of drop wise condensation.

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5. What is meant by film wise and drop wise condensation?
6. What is meant by effectiveness?
7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?
9. Distinguish between regenerator and recuperates.

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10. What is meant by parallel flow heat exchanger?
11. What is meant by counter flow heat exchanger?
12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?
Viva ? voce

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53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.11

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DETERMINATION OF COP OF A REFRIGERATION
SYSTEM

Aim:
To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration

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system
Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch

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(iv) Experimental setup
Description:
1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a
reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.
2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated

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wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a
low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the
temperature of chilled water. The above unit is located on the trolley behind front panel.
3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic
expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum

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strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure
gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high
pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy
meter to measure the power consumed either by hater or by compressor.

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FirstRanker.com - FirstRanker's Choice

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1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL

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2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels

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? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION

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MISSION
VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals

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2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which

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enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt

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and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able

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1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution

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5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both

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verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus

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3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)

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8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:

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11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus

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3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction

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7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-

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efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.

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15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
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CONTENTS

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Sl.No.
Name of the experiment
Page No.

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CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus

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11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15

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4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6

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Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43

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10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63

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14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75

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PROJECT WORK 81

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Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:

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To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in

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which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.

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Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d

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2
(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.

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4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

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Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm

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5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0

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C ? 100
0
C
9. Maximum temperature of the hot plate = 170
0

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C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V

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14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200

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0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter

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V
Ammeter
A
Main heater (
0

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C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.

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3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.

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7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be

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k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat

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exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity

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2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?

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7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.

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12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.

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17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

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Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus

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(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is

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transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside

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an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm

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3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.

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3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)

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Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found

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Tabulation:
Sl.
No.
Voltage
(V)

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Current
(A)
Heater Temperature
(
0

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C)
Asbestos Temperature
(
0
C)

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Saw dust
Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.

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5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.

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Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?

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5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?

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10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow

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15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.

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20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:

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To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of

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the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

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When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Schematic view of the test set-up:
mm
mm

19 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm

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4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel

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thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0

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c)

V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Heat transfer coefficient is given by

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h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m

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2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C

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q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L

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3
?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v

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2
is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface

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K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid

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G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K

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-1

Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been

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determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25
for 10
4

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< Gr.Pr.<10
8

hL / k = 0.13 (Gr.Pr)
1/3

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for 10
8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.

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2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

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Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K

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Experimental = ______________ W/ m
2
K

Outcomes:

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From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.

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4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.

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9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?

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14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness

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19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

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Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer

Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band

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heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to

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measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.


24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

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Sl. No. Voltage Current Temperature in (
0
C)
Manometer
reading of water

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in h in meter

(V) (A)
T1

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T2

T3

T4

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T5

T6

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h1
cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm

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4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0

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C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.

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5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference

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in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.

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4. Note down the heater input.

26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:

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1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (

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o
C)
= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr

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Q = Volume flow rate
Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m
3

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/hr
3. ha = qa /A(Ts- Ta) W / m
2
K
qa = Rate of which air is getting heated.

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A = Test section area = ? x Di x L m
2

Ta = Average temperature of air = (T1 + T6)/2
o

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C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C
Cd = 0.64

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H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m

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3

d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

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using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di

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2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o

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C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings

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6. Prandtl Number:

27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k

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Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

k = Thermal conductivity of fluid W/m

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2
K
Nu = 0.023 (Re)
0.8
(Pr)

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0.4
Bulk mean temperature = (T1 + T6)/2

Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection

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apparatus.
hactual = -------------- W/m
2
K
htheoritical = -------------- W/m

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2
K

Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection

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apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is meant by boiling and condensation?

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2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?

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7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?

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12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:

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When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly

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temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The

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apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:

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1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:

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1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.

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5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)

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6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.

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Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities

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Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter
reading
(V)

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Ammeter
reading
(A)
T1
(

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0
C)
T2
(
0

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C)
T3
(
0
C)

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T4
(
0
C)
T5

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(
0
C)
T6
(

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0
C)
T7
(
0

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C)
T8
(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W

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b. Wood section = ---------------W
c. Asbestos section = ------------W

Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt

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and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.

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4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.

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8. Explain the significance of Fourier number.
9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

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DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

Aim:

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To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and

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T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

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Procedure:

1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.

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4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.


The readings are tabulated below

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Sl.No. Voltmeter
reading( V)
Ammeter
reading (A)

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T1
(
0
C)
T2

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(
0
C)
T3
(

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0
C)
T4
(
0

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C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm

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The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Fig. 1 Apparatus of thermal conductivity of insulating powder

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[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

Result:

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The thermal conductivity of insulating powder by conduction is found and the result is, ___________

Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is

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analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is the need for conducting this experiment?

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2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.

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7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?

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12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?

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17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.7

HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

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Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer
Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the

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fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:

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Sl.
No.
V I

Fin Temperatures (

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0
C)
Ambient Temp
(
0

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C)
Manometer
Reading
(V)

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(A)

T1 T2 T3 T4 T5 T6 T7 T8
h1
cm

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h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

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Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor

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9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C

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12. Temperature indicator = 0 ? 300
0
C
(With compensation of ambient temperature up-to 50
0

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C)
13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1

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T8
Brass Pin Fin
Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.

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3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.

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Procedure:
Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.

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3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)

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1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2

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) /4}?2gha m
3
/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m

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?w Density of water = 1000 kg/m
3

?a = Density of air = 1.165 kg/m
3

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g = acceleration due to gravity = 9.81 m/s
2

Cd = Coefficient of discharge = 0.64
D = diameter of the orifice

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3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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A = area of the duct
4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin

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v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2
o
C
5. Heat transfer coefficient, h = Nu k / D

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Where Nu = Nusselt Number
6. Nusselt Number:
Nu = CRe
m
(Pr)

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0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk

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m= ?(hp/kA)
A = area of fin = (? x D
2
) /4
L = Length of the fin

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Tw ? average temperature
T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were

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Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced

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convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.

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40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?

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5. Define ? Heat Transfer
6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?

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10. What is meant by steady state heat conduction?
11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number

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15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.8

DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

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Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer
(ii) Electric Heater

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(iii) Stop watch
(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.

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The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on

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the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm

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2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm

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7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C
= (or) 0.1 Kcal / kg

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0
C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

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42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

11. Temperature indicator digital 0.1
0
C L.C 0 - 200

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0
C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water

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Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th

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4
? Td
4
)
Where, A = area of the disc

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Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

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43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulations:
Proc

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edur
e:
1. H
eat the
water

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in the
tank by
the immersion heater up to a temperature of about 90
0
C.

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2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.

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5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

Result:

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The Stefan Boltzman constant was found out to be = _______________________ m/m
2
k
4
.

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Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,

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Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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Sl. No.
Hemisphere Temperature(
0
C) Avg. Temp.
of the

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Hemisphere
(Th)
T4
Steady
Temp. of

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Disc
T0 (Td)
Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number

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5. State Wien?s displacement law.
6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation

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10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?

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15. Explain the concept of black body.

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Viva ? voce

45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.9

DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

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Aim:
To measure emissivity of the test plate surface at various temperature
Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer
Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats

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and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.
Specifications:

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1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each

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5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.

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10. Temperature Indicator = 0 ? 300
0
C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:

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1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.

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6. See that the black plate is having a layer of lamp black uniformly.
Tabulation:
Sl.
No
Voltage

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Current

Black body
temp(

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0
C)
Avg.
temp.

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Polished body
temp (
0
C)
Avg.

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temp.

Enclosure
Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,

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W1 ? W2 = (Eb ? E) ? (Ts
4
? Ta
4
) A

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Eb ? E = (W1 ? W2) / ? (Ts
4
? Ta
4
) A

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E = Eb ? {(W1 ? W2) / ? (Ts
4
? Ta
4
) A}

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Where,
W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd
2

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m
2

T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure

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Ts = surface temperature of the discs (or T1)
Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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? = Stefan boltzman constant = 5.67 x 10
-8
W/m
2

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K
4


Schematic view of the test set-up:

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Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,

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2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by
the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

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Results:
The emissivity of the test plate surface is found to be _____________.
Outcome:
From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Emissivity
2. State Kirchoff?s law of radiation.

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3. What is meant by reflectivity?
4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?
6. What is meant by shape factor?
7. Define ? Radiation

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8. What is meant by monochromatic emissive power?
9. Define ? Emissive Power
10. What is meant by absorptivity?
11. Define ? Black Body
12. What is meant by transmissivity?

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13. State Plank's distribution law
14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

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49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.10

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EFFECTIVENESS OF PARALLEL / COUNTER
FLOW HEAT EXCHANGE

Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow

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Apparatus required:
(i) Experimental Setup
(ii) Stop watch
(iii) Thermometer
Theory:

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Heat exchangers are classified in three categories:
1. Transfer type
2. Storage type
3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is

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transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.
The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.

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The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water
which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.

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Specifications:
1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm

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5. Thermometers (for cold water) = 0 ? 50
0
C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100
0

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C - 2 Nos.
7. Measuring flask = 0 ? 1000 CC

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8. Geyser: single phase type to obtain hot water supply
9. Thermo Cole insulation for outer pipe.
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.

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Tabulations:
Sl.
No.
Flow Hot Fluid (
0

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C) Cold Fluid (
0
C)
Time for
collection of

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hot fluid
Kg/sec
Time for
collection
of cold fluid

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Kg/sec
1 Parallel flow
Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)
1. Area of the pipe A = ? (D ? d) L
Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube
L = Length of the tube

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2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

51 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Where, m = mass flow rate Kg/ sec.
m = ?v/t, ? = density of water and t = time taken for hot water
Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet
Tho = Temperature of hot water outlet

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3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W
Where, m = mass flow rate
Cp = Specific heat of capacity
Tco = Temperature of cold water inlet

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Tci = Temperature of cold water outlet
4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W
Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)
?Tm = (?Ti - ?To) / In (?Ti/?To)

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Where, ?To = Tho ? Tco
?Ti = Thi ? Tci
6. Over all heat transfer coefficient
h = Q?/?Tm A W/m
2

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K
where Q? = (Qa + Qc) / 2

Procedure:
1. Place the thermometers in position and note down their readings when they are at room temperature and

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no water is flowing at either side. This is required to correct the temperature.
2. Start the flow on hot water side.
3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.
5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.

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6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.
7. Keeping the flow rates same, wait till the steady state conditions are reached.
8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.
10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

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52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Result:

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1. The values of effectiveness of heat exchanger were found as
(i) Parallel flow = ________.
(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)
(i) Parallel flow = ________.

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(ii) Counter flow = _________.

Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow
heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat

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exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Heat Exchanger
2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?
4. Write about the merits of drop wise condensation.

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5. What is meant by film wise and drop wise condensation?
6. What is meant by effectiveness?
7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?
9. Distinguish between regenerator and recuperates.

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10. What is meant by parallel flow heat exchanger?
11. What is meant by counter flow heat exchanger?
12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?
Viva ? voce

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53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.11

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DETERMINATION OF COP OF A REFRIGERATION
SYSTEM

Aim:
To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration

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system
Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch

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(iv) Experimental setup
Description:
1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a
reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.
2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated

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wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a
low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the
temperature of chilled water. The above unit is located on the trolley behind front panel.
3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic
expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum

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strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure
gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high
pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy
meter to measure the power consumed either by hater or by compressor.

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54 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
A. A compressor condenser unit placed inside trolley and fitted with
1. R-134a reciprocating compressor

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2. Condenser
3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan
4. A receiver with angle check valve
B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity
placed inside a well insulated wooden box and provided with

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5. Evaporator coil
6. Stirrer
7. Electric heater 230 V, A.C.
8. The sensing bulb of low temperature thermostat.
9. A high temperature thermostat.

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10. A Thermometer to measure the chilled water temperature
C. The front panel on which are mounted the following
11. Capillary expansion tube with isolating valve.
12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator
and isolating valve

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13. Drier cum strainer and sight glass
14. Thermostat at inlet and outlet of both evaporator and condenser
15. Pressure gauge at inlet and outlet of evaporator and condenser
16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out
17. Heat power regulator switch and regulator

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18. Energy meter to measure the power consumed either by hater or by compressor.


FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart

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and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION

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VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence

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To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design

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products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies

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5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering

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2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools

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6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms

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9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder

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4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant

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9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system

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12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection

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experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.

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12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC

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Boiler.



COURSE OBJECTIVES

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COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS

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1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11

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3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21

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5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31

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7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47

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CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14

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Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate

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method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters

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together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples

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No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2

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(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help

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of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:

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1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm

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6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100

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0
C
9. Maximum temperature of the hot plate = 170
0
C

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10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V

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15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0

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C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:
Sl. No. Voltmeter
V

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Ammeter
A
Main heater (
0
C) Test Plate (

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0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:

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1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single

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phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.

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8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.

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3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?

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8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?

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13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?

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18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:

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To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple

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(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.

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There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.

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4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.

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4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging

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k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:

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Sl.
No.
Voltage
(V)
Current

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(A)
Heater Temperature
(
0
C)

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Asbestos Temperature
(
0
C)
Saw dust

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Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos

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layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:

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The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)

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6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?

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11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.

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16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical

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tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which

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in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.

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The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Schematic view of the test set-up:

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mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch

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Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples

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6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}

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Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W

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Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L
3

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?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v
2

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is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid

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v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity

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?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.

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hL / k = 0.56 (Gr.Pr)
0.25
for 10
4
< Gr.Pr.<10

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8

hL / k = 0.13 (Gr.Pr)
1/3
for 10

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8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).

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3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:

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The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m

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2
K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing

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heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?

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5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)

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10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness

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15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?

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20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:

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To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer

Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air

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stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of

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orifice meter and the water manometer fitted on the board.


24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

Sl. No. Voltage Current Temperature in (

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0
C)
Manometer
reading of water
in h in meter

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(V) (A)
T1

T2

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T3

T4

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T5

T6

h1

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cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor

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5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0
C

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(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:

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1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.

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6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.

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2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. The rate at which air is getting heated is calculated as

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qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o

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C)
= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate

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Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m
3
/hr

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3. ha = qa /A(Ts- Ta) W / m
2
K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m

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2

Ta = Average temperature of air = (T1 + T6)/2
o
C

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Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C
Cd = 0.64
H = Difference of water level in manometer m

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?w Density of water = 1000 Kg/m
3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

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d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

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using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2

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)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o
C

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5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

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27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k

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? = Viscosity Ns/m
2

k = Thermal conductivity of fluid W/m
2

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K
Nu = 0.023 (Re)
0.8
(Pr)
0.4

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Bulk mean temperature = (T1 + T6)/2

Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.

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hactual = -------------- W/m
2
K
htheoritical = -------------- W/m
2

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K

Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?

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3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?

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8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection

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13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

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Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,

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the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure

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temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat

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flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm

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2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.

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2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

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30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature

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gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:

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Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R

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Tabulation:
Sl.No. Voltmeter
reading
(V)
Ammeter

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reading
(A)
T1
(
0

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C)
T2
(
0
C)

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T3
(
0
C)
T4

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(
0
C)
T5
(

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0
C)
T6
(
0

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C)
T7
(
0
C)

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T8
(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Composite wall apparatus set-up

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Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W

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c. Asbestos section = ------------W

Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure

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Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?

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5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.

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9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

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33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

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DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

Aim:
To find out the thermal conductivity of insulating powder by conduction

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Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A

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multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

Procedure:

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1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.

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5. Repeat the experiments for different power inputs.


The readings are tabulated below

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Sl.No. Voltmeter
reading( V)
Ammeter
reading (A)
T1

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(
0
C)
T2
(

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0
C)
T3
(
0

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C)
T4
(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm

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The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Fig. 1 Apparatus of thermal conductivity of insulating powder

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[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

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Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam

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boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity

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3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.

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8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?

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13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?

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18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

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HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

Aim:

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To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is

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measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:
Sl.

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No.
V I

Fin Temperatures (
0

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C)
Ambient Temp
(
0
C)

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Manometer
Reading
(V)

(A)

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T1 T2 T3 T4 T5 T6 T7 T8
h1
cm
h2

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cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Duct size = 150 mm x 100 mm.

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2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

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Schematic view of the test set-up:



zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5

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10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C
12. Temperature indicator = 0 ? 300

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0
C
(With compensation of ambient temperature up-to 50
0
C)

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13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8

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Brass Pin Fin
Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.

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4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:

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Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.

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4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2

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Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m

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3
/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m

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3

?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s

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2

Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s

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Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

A = area of the duct

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4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.

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(T1 + T6) / 2
o
C
5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number

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6. Nusselt Number:
Nu = CRe
m
(Pr)
0.33

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7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk
m= ?(hp/kA)

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A = area of fin = (? x D
2
) /4
L = Length of the fin
Tw ? average temperature

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T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________

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Heat transfer, Q = ___________ W

Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.


40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer

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6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?

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11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.8

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DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

Aim:

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To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch

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(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water

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between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.

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When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere

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3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg

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8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C
= (or) 0.1 Kcal / kg
0

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C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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11. Temperature indicator digital 0.1
0
C L.C 0 - 200
0

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C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water
Precautions:

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Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4

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? Td
4
)
Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)

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Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

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43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulations:
Proc
edur

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e:
1. H
eat the
water
in the

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tank by
the immersion heater up to a temperature of about 90
0
C.
2. Remove the disc, D before pouring the hot water in the jacket.

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3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.

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6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m

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2
k
4
.

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Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using

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boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

Sl. No.

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Hemisphere Temperature(
0
C) Avg. Temp.
of the
Hemisphere

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(Th)
T4
Steady
Temp. of
Disc

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T0 (Td)
Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number
5. State Wien?s displacement law.

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6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation
10. What are the various modes of condensation?

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11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.9

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DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

Aim:

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To measure emissivity of the test plate surface at various temperature
Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The

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temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.
Specifications:
1. Heater input to black plate W1 = V1 x I1 W

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2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V

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6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300

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0
C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.

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Tabulation:
Sl.
No
Voltage

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Current

Black body
temp(
0

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C)
Avg.
temp.

Polished body

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temp (
0
C)
Avg.
temp.

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Enclosure
Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts

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4
? Ta
4
) A
Eb ? E = (W1 ? W2) / ? (Ts

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4
? Ta
4
) A
E = Eb ? {(W1 ? W2) / ? (Ts

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4
? Ta
4
) A}
Where,

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W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd
2
m

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2

T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)

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Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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? = Stefan boltzman constant = 5.67 x 10
-8
W/m
2
K

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4


Schematic view of the test set-up:

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Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by

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the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

Results:

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The emissivity of the test plate surface is found to be _____________.
Outcome:
From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

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48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Emissivity
2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?

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4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?
6. What is meant by shape factor?
7. Define ? Radiation
8. What is meant by monochromatic emissive power?

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9. Define ? Emissive Power
10. What is meant by absorptivity?
11. Define ? Black Body
12. What is meant by transmissivity?
13. State Plank's distribution law

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14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

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49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.10

EFFECTIVENESS OF PARALLEL / COUNTER

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FLOW HEAT EXCHANGE

Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:

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(i) Experimental Setup
(ii) Stop watch
(iii) Thermometer
Theory:
Heat exchangers are classified in three categories:

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1. Transfer type
2. Storage type
3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.

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The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water

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which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:

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1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50

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0
C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100
0
C - 2 Nos.

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7. Measuring flask = 0 ? 1000 CC

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8. Geyser: single phase type to obtain hot water supply

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9. Thermo Cole insulation for outer pipe.
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Tabulations:

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Sl.
No.
Flow Hot Fluid (
0
C) Cold Fluid (

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0
C)
Time for
collection of
hot fluid

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Kg/sec
Time for
collection
of cold fluid
Kg/sec

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1 Parallel flow
Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)

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1. Area of the pipe A = ? (D ? d) L
Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube
L = Length of the tube

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2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

51 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Where, m = mass flow rate Kg/ sec.

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m = ?v/t, ? = density of water and t = time taken for hot water
Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet
Tho = Temperature of hot water outlet

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3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W
Where, m = mass flow rate
Cp = Specific heat of capacity
Tco = Temperature of cold water inlet
Tci = Temperature of cold water outlet

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4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W
Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)
?Tm = (?Ti - ?To) / In (?Ti/?To)
Where, ?To = Tho ? Tco

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?Ti = Thi ? Tci
6. Over all heat transfer coefficient
h = Q?/?Tm A W/m
2
K

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where Q? = (Qa + Qc) / 2

Procedure:
1. Place the thermometers in position and note down their readings when they are at room temperature and
no water is flowing at either side. This is required to correct the temperature.

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2. Start the flow on hot water side.
3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.
5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.
6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.

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7. Keeping the flow rates same, wait till the steady state conditions are reached.
8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.
10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

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52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Result:
1. The values of effectiveness of heat exchanger were found as

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(i) Parallel flow = ________.
(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)
(i) Parallel flow = ________.
(ii) Counter flow = _________.

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Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow
heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat
exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Heat Exchanger
2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?
4. Write about the merits of drop wise condensation.
5. What is meant by film wise and drop wise condensation?

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6. What is meant by effectiveness?
7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?
9. Distinguish between regenerator and recuperates.
10. What is meant by parallel flow heat exchanger?

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11. What is meant by counter flow heat exchanger?
12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?
Viva ? voce

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53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.11

DETERMINATION OF COP OF A REFRIGERATION

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SYSTEM

Aim:
To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration
system

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Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Experimental setup

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Description:
1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a
reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.
2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated
wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a

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low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the
temperature of chilled water. The above unit is located on the trolley behind front panel.
3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic
expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum
strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure

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gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high
pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy
meter to measure the power consumed either by hater or by compressor.

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54 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
A. A compressor condenser unit placed inside trolley and fitted with
1. R-134a reciprocating compressor
2. Condenser

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3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan
4. A receiver with angle check valve
B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity
placed inside a well insulated wooden box and provided with
5. Evaporator coil

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6. Stirrer
7. Electric heater 230 V, A.C.
8. The sensing bulb of low temperature thermostat.
9. A high temperature thermostat.
10. A Thermometer to measure the chilled water temperature

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C. The front panel on which are mounted the following
11. Capillary expansion tube with isolating valve.
12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator
and isolating valve
13. Drier cum strainer and sight glass

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14. Thermostat at inlet and outlet of both evaporator and condenser
15. Pressure gauge at inlet and outlet of evaporator and condenser
16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out
17. Heat power regulator switch and regulator
18. Energy meter to measure the power consumed either by hater or by compressor.

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55 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.
2. The heater regulator should be switched off whenever not in use. Heating water beyond 40
0
C may lead to

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permanent damage of the entire system. A high temperature cut off thermostat is provided in the water
chiller, to cut off the heater beyond 30
0
C.Check the setting of the same before operation.
3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.

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4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.
5. The solenoid thermostat is adjusted to cut at 15
0
C and cut in at 10
0

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C of the chilled water. Do not alter the
same.
6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.
7. The space near the condenser should permit good ventilation to aid proper fan performance.
8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked

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in
0
F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,
calibrated in SI units, are not available.)
9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to

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obtain the pressure in MN/m
2
.e.g. P = x psig
= (x + 14.7) psia
= (x + 14.7) / 145 MN/m

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2
(MPa)
10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.
Formulae used:
Let, State 1 indicates the entry of compressor.

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State 2 indicates the exit of compressor.
State 3 indicates the exit from condenser.
State 4 indicates the entry to evaporator
P = Pressure (bar)
T = Temperature (

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0
C)
H = Specific enthalpy (kJ/kg)
v = Specific Volume (m
3

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/Kg)
n = Number of revolutions of energy meter disc.
t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)
t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)
K = Energy meter constant = 3200 lmp / kWh

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N = Speed of compressor = 2840 rpm
h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)
FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION

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MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex

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software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills

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4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning

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To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the

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career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society

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7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with

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coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:

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HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube

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5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface

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10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes

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13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.

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4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system

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13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES

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CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6

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2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3

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Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5

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Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7

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Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS

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11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68

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15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT

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USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate

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assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The

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heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:

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1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2

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Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently

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5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm

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2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm

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7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100
0

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C
9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm

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11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A

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16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C

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19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter
V
Ammeter

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A
Main heater (
0
C) Test Plate (
0

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C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.

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Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.

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4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.

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4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?

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9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?

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14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?

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19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF

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PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus

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Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter

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(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm

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5. The effective length of the above = 500 mm

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Precautions:

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1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W

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Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material

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k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.

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No.
Voltage
(V)
Current
(A)

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Heater Temperature
(
0
C)
Asbestos Temperature

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(
0
C)
Saw dust
Temperature (

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0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.

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2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.

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6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.

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The thermal conductivity of resistive material = _________________ W /m
2
-K

Outcome:

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From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:

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Exhaust pipe lines, IC engines, heat exchangers

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1. Define ? Nusselt Number(Nu)

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2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)

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7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?

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12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?

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17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION

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FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The

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temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold

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fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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Schematic view of the test set-up:
mm

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mm

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Specifications:

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1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.

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5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A

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7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

Tabulation:

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Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m

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2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (

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0
C) ?
2. hL / k = A { g L
3
?T Cp ?/2v

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2
}
n

Where, hL / k are called Nusselt Number.

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L
3
g?T / v
2
is called Grashof number.

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?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid

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? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta

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For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)

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0.25
for 10
4
< Gr.Pr.<10
8

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hL / k = 0.13 (Gr.Pr)
1/3
for 10
8

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< Gr.Pr.<10
12
Here, L = Length of the cylinder

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.

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4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as

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Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m
2

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K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC

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engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?

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6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?

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11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.

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16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to

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the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

Sl. No. Voltage Current Temperature in (
0

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C)
Manometer
reading of water
in h in meter

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(V) (A)
T1

T2

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T3

T4

T5

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T6

h1
cm

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h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer

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6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0
C
(Calibrated for chromel alumel thermocouple)

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8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.

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7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat

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input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)

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Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o
C)

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= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di

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2
?2gH x (?w / ?a) m
3
/hr
3. ha = qa /A(Ts- Ta) W / m

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2
K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

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Ta = Average temperature of air = (T1 + T6)/2
o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4

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o
C
Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m

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3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

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d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

using this procedure obtain the value of ?ha? for different air flow rate

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4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2
)/4]

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v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o
C
5. Nusselt Number:

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Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

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27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m

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2

k = Thermal conductivity of fluid W/m
2
K

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Nu = 0.023 (Re)
0.8
(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

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Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m

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2
K
htheoritical = -------------- W/m
2
K

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Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?

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4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?

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9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.

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14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

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29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

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Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the

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thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The

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temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is

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the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm

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3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat

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input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

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30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.

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7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow

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R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:

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Sl.No. Voltmeter
reading
(V)
Ammeter
reading

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(A)
T1
(
0
C)

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T2
(
0
C)
T3

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(
0
C)
T4
(

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0
C)
T5
(
0

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C)
T6
(
0
C)

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T7
(
0
C)
T8

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(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Composite wall apparatus set-up

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Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

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Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal

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conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?

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10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

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33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY

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OF INSULATING POWDER

Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

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The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit

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is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

Procedure:

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1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter

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reading( V)
Ammeter
reading (A)
T1
(

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0
C)
T2
(
0

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C)
T3
(
0
C)

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T4
(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1

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Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.


34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Fig. 1 Apparatus of thermal conductivity of insulating powder

[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater

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control]

Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

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Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to

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be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?

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4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?

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9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)

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14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?

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19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

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36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

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HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:

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A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is

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shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:
Sl.
No.

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V I

Fin Temperatures (
0
C)

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Ambient Temp
(
0
C)
Manometer

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Reading
(V)

(A)

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T1 T2 T3 T4 T5 T6 T7 T8
h1
cm
h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm

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3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.

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11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C
12. Temperature indicator = 0 ? 300
0

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C
(With compensation of ambient temperature up-to 50
0
C)
13. Dimmer stat for heat input controls 230 V, 2 A

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14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8
Brass Pin Fin

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Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

16. Ammeter = 0 ? 2 A

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.

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5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:
Forced Convection:

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1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient

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temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)

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Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m
3

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/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m
3

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?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s
2

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Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

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39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

A = area of the duct
4. Reynold?s Number:

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Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2

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o
C
5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number
6. Nusselt Number:

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Nu = CRe
m
(Pr)
0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)

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h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk
m= ?(hp/kA)
A = area of fin = (? x D

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2
) /4
L = Length of the fin
Tw ? average temperature
T? ? ambient (surface) temperature (T6)

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8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

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Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through

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pin-fin is to be found.


40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Extended Surface

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2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer
6. Define ? Fin Efficiency

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7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?
11. Define ? Convection

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12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

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41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.8

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DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus

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Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Geyser water

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Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to

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measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response

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of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm

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4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg

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0
C
= (or) 0.1 Kcal / kg
0
C

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9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

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11. Temperature indicator digital 0.1
0
C L.C 0 - 200
0
C with built-in cold junction compensation and a timer set

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for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically

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there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4
? Td

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4
)
Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0

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dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

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Tabulations:
Proc
edur
e:

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1. H
eat the
water
in the
tank by

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the immersion heater up to a temperature of about 90
0
C.
2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.

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4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate

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thermocouple).

Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m
2

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k
4
.

Outcome:

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From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.

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.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

Sl. No.
Hemisphere Temperature(

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0
C) Avg. Temp.
of the
Hemisphere
(Th)

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T4
Steady
Temp. of
Disc
T0 (Td)

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Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]

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2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number
5. State Wien?s displacement law.
6. What is the significance of Biot Number?

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7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation
10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]

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12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

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45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.9

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DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

Aim:
To measure emissivity of the test plate surface at various temperature

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:

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The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp

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black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.
Specifications:
1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W

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3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A

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7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300
0

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C.

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Use proper voltage range on Voltmeter.

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3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.
Tabulation:

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Sl.
No
Voltage

Current

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Black body
temp(
0
C)

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Avg.
temp.

Polished body
temp (

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0
C)
Avg.
temp.

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Enclosure
Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts
4

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? Ta
4
) A
Eb ? E = (W1 ? W2) / ? (Ts
4

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? Ta
4
) A
E = Eb ? {(W1 ? W2) / ? (Ts
4

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? Ta
4
) A}
Where,
W1 = Heater input to black plate = V1 x I1 W

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W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd
2
m
2

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T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)
Eb = Emissivity of black plate = 1

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E = Emissivity of Test plate

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? = Stefan boltzman constant = 5.67 x 10

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-8
W/m
2
K
4

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Schematic view of the test set-up:

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Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by
the dimmer stat so that the two plates will be maintained at the same temperature.

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3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

Results:
The emissivity of the test plate surface is found to be _____________.

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Outcome:
From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Emissivity
2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?
4. State Lambert?s cosine law.

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5. What is the purpose of radiation shield?
6. What is meant by shape factor?
7. Define ? Radiation
8. What is meant by monochromatic emissive power?
9. Define ? Emissive Power

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10. What is meant by absorptivity?
11. Define ? Black Body
12. What is meant by transmissivity?
13. State Plank's distribution law
14. What is meant by gray body?

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15. Define ? Irradiation

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Viva ? voce

49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.10

EFFECTIVENESS OF PARALLEL / COUNTER
FLOW HEAT EXCHANGE

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Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:
(i) Experimental Setup

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(ii) Stop watch
(iii) Thermometer
Theory:
Heat exchangers are classified in three categories:
1. Transfer type

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2. Storage type
3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.
The transfer type exchangers are further classified accordant to flow arrangements as:

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i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water
which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water

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flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:
1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm

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2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50
0

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C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100
0
C - 2 Nos.
7. Measuring flask = 0 ? 1000 CC

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8. Geyser: single phase type to obtain hot water supply
9. Thermo Cole insulation for outer pipe.

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Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Tabulations:
Sl.

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No.
Flow Hot Fluid (
0
C) Cold Fluid (
0

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C)
Time for
collection of
hot fluid
Kg/sec

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Time for
collection
of cold fluid
Kg/sec
1 Parallel flow

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Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)
1. Area of the pipe A = ? (D ? d) L

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Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube
L = Length of the tube

2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

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Where, m = mass flow rate Kg/ sec.
m = ?v/t, ? = density of water and t = time taken for hot water

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Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet
Tho = Temperature of hot water outlet

3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W

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Where, m = mass flow rate
Cp = Specific heat of capacity
Tco = Temperature of cold water inlet
Tci = Temperature of cold water outlet
4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W

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Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)
?Tm = (?Ti - ?To) / In (?Ti/?To)
Where, ?To = Tho ? Tco
?Ti = Thi ? Tci

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6. Over all heat transfer coefficient
h = Q?/?Tm A W/m
2
K
where Q? = (Qa + Qc) / 2

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Procedure:
1. Place the thermometers in position and note down their readings when they are at room temperature and
no water is flowing at either side. This is required to correct the temperature.
2. Start the flow on hot water side.

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3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.
5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.
6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.
7. Keeping the flow rates same, wait till the steady state conditions are reached.

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8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.
10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

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Result:
1. The values of effectiveness of heat exchanger were found as
(i) Parallel flow = ________.

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(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)
(i) Parallel flow = ________.
(ii) Counter flow = _________.

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Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow
heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat
exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.
Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.



1. Define ? Heat Exchanger

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2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?
4. Write about the merits of drop wise condensation.
5. What is meant by film wise and drop wise condensation?
6. What is meant by effectiveness?

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7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?
9. Distinguish between regenerator and recuperates.
10. What is meant by parallel flow heat exchanger?
11. What is meant by counter flow heat exchanger?

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12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?
Viva ? voce

53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.11

DETERMINATION OF COP OF A REFRIGERATION
SYSTEM

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Aim:
To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration
system
Apparatus required:

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(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Experimental setup
Description:

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1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a
reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.
2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated
wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a
low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the

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temperature of chilled water. The above unit is located on the trolley behind front panel.
3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic
expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum
strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure
gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high

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pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy
meter to measure the power consumed either by hater or by compressor.

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Specifications:
A. A compressor condenser unit placed inside trolley and fitted with
1. R-134a reciprocating compressor
2. Condenser
3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan

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4. A receiver with angle check valve
B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity
placed inside a well insulated wooden box and provided with
5. Evaporator coil
6. Stirrer

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7. Electric heater 230 V, A.C.
8. The sensing bulb of low temperature thermostat.
9. A high temperature thermostat.
10. A Thermometer to measure the chilled water temperature
C. The front panel on which are mounted the following

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11. Capillary expansion tube with isolating valve.
12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator
and isolating valve
13. Drier cum strainer and sight glass
14. Thermostat at inlet and outlet of both evaporator and condenser

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15. Pressure gauge at inlet and outlet of evaporator and condenser
16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out
17. Heat power regulator switch and regulator
18. Energy meter to measure the power consumed either by hater or by compressor.

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Precautions:

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1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.
2. The heater regulator should be switched off whenever not in use. Heating water beyond 40
0
C may lead to
permanent damage of the entire system. A high temperature cut off thermostat is provided in the water

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chiller, to cut off the heater beyond 30
0
C.Check the setting of the same before operation.
3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.
4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.

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5. The solenoid thermostat is adjusted to cut at 15
0
C and cut in at 10
0
C of the chilled water. Do not alter the

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same.
6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.
7. The space near the condenser should permit good ventilation to aid proper fan performance.
8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked
in

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0
F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,
calibrated in SI units, are not available.)
9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to
obtain the pressure in MN/m

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2
.e.g. P = x psig
= (x + 14.7) psia
= (x + 14.7) / 145 MN/m
2

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(MPa)
10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.
Formulae used:
Let, State 1 indicates the entry of compressor.
State 2 indicates the exit of compressor.

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State 3 indicates the exit from condenser.
State 4 indicates the entry to evaporator
P = Pressure (bar)
T = Temperature (
0

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C)
H = Specific enthalpy (kJ/kg)
v = Specific Volume (m
3
/Kg)

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n = Number of revolutions of energy meter disc.
t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)
t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)
K = Energy meter constant = 3200 lmp / kWh
N = Speed of compressor = 2840 rpm

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h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

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h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2

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h3 = Specific enthalpy at Pc and T3 (kJ/kg)
h4 = h3
Stroke volume of compressor = (?/ 4) d
2
l = 12.58 x 10

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-6
m
3

1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar

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2. Average condenser pressure, Pc = (P2 + P3) / 2 bar
3. Heater input, Qe = (n / t1) x (3600 / k) kW
4. Compressor input, W = (n / t2) x (3600 / k) kW
5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1
6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)

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7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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FirstRanker.com - FirstRanker's Choice
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?

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DEPARTMENT OF
MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION

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MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex

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software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills

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4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning

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To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the

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career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society

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7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with

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coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:

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HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube

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5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface

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10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes

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13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.

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4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system

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13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES

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CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6

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2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3

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Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5

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Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7

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Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS

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11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68

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15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT

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USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate

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assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The

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heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:

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1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2

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Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently

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5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm

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2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm

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7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100
0

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C
9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm

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11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A

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16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C

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19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter
V
Ammeter

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A
Main heater (
0
C) Test Plate (
0

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C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.

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Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.

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4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.

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4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?

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9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?

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14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?

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19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF

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PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus

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Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter

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(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm

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5. The effective length of the above = 500 mm

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Precautions:

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1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W

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Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material

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k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.

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No.
Voltage
(V)
Current
(A)

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Heater Temperature
(
0
C)
Asbestos Temperature

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(
0
C)
Saw dust
Temperature (

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0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.

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2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.

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6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.

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The thermal conductivity of resistive material = _________________ W /m
2
-K

Outcome:

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From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:

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Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. Define ? Nusselt Number(Nu)

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2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)

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7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?

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12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?

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17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION

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FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The

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temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold

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fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Schematic view of the test set-up:
mm

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mm

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Specifications:

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1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.

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5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A

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7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

Tabulation:

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Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m

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2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (

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0
C) ?
2. hL / k = A { g L
3
?T Cp ?/2v

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2
}
n

Where, hL / k are called Nusselt Number.

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L
3
g?T / v
2
is called Grashof number.

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?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid

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? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta

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For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)

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0.25
for 10
4
< Gr.Pr.<10
8

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hL / k = 0.13 (Gr.Pr)
1/3
for 10
8

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< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.

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4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as

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Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m
2

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K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC

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engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?

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6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?

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11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.

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16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to

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the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

Sl. No. Voltage Current Temperature in (
0

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C)
Manometer
reading of water
in h in meter

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(V) (A)
T1

T2

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T3

T4

T5

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T6

h1
cm

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h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer

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6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0
C
(Calibrated for chromel alumel thermocouple)

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8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.

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7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat

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input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)

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Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o
C)

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= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di

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2
?2gH x (?w / ?a) m
3
/hr
3. ha = qa /A(Ts- Ta) W / m

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2
K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

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Ta = Average temperature of air = (T1 + T6)/2
o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4

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o
C
Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m

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3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

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d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

using this procedure obtain the value of ?ha? for different air flow rate

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4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2
)/4]

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v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o
C
5. Nusselt Number:

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Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

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27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m

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2

k = Thermal conductivity of fluid W/m
2
K

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Nu = 0.023 (Re)
0.8
(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

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Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m

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2
K
htheoritical = -------------- W/m
2
K

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Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?

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4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?

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9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.

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14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

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29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

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Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the

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thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The

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temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is

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the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm

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3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat

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input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

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30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.

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7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow

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R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:

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Sl.No. Voltmeter
reading
(V)
Ammeter
reading

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(A)
T1
(
0
C)

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T2
(
0
C)
T3

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(
0
C)
T4
(

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0
C)
T5
(
0

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C)
T6
(
0
C)

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T7
(
0
C)
T8

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(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Composite wall apparatus set-up

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Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

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Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal

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conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?

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10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

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33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY

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OF INSULATING POWDER

Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

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The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit

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is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

Procedure:

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1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter

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reading( V)
Ammeter
reading (A)
T1
(

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0
C)
T2
(
0

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C)
T3
(
0
C)

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T4
(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1

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Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.


34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Fig. 1 Apparatus of thermal conductivity of insulating powder

[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater

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control]

Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

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Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to

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be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?

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4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?

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9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)

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14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?

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19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

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36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

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HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:

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A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is

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shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:
Sl.
No.

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V I

Fin Temperatures (
0
C)

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Ambient Temp
(
0
C)
Manometer

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Reading
(V)

(A)

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T1 T2 T3 T4 T5 T6 T7 T8
h1
cm
h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm

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3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.

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11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C
12. Temperature indicator = 0 ? 300
0

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C
(With compensation of ambient temperature up-to 50
0
C)
13. Dimmer stat for heat input controls 230 V, 2 A

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14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8
Brass Pin Fin

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Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

16. Ammeter = 0 ? 2 A

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.

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5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:
Forced Convection:

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1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient

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temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)

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Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m
3

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/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m
3

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?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s
2

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Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

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39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

A = area of the duct
4. Reynold?s Number:

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Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2

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o
C
5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number
6. Nusselt Number:

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Nu = CRe
m
(Pr)
0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)

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h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk
m= ?(hp/kA)
A = area of fin = (? x D

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2
) /4
L = Length of the fin
Tw ? average temperature
T? ? ambient (surface) temperature (T6)

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8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

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Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through

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pin-fin is to be found.


40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Extended Surface

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2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer
6. Define ? Fin Efficiency

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7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?
11. Define ? Convection

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12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

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41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.8

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DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus

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Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Geyser water

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Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to

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measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response

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of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm

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4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg

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0
C
= (or) 0.1 Kcal / kg
0
C

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9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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11. Temperature indicator digital 0.1
0
C L.C 0 - 200
0
C with built-in cold junction compensation and a timer set

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for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically

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there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4
? Td

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4
)
Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0

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dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:
Proc
edur
e:

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1. H
eat the
water
in the
tank by

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the immersion heater up to a temperature of about 90
0
C.
2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.

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4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate

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thermocouple).

Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m
2

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k
4
.

Outcome:

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From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.

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.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

Sl. No.
Hemisphere Temperature(

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0
C) Avg. Temp.
of the
Hemisphere
(Th)

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T4
Steady
Temp. of
Disc
T0 (Td)

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Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]

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2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number
5. State Wien?s displacement law.
6. What is the significance of Biot Number?

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7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation
10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]

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12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

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45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.9

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DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

Aim:
To measure emissivity of the test plate surface at various temperature

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:

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The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp

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black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.
Specifications:
1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W

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3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A

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7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300
0

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C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Use proper voltage range on Voltmeter.

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3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.
Tabulation:

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Sl.
No
Voltage

Current

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Black body
temp(
0
C)

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Avg.
temp.

Polished body
temp (

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0
C)
Avg.
temp.

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Enclosure
Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts
4

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? Ta
4
) A
Eb ? E = (W1 ? W2) / ? (Ts
4

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? Ta
4
) A
E = Eb ? {(W1 ? W2) / ? (Ts
4

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? Ta
4
) A}
Where,
W1 = Heater input to black plate = V1 x I1 W

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W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd
2
m
2

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T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)
Eb = Emissivity of black plate = 1

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E = Emissivity of Test plate

47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

? = Stefan boltzman constant = 5.67 x 10

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-8
W/m
2
K
4

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Schematic view of the test set-up:

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Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by
the dimmer stat so that the two plates will be maintained at the same temperature.

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3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

Results:
The emissivity of the test plate surface is found to be _____________.

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Outcome:
From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

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48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Emissivity
2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?
4. State Lambert?s cosine law.

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5. What is the purpose of radiation shield?
6. What is meant by shape factor?
7. Define ? Radiation
8. What is meant by monochromatic emissive power?
9. Define ? Emissive Power

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10. What is meant by absorptivity?
11. Define ? Black Body
12. What is meant by transmissivity?
13. State Plank's distribution law
14. What is meant by gray body?

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15. Define ? Irradiation

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Viva ? voce

49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.10

EFFECTIVENESS OF PARALLEL / COUNTER
FLOW HEAT EXCHANGE

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Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:
(i) Experimental Setup

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(ii) Stop watch
(iii) Thermometer
Theory:
Heat exchangers are classified in three categories:
1. Transfer type

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2. Storage type
3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.
The transfer type exchangers are further classified accordant to flow arrangements as:

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i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water
which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water

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flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:
1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm

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2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50
0

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C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100
0
C - 2 Nos.
7. Measuring flask = 0 ? 1000 CC

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50 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

8. Geyser: single phase type to obtain hot water supply
9. Thermo Cole insulation for outer pipe.

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Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Tabulations:
Sl.

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No.
Flow Hot Fluid (
0
C) Cold Fluid (
0

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C)
Time for
collection of
hot fluid
Kg/sec

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Time for
collection
of cold fluid
Kg/sec
1 Parallel flow

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Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)
1. Area of the pipe A = ? (D ? d) L

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Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube
L = Length of the tube

2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

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51 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Where, m = mass flow rate Kg/ sec.
m = ?v/t, ? = density of water and t = time taken for hot water

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Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet
Tho = Temperature of hot water outlet

3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W

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Where, m = mass flow rate
Cp = Specific heat of capacity
Tco = Temperature of cold water inlet
Tci = Temperature of cold water outlet
4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W

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Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)
?Tm = (?Ti - ?To) / In (?Ti/?To)
Where, ?To = Tho ? Tco
?Ti = Thi ? Tci

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6. Over all heat transfer coefficient
h = Q?/?Tm A W/m
2
K
where Q? = (Qa + Qc) / 2

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Procedure:
1. Place the thermometers in position and note down their readings when they are at room temperature and
no water is flowing at either side. This is required to correct the temperature.
2. Start the flow on hot water side.

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3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.
5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.
6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.
7. Keeping the flow rates same, wait till the steady state conditions are reached.

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8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.
10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Result:
1. The values of effectiveness of heat exchanger were found as
(i) Parallel flow = ________.

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(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)
(i) Parallel flow = ________.
(ii) Counter flow = _________.

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Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow
heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat
exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.
Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.



1. Define ? Heat Exchanger

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2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?
4. Write about the merits of drop wise condensation.
5. What is meant by film wise and drop wise condensation?
6. What is meant by effectiveness?

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7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?
9. Distinguish between regenerator and recuperates.
10. What is meant by parallel flow heat exchanger?
11. What is meant by counter flow heat exchanger?

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12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?
Viva ? voce

53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.11

DETERMINATION OF COP OF A REFRIGERATION
SYSTEM

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Aim:
To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration
system
Apparatus required:

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(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Experimental setup
Description:

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1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a
reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.
2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated
wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a
low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the

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temperature of chilled water. The above unit is located on the trolley behind front panel.
3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic
expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum
strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure
gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high

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pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy
meter to measure the power consumed either by hater or by compressor.

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54 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
A. A compressor condenser unit placed inside trolley and fitted with
1. R-134a reciprocating compressor
2. Condenser
3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan

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4. A receiver with angle check valve
B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity
placed inside a well insulated wooden box and provided with
5. Evaporator coil
6. Stirrer

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7. Electric heater 230 V, A.C.
8. The sensing bulb of low temperature thermostat.
9. A high temperature thermostat.
10. A Thermometer to measure the chilled water temperature
C. The front panel on which are mounted the following

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11. Capillary expansion tube with isolating valve.
12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator
and isolating valve
13. Drier cum strainer and sight glass
14. Thermostat at inlet and outlet of both evaporator and condenser

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15. Pressure gauge at inlet and outlet of evaporator and condenser
16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out
17. Heat power regulator switch and regulator
18. Energy meter to measure the power consumed either by hater or by compressor.

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55 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:

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1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.
2. The heater regulator should be switched off whenever not in use. Heating water beyond 40
0
C may lead to
permanent damage of the entire system. A high temperature cut off thermostat is provided in the water

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chiller, to cut off the heater beyond 30
0
C.Check the setting of the same before operation.
3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.
4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.

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5. The solenoid thermostat is adjusted to cut at 15
0
C and cut in at 10
0
C of the chilled water. Do not alter the

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same.
6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.
7. The space near the condenser should permit good ventilation to aid proper fan performance.
8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked
in

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0
F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,
calibrated in SI units, are not available.)
9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to
obtain the pressure in MN/m

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2
.e.g. P = x psig
= (x + 14.7) psia
= (x + 14.7) / 145 MN/m
2

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(MPa)
10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.
Formulae used:
Let, State 1 indicates the entry of compressor.
State 2 indicates the exit of compressor.

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State 3 indicates the exit from condenser.
State 4 indicates the entry to evaporator
P = Pressure (bar)
T = Temperature (
0

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C)
H = Specific enthalpy (kJ/kg)
v = Specific Volume (m
3
/Kg)

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n = Number of revolutions of energy meter disc.
t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)
t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)
K = Energy meter constant = 3200 lmp / kWh
N = Speed of compressor = 2840 rpm

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h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

56 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2

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h3 = Specific enthalpy at Pc and T3 (kJ/kg)
h4 = h3
Stroke volume of compressor = (?/ 4) d
2
l = 12.58 x 10

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-6
m
3

1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar

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2. Average condenser pressure, Pc = (P2 + P3) / 2 bar
3. Heater input, Qe = (n / t1) x (3600 / k) kW
4. Compressor input, W = (n / t2) x (3600 / k) kW
5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1
6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)

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7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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57 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I


Sl.
No.

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Initial
Temp.
of water

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Final
Temp.
of water
Duration
of exp.

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Delivery
pressure

Delivery

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Temp.

Condense
Outlet
Pressure

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Condense
Outlet
Temp.

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Pressure
after
throttling

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Temp.

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After
Throttli
ng

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Suction
pressur
e
Suction
Temp.

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Time for

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10 rev. of
compress
or energy
meter

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Height
of water
in the

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vessel

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FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________

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Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and

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enterprising professionals conforming to global standards through value based quality education and training.



? To provide competent technical manpower capable of meeting requirements of the industry

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? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING



Rendering the services to the global needs of engineering industries by educating students to become

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professionally sound mechanical engineers of excellent caliber



To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on

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experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION
MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould

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them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth

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To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up

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their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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PROGRAMME OUTCOMES (POs)

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On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications

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4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability

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8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills

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11. To develop and manage projects in multidisciplinary environments

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ME6512 ? THERMAL ENGINEERING LABORATORY ? II



? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the

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performance of refrigeration cycle / components

LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus

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2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder

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7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

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REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System

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15. Performance test in a fluidized Bed Cooling Tower



1. Able to find out the thermal conductivity of various materials.

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2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials

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6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.

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11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures

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14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
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CONTENTS


Sl.No.
Name of the experiment

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Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe

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apparatus
11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder

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15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS

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6
Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39

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9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58

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13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS

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16 Air conditioning test rig 75
PROJECT WORK 81

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Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

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Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup

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(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to

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prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater

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assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved

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aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK

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3. Area, A = ( ?/4) d
2
(10 + x)

cm

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2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.

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2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there

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is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

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Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm

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4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40

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0
C ? 100
0
C
9. Maximum temperature of the hot plate = 170

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0
C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)

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13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)

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18. Temperature indicator = 0 ? 200
0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm

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21. Specimen used = Press wood

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Tabulation:

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Sl. No. Voltmeter
V
Ammeter
A
Main heater (

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0
C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water

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is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from

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thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably

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steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:

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Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded

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hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.

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6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer

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11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?

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16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

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Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup

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(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter
Theory:

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The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in

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the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:
1. Diameter of the heater Rod = 20 mm.

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2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).

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2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by

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Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging

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material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.
No.
Voltage

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(V)
Current
(A)
Heater Temperature
(

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0
C)
Asbestos Temperature
(
0

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C)
Saw dust
Temperature (
0
C)

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T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.

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4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.

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7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2

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-K

Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC

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engines, heat exchangers, etc. where heat transfer is to be found.

Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?

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4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?

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9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?

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14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis

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19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

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Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:
(i) Experimental setup

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(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at

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the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

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When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Schematic view of the test set-up:
mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm

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3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0

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C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V

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9. Heater = Cartridge type (400 W)

Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (

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0
c)

V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:

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1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2
K

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As = Area of heat transfer surface = ? x d x l m
2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0

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C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0
C) ?

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2. hL / k = A { g L
3
?T Cp ?/2v
2
}

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n

Where, hL / k are called Nusselt Number.
L
3

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g?T / v
2
is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.

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Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid

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? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0

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K
-1

Where Tf = (Ts + Ta )/ 2

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For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25
for 10

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4
< Gr.Pr.<10
8

hL / k = 0.13 (Gr.Pr)

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1/3
for 10
8
< Gr.Pr.<10
12

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Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

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Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2

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K
Experimental = ______________ W/ m
2
K

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Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?

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3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?

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8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer

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13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.

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18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No. 4

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

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Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:

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(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

Theory:

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Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat

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supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



Tabulations:

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Sl. No. Voltage Current Temperature in (
0
C)
Manometer

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reading of water
in h in meter

(V) (A)
T1

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T2

T3

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T4

T5

T6

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h1
cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm

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3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300

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0
C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A

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10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.

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4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:

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1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady

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state is reached.
4. Note down the heater input.

26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)

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?T = Temperature rise in air (
o
C)
= T6 ? T1.
2. m = Q?

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Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m

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3
/hr
3. ha = qa /A(Ts- Ta) W / m
2
K

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qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

Ta = Average temperature of air = (T1 + T6)/2

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o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C

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Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

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?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s

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2

using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number

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Where, V = velocity of air = Q/[(? x Di
2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2

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o
C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K

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Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

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k = Thermal conductivity of fluid W/m
2
K
Nu = 0.023 (Re)
0.8

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(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

Results:

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Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m
2
K

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htheoritical = -------------- W/m
2
K

Outcome:

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From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.

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6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?

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11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall

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Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The

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temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus

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uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.

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Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.

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Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.

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4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from

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the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate

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Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter
reading

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(V)
Ammeter
reading
(A)
T1

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(
0
C)
T2
(

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0
C)
T3
(
0

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C)
T4
(
0
C)

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T5
(
0
C)
T6

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(
0
C)
T7
(

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0
C)
T8
(
0

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C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:
The rate of heat transfer through different materials are found to be

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a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

Outcome:

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From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.



32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?

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3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.

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7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?

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12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

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Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between

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the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

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Procedure:

1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.

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3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter
reading( V)
Ammeter

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reading (A)
T1
(
0
C)

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T2
(
0
C)
T3

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(
0
C)
T4
(

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0
C)

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Calculations:

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The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Fig. 1 Apparatus of thermal conductivity of insulating powder

[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

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Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

Outcome:

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From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?

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6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?

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11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection

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16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.7

HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

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Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer
Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of

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the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:

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Forced convection:
Sl.
No.
V I

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Fin Temperatures (
0
C)
Ambient Temp
(

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0
C)
Manometer
Reading
(V)

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(A)

T1 T2 T3 T4 T5 T6 T7 T8
h1

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cm
h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm

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5. Diameter of the delivery pipe (O.D) = 46 mm

Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64

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8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0

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C
12. Temperature indicator = 0 ? 300
0
C
(With compensation of ambient temperature up-to 50

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0
C)
13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V

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T7 T6 T5 T4 T3 T2 T1
T8
Brass Pin Fin
Heater

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38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.

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7. Do not exceed 200 W.
Procedure:
Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.

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2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.

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Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D

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2
) /4}?2gha m
3
/s.
Where, ha (head of air) = (?w / ?a) x H m

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H = Difference of water level in manometer m
?w Density of water = 1000 kg/m
3

?a = Density of air = 1.165 kg/m

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3
g = acceleration due to gravity = 9.81 m/s
2

Cd = Coefficient of discharge = 0.64

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D = diameter of the orifice
3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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A = area of the duct
4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?

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D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2
o
C

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5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number
6. Nusselt Number:
Nu = CRe
m

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(Pr)
0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m

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k= 386 w/mk
m= ?(hp/kA)
A = area of fin = (? x D
2
) /4

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L = Length of the fin
Tw ? average temperature
T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:

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Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

Outcome:

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From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.

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40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.

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4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer
6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction

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9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?
11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?

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14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.8

DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

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Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer

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(ii) Electric Heater
(iii) Stop watch
(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The

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outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A

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chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:

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1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve

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6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C

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= (or) 0.1 Kcal / kg
0
C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

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11. Temperature indicator digital 0.1
0

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C L.C 0 - 200
0
C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW

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13. Tank for hot water
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:

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Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4
? Td
4
)

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Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

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Schematic view of the test set-up:

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Heater

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Tabulations:

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Proc
edur
e:
1. H
eat the

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water
in the
tank by
the immersion heater up to a temperature of about 90
0

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C.
2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant

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cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

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Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m
2
k
4

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.

Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus

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is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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Sl. No.
Hemisphere Temperature(
0
C) Avg. Temp.

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of the
Hemisphere
(Th)
T4
Steady

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Temp. of
Disc
T0 (Td)
Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?
3. State Planck?s distribution law.

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4. Define ? Biot Number
5. State Wien?s displacement law.
6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.
8. What are the various types of convection?

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9. Define ? Condensation
10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?
13. State Krichoff's law or radiation

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14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.9

DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

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Aim:
To measure emissivity of the test plate surface at various temperature
Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer
Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide

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undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.

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Specifications:
1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.

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Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.

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9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300
0
C.

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.

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5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.
Tabulation:
Sl.
No

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Voltage

Current

Black body

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temp(
0
C)
Avg.
temp.

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Polished body
temp (
0
C)

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Avg.
temp.

Enclosure
Temp.

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(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:

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Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts
4
? Ta
4

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) A
Eb ? E = (W1 ? W2) / ? (Ts
4
? Ta
4

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) A
E = Eb ? {(W1 ? W2) / ? (Ts
4
? Ta
4

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) A}
Where,
W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd

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2
m
2

T = Temperature of black plate, k = (Ts + Ta) / 2

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Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)
Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

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47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

? = Stefan boltzman constant = 5.67 x 10
-8
W/m

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2
K
4

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Schematic view of the test set-up:


Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.

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And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by
the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

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Results:
The emissivity of the test plate surface is found to be _____________.
Outcome:
From this experiment, finding the emissivity of the test plate surface at various

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temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Emissivity

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2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?
4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?
6. What is meant by shape factor?

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7. Define ? Radiation
8. What is meant by monochromatic emissive power?
9. Define ? Emissive Power
10. What is meant by absorptivity?
11. Define ? Black Body

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12. What is meant by transmissivity?
13. State Plank's distribution law
14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.10

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EFFECTIVENESS OF PARALLEL / COUNTER
FLOW HEAT EXCHANGE

Aim:

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To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:
(i) Experimental Setup
(ii) Stop watch
(iii) Thermometer

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Theory:
Heat exchangers are classified in three categories:
1. Transfer type
2. Storage type
3. Direct contact type.

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A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.
The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.

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iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water
which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run

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as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:
1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm

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4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50
0
C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100

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0
C - 2 Nos.
7. Measuring flask = 0 ? 1000 CC

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8. Geyser: single phase type to obtain hot water supply
9. Thermo Cole insulation for outer pipe.
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically

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there is no temperature rise in the circuiting fluid.
Tabulations:
Sl.
No.
Flow Hot Fluid (

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0
C) Cold Fluid (
0
C)
Time for

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collection of
hot fluid
Kg/sec
Time for
collection

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of cold fluid
Kg/sec
1 Parallel flow
Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)
1. Area of the pipe A = ? (D ? d) L
Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube

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L = Length of the tube

2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

51 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Where, m = mass flow rate Kg/ sec.
m = ?v/t, ? = density of water and t = time taken for hot water
Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet

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Tho = Temperature of hot water outlet

3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W
Where, m = mass flow rate
Cp = Specific heat of capacity

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Tco = Temperature of cold water inlet
Tci = Temperature of cold water outlet
4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W
Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)

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?Tm = (?Ti - ?To) / In (?Ti/?To)
Where, ?To = Tho ? Tco
?Ti = Thi ? Tci
6. Over all heat transfer coefficient
h = Q?/?Tm A W/m

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2
K
where Q? = (Qa + Qc) / 2

Procedure:

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1. Place the thermometers in position and note down their readings when they are at room temperature and
no water is flowing at either side. This is required to correct the temperature.
2. Start the flow on hot water side.
3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.

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5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.
6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.
7. Keeping the flow rates same, wait till the steady state conditions are reached.
8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.

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10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Result:
1. The values of effectiveness of heat exchanger were found as
(i) Parallel flow = ________.
(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)

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(i) Parallel flow = ________.
(ii) Counter flow = _________.

Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow

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heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat
exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Heat Exchanger
2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?

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4. Write about the merits of drop wise condensation.
5. What is meant by film wise and drop wise condensation?
6. What is meant by effectiveness?
7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?

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9. Distinguish between regenerator and recuperates.
10. What is meant by parallel flow heat exchanger?
11. What is meant by counter flow heat exchanger?
12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?

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Viva ? voce

53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.11

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DETERMINATION OF COP OF A REFRIGERATION
SYSTEM

Aim:

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To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration
system
Apparatus required:
(i) Thermometer
(ii) Electric Heater

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(iii) Stop watch
(iv) Experimental setup
Description:
1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a
reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.

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2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated
wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a
low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the
temperature of chilled water. The above unit is located on the trolley behind front panel.
3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic

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expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum
strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure
gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high
pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy
meter to measure the power consumed either by hater or by compressor.

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54 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
A. A compressor condenser unit placed inside trolley and fitted with

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1. R-134a reciprocating compressor
2. Condenser
3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan
4. A receiver with angle check valve
B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity

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placed inside a well insulated wooden box and provided with
5. Evaporator coil
6. Stirrer
7. Electric heater 230 V, A.C.
8. The sensing bulb of low temperature thermostat.

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9. A high temperature thermostat.
10. A Thermometer to measure the chilled water temperature
C. The front panel on which are mounted the following
11. Capillary expansion tube with isolating valve.
12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator

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and isolating valve
13. Drier cum strainer and sight glass
14. Thermostat at inlet and outlet of both evaporator and condenser
15. Pressure gauge at inlet and outlet of evaporator and condenser
16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out

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17. Heat power regulator switch and regulator
18. Energy meter to measure the power consumed either by hater or by compressor.

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55 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.
2. The heater regulator should be switched off whenever not in use. Heating water beyond 40

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0
C may lead to
permanent damage of the entire system. A high temperature cut off thermostat is provided in the water
chiller, to cut off the heater beyond 30
0

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C.Check the setting of the same before operation.
3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.
4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.
5. The solenoid thermostat is adjusted to cut at 15
0

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C and cut in at 10
0
C of the chilled water. Do not alter the
same.
6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.

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7. The space near the condenser should permit good ventilation to aid proper fan performance.
8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked
in
0
F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,

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calibrated in SI units, are not available.)
9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to
obtain the pressure in MN/m
2
.e.g. P = x psig

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= (x + 14.7) psia
= (x + 14.7) / 145 MN/m
2
(MPa)
10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.

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Formulae used:
Let, State 1 indicates the entry of compressor.
State 2 indicates the exit of compressor.
State 3 indicates the exit from condenser.
State 4 indicates the entry to evaporator

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P = Pressure (bar)
T = Temperature (
0
C)
H = Specific enthalpy (kJ/kg)

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v = Specific Volume (m
3
/Kg)
n = Number of revolutions of energy meter disc.
t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)

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t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)
K = Energy meter constant = 3200 lmp / kWh
N = Speed of compressor = 2840 rpm
h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

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56 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2
h3 = Specific enthalpy at Pc and T3 (kJ/kg)
h4 = h3

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Stroke volume of compressor = (?/ 4) d
2
l = 12.58 x 10
-6
m

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3

1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar
2. Average condenser pressure, Pc = (P2 + P3) / 2 bar
3. Heater input, Qe = (n / t1) x (3600 / k) kW

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4. Compressor input, W = (n / t2) x (3600 / k) kW
5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1
6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)
7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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57 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

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Sl.
No.

Initial

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Temp.
of water

Final
Temp.

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of water
Duration
of exp.

Delivery

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pressure

Delivery
Temp.

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Condense
Outlet
Pressure

Condense

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Outlet
Temp.


Pressure

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after
throttling

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Temp.
After
Throttli

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ng


Suction
pressur

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e
Suction
Temp.

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Time for
10 rev. of
compress

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or energy
meter

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Height
of water
in the
vessel

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58 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
Load Test with Capillary tube as expansion device:
1. Fill the chilled water calorimeter with pure water so that the evaporative coils are
fully immersed.

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2. Select the capillary tube line by opening the shut-off valve on this line and closing
the one on the thermostatic expansion valve line. The solenoid switch is switched OFF.
3. Start the compressor and run for some time so that the chilled water temperature
is lowered to the given test temperature.
4. Switch on the heater and slowly increase the power.

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5. Allow The temperature in water calorimeter to reach the equilibrium
temperature.
6. Connect energy meter to motor and heater by the selector switch one after another
and note down the time taken for 10 pulses of the energy meter disc.
7. Note down the pressure and temperature readings at locations 1,2,3 & 4 as

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mentioned.
8. Switch OFF the heater and the mains.
Result:
The load test on a refrigeration test rig was conducted and the results are as follows.
1. Actual C.O.P. of the system =____________.

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2. Rhetorical C.O.P. of the system = ___________.
3. Volumetric Efficiency = ___________.

Outcome:
From this experiment, conducting the load test on a refrigeration test rig and finding out the

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volumetric efficiency and co-efficient of performance for any type of refrigerant is learnt and this experiment
could be used in the areas such as Refrigerator and Air Conditioning.
Applications:
Refrigerator, Air Conditioning.

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FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________

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Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and

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enterprising professionals conforming to global standards through value based quality education and training.



? To provide competent technical manpower capable of meeting requirements of the industry

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? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING



Rendering the services to the global needs of engineering industries by educating students to become

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professionally sound mechanical engineers of excellent caliber



To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on

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experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould

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them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth

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To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up

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their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME OUTCOMES (POs)

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On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications

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4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability

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8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills

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11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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ME6512 ? THERMAL ENGINEERING LABORATORY ? II



? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the

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performance of refrigeration cycle / components

LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus

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2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder

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7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

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REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System

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15. Performance test in a fluidized Bed Cooling Tower



1. Able to find out the thermal conductivity of various materials.

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2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials

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6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.

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11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures

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14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
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CONTENTS


Sl.No.
Name of the experiment

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Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe

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apparatus
11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder

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15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS

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6
Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39

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9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58

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13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS

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16 Air conditioning test rig 75
PROJECT WORK 81

8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

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Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup

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(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to

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prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater

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assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved

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aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK

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3. Area, A = ( ?/4) d
2
(10 + x)

cm

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2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.

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2. Increase the voltage gradually.

9 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there

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is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

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Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm

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4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40

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0
C ? 100
0
C
9. Maximum temperature of the hot plate = 170

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0
C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)

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13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)

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18. Temperature indicator = 0 ? 200
0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm

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21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:

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Sl. No. Voltmeter
V
Ammeter
A
Main heater (

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0
C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water

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is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from

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thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably

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steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:

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Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded

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hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.

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6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer

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11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?

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16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

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Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup

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(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter
Theory:

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The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in

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the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:
1. Diameter of the heater Rod = 20 mm.

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2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).

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2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by

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Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging

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material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.
No.
Voltage

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(V)
Current
(A)
Heater Temperature
(

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0
C)
Asbestos Temperature
(
0

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C)
Saw dust
Temperature (
0
C)

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T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.

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4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.

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7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2

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-K

Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC

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engines, heat exchangers, etc. where heat transfer is to be found.

Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?

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4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?

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9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?

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14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis

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19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

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Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:
(i) Experimental setup

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(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at

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the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

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When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Schematic view of the test set-up:
mm
mm

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19 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm

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3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0

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C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V

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9. Heater = Cartridge type (400 W)

Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (

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0
c)

V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:

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1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2
K

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As = Area of heat transfer surface = ? x d x l m
2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0

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C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0
C) ?

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2. hL / k = A { g L
3
?T Cp ?/2v
2
}

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n

Where, hL / k are called Nusselt Number.
L
3

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g?T / v
2
is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.

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Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid

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? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0

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K
-1

Where Tf = (Ts + Ta )/ 2

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For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25
for 10

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4
< Gr.Pr.<10
8

hL / k = 0.13 (Gr.Pr)

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1/3
for 10
8
< Gr.Pr.<10
12

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Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

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Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2

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K
Experimental = ______________ W/ m
2
K

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Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?

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3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?

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8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer

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13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.

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18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No. 4

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

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Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:

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(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

Theory:

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Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat

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supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



Tabulations:

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Sl. No. Voltage Current Temperature in (
0
C)
Manometer

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reading of water
in h in meter

(V) (A)
T1

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T2

T3

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T4

T5

T6

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h1
cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm

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3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300

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0
C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A

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10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.

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4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:

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1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady

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state is reached.
4. Note down the heater input.

26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)

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?T = Temperature rise in air (
o
C)
= T6 ? T1.
2. m = Q?

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Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m

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3
/hr
3. ha = qa /A(Ts- Ta) W / m
2
K

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qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

Ta = Average temperature of air = (T1 + T6)/2

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o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C

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Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

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?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s

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2

using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number

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Where, V = velocity of air = Q/[(? x Di
2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2

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o
C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K

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Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

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k = Thermal conductivity of fluid W/m
2
K
Nu = 0.023 (Re)
0.8

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(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

Results:

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Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m
2
K

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htheoritical = -------------- W/m
2
K

Outcome:

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From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.

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6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?

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11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall

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Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The

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temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus

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uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.

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Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.

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Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.

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4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from

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the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate

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Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter
reading

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(V)
Ammeter
reading
(A)
T1

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(
0
C)
T2
(

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0
C)
T3
(
0

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C)
T4
(
0
C)

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T5
(
0
C)
T6

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(
0
C)
T7
(

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0
C)
T8
(
0

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C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:
The rate of heat transfer through different materials are found to be

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a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

Outcome:

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From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.



32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?

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3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.

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7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?

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12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

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Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between

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the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

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Procedure:

1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.

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3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter
reading( V)
Ammeter

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reading (A)
T1
(
0
C)

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T2
(
0
C)
T3

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(
0
C)
T4
(

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0
C)

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Calculations:

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The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Fig. 1 Apparatus of thermal conductivity of insulating powder

[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

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Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

Outcome:

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From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?

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6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?

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11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection

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16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.7

HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

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Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer
Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of

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the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:

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Forced convection:
Sl.
No.
V I

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Fin Temperatures (
0
C)
Ambient Temp
(

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0
C)
Manometer
Reading
(V)

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(A)

T1 T2 T3 T4 T5 T6 T7 T8
h1

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cm
h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm

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5. Diameter of the delivery pipe (O.D) = 46 mm

Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64

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8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0

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C
12. Temperature indicator = 0 ? 300
0
C
(With compensation of ambient temperature up-to 50

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0
C)
13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V

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T7 T6 T5 T4 T3 T2 T1
T8
Brass Pin Fin
Heater

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38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.

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7. Do not exceed 200 W.
Procedure:
Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.

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2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.

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Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D

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2
) /4}?2gha m
3
/s.
Where, ha (head of air) = (?w / ?a) x H m

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H = Difference of water level in manometer m
?w Density of water = 1000 kg/m
3

?a = Density of air = 1.165 kg/m

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3
g = acceleration due to gravity = 9.81 m/s
2

Cd = Coefficient of discharge = 0.64

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D = diameter of the orifice
3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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A = area of the duct
4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?

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D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2
o
C

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5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number
6. Nusselt Number:
Nu = CRe
m

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(Pr)
0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m

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k= 386 w/mk
m= ?(hp/kA)
A = area of fin = (? x D
2
) /4

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L = Length of the fin
Tw ? average temperature
T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:

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Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

Outcome:

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From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.

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40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.

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4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer
6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction

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9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?
11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?

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14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.8

DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

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Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer

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(ii) Electric Heater
(iii) Stop watch
(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The

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outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A

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chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:

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1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve

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6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C

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= (or) 0.1 Kcal / kg
0
C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

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42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

11. Temperature indicator digital 0.1
0

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C L.C 0 - 200
0
C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW

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13. Tank for hot water
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:

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Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4
? Td
4
)

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Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

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Schematic view of the test set-up:

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Heater

43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulations:

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Proc
edur
e:
1. H
eat the

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water
in the
tank by
the immersion heater up to a temperature of about 90
0

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C.
2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant

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cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

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Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m
2
k
4

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.

Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus

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is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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Sl. No.
Hemisphere Temperature(
0
C) Avg. Temp.

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of the
Hemisphere
(Th)
T4
Steady

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Temp. of
Disc
T0 (Td)
Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?
3. State Planck?s distribution law.

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4. Define ? Biot Number
5. State Wien?s displacement law.
6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.
8. What are the various types of convection?

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9. Define ? Condensation
10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?
13. State Krichoff's law or radiation

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14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.9

DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

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Aim:
To measure emissivity of the test plate surface at various temperature
Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer
Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide

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undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.

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Specifications:
1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.

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Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.

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9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300
0
C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.

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5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.
Tabulation:
Sl.
No

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Voltage

Current

Black body

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temp(
0
C)
Avg.
temp.

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Polished body
temp (
0
C)

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Avg.
temp.

Enclosure
Temp.

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(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:

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Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts
4
? Ta
4

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) A
Eb ? E = (W1 ? W2) / ? (Ts
4
? Ta
4

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) A
E = Eb ? {(W1 ? W2) / ? (Ts
4
? Ta
4

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) A}
Where,
W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd

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2
m
2

T = Temperature of black plate, k = (Ts + Ta) / 2

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Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)
Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

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47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

? = Stefan boltzman constant = 5.67 x 10
-8
W/m

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2
K
4

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Schematic view of the test set-up:


Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.

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And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by
the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

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Results:
The emissivity of the test plate surface is found to be _____________.
Outcome:
From this experiment, finding the emissivity of the test plate surface at various

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temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Emissivity

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2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?
4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?
6. What is meant by shape factor?

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7. Define ? Radiation
8. What is meant by monochromatic emissive power?
9. Define ? Emissive Power
10. What is meant by absorptivity?
11. Define ? Black Body

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12. What is meant by transmissivity?
13. State Plank's distribution law
14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.10

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EFFECTIVENESS OF PARALLEL / COUNTER
FLOW HEAT EXCHANGE

Aim:

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To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:
(i) Experimental Setup
(ii) Stop watch
(iii) Thermometer

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Theory:
Heat exchangers are classified in three categories:
1. Transfer type
2. Storage type
3. Direct contact type.

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A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.
The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.

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iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water
which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run

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as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:
1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm

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4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50
0
C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100

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0
C - 2 Nos.
7. Measuring flask = 0 ? 1000 CC

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8. Geyser: single phase type to obtain hot water supply
9. Thermo Cole insulation for outer pipe.
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically

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there is no temperature rise in the circuiting fluid.
Tabulations:
Sl.
No.
Flow Hot Fluid (

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0
C) Cold Fluid (
0
C)
Time for

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collection of
hot fluid
Kg/sec
Time for
collection

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of cold fluid
Kg/sec
1 Parallel flow
Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)
1. Area of the pipe A = ? (D ? d) L
Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube

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L = Length of the tube

2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

51 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Where, m = mass flow rate Kg/ sec.
m = ?v/t, ? = density of water and t = time taken for hot water
Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet

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Tho = Temperature of hot water outlet

3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W
Where, m = mass flow rate
Cp = Specific heat of capacity

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Tco = Temperature of cold water inlet
Tci = Temperature of cold water outlet
4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W
Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)

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?Tm = (?Ti - ?To) / In (?Ti/?To)
Where, ?To = Tho ? Tco
?Ti = Thi ? Tci
6. Over all heat transfer coefficient
h = Q?/?Tm A W/m

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2
K
where Q? = (Qa + Qc) / 2

Procedure:

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1. Place the thermometers in position and note down their readings when they are at room temperature and
no water is flowing at either side. This is required to correct the temperature.
2. Start the flow on hot water side.
3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.

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5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.
6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.
7. Keeping the flow rates same, wait till the steady state conditions are reached.
8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.

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10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Result:
1. The values of effectiveness of heat exchanger were found as
(i) Parallel flow = ________.
(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)

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(i) Parallel flow = ________.
(ii) Counter flow = _________.

Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow

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heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat
exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Heat Exchanger
2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?

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4. Write about the merits of drop wise condensation.
5. What is meant by film wise and drop wise condensation?
6. What is meant by effectiveness?
7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?

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9. Distinguish between regenerator and recuperates.
10. What is meant by parallel flow heat exchanger?
11. What is meant by counter flow heat exchanger?
12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?

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Viva ? voce

53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.11

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DETERMINATION OF COP OF A REFRIGERATION
SYSTEM

Aim:

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To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration
system
Apparatus required:
(i) Thermometer
(ii) Electric Heater

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(iii) Stop watch
(iv) Experimental setup
Description:
1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a
reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.

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2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated
wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a
low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the
temperature of chilled water. The above unit is located on the trolley behind front panel.
3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic

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expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum
strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure
gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high
pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy
meter to measure the power consumed either by hater or by compressor.

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54 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
A. A compressor condenser unit placed inside trolley and fitted with

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1. R-134a reciprocating compressor
2. Condenser
3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan
4. A receiver with angle check valve
B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity

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placed inside a well insulated wooden box and provided with
5. Evaporator coil
6. Stirrer
7. Electric heater 230 V, A.C.
8. The sensing bulb of low temperature thermostat.

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9. A high temperature thermostat.
10. A Thermometer to measure the chilled water temperature
C. The front panel on which are mounted the following
11. Capillary expansion tube with isolating valve.
12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator

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and isolating valve
13. Drier cum strainer and sight glass
14. Thermostat at inlet and outlet of both evaporator and condenser
15. Pressure gauge at inlet and outlet of evaporator and condenser
16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out

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17. Heat power regulator switch and regulator
18. Energy meter to measure the power consumed either by hater or by compressor.

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55 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.
2. The heater regulator should be switched off whenever not in use. Heating water beyond 40

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0
C may lead to
permanent damage of the entire system. A high temperature cut off thermostat is provided in the water
chiller, to cut off the heater beyond 30
0

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C.Check the setting of the same before operation.
3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.
4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.
5. The solenoid thermostat is adjusted to cut at 15
0

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C and cut in at 10
0
C of the chilled water. Do not alter the
same.
6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.

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7. The space near the condenser should permit good ventilation to aid proper fan performance.
8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked
in
0
F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,

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calibrated in SI units, are not available.)
9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to
obtain the pressure in MN/m
2
.e.g. P = x psig

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= (x + 14.7) psia
= (x + 14.7) / 145 MN/m
2
(MPa)
10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.

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Formulae used:
Let, State 1 indicates the entry of compressor.
State 2 indicates the exit of compressor.
State 3 indicates the exit from condenser.
State 4 indicates the entry to evaporator

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P = Pressure (bar)
T = Temperature (
0
C)
H = Specific enthalpy (kJ/kg)

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v = Specific Volume (m
3
/Kg)
n = Number of revolutions of energy meter disc.
t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)

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t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)
K = Energy meter constant = 3200 lmp / kWh
N = Speed of compressor = 2840 rpm
h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

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56 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2
h3 = Specific enthalpy at Pc and T3 (kJ/kg)
h4 = h3

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Stroke volume of compressor = (?/ 4) d
2
l = 12.58 x 10
-6
m

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3

1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar
2. Average condenser pressure, Pc = (P2 + P3) / 2 bar
3. Heater input, Qe = (n / t1) x (3600 / k) kW

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4. Compressor input, W = (n / t2) x (3600 / k) kW
5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1
6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)
7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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57 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

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Sl.
No.

Initial

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Temp.
of water

Final
Temp.

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of water
Duration
of exp.

Delivery

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pressure

Delivery
Temp.

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Condense
Outlet
Pressure

Condense

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Outlet
Temp.


Pressure

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after
throttling

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Temp.
After
Throttli

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ng


Suction
pressur

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e
Suction
Temp.

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Time for
10 rev. of
compress

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or energy
meter

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Height
of water
in the
vessel

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58 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
Load Test with Capillary tube as expansion device:
1. Fill the chilled water calorimeter with pure water so that the evaporative coils are
fully immersed.

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2. Select the capillary tube line by opening the shut-off valve on this line and closing
the one on the thermostatic expansion valve line. The solenoid switch is switched OFF.
3. Start the compressor and run for some time so that the chilled water temperature
is lowered to the given test temperature.
4. Switch on the heater and slowly increase the power.

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5. Allow The temperature in water calorimeter to reach the equilibrium
temperature.
6. Connect energy meter to motor and heater by the selector switch one after another
and note down the time taken for 10 pulses of the energy meter disc.
7. Note down the pressure and temperature readings at locations 1,2,3 & 4 as

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mentioned.
8. Switch OFF the heater and the mains.
Result:
The load test on a refrigeration test rig was conducted and the results are as follows.
1. Actual C.O.P. of the system =____________.

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2. Rhetorical C.O.P. of the system = ___________.
3. Volumetric Efficiency = ___________.

Outcome:
From this experiment, conducting the load test on a refrigeration test rig and finding out the

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volumetric efficiency and co-efficient of performance for any type of refrigerant is learnt and this experiment
could be used in the areas such as Refrigerator and Air Conditioning.
Applications:
Refrigerator, Air Conditioning.

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59 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? COP
2. Which thermodynamic cycle is used in air conditioning of airplanes using air as refrigerant?
3. Define ? Ton of Refrigeration

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4. What is meant by refrigeration?
5. What is meant by air conditioning?
6. What are the four important properties of a good refrigerant?
7. How does the actual vapour compression cycle differ from that of the ideal cycle?
8. Name any four commonly used refrigerants.

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9. What are the expansion devices used in a vapour compression plant?
10. Why throttle valve is used in place of expansion cylinder for vapour compression refrigerant machine?
11. What are the merits of air refrigeration system?
12. What are the demerits of air refrigeration system?
13. Define ? Refrigerant

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14. What is net refrigerating effect of the refrigerant?
15. What are the methods to obtain sub cooling of refrigerant?

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Viva ? voce
FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart

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and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION

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VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence

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To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design

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products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies

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5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering

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2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools

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6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms

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9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder

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4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant

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9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system

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12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection

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experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.

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12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC

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Boiler.



COURSE OBJECTIVES

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COURSE OUTCOMES
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CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS

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1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11

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3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21

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5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31

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7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47

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CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14

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Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate

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method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters

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together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples

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No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2

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(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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9 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help

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of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:

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1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm

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6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100

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0
C
9. Maximum temperature of the hot plate = 170
0
C

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10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V

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15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0

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C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:
Sl. No. Voltmeter
V

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Ammeter
A
Main heater (
0
C) Test Plate (

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0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:

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1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single

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phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.

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8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.

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3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?

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8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?

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13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?

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18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:

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To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple

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(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.

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There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.

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4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.

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4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging

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k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:

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Sl.
No.
Voltage
(V)
Current

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(A)
Heater Temperature
(
0
C)

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Asbestos Temperature
(
0
C)
Saw dust

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Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos

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layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:

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The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)

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6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?

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11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.

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16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical

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tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which

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in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.

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The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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Schematic view of the test set-up:

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mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch

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Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples

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6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}

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Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W

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Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L
3

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?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v
2

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is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid

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v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity

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?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.

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hL / k = 0.56 (Gr.Pr)
0.25
for 10
4
< Gr.Pr.<10

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8

hL / k = 0.13 (Gr.Pr)
1/3
for 10

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8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).

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3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:

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The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m

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2
K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing

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heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?

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5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)

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10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness

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15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?

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20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:

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To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer

Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air

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stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of

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orifice meter and the water manometer fitted on the board.


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Tabulations:

Sl. No. Voltage Current Temperature in (

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0
C)
Manometer
reading of water
in h in meter

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(V) (A)
T1

T2

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T3

T4

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T5

T6

h1

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cm
h2
cm

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor

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5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0
C

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(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:

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1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.

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6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.

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2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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Formulae used:
1. The rate at which air is getting heated is calculated as

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qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o

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C)
= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate

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Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m
3
/hr

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3. ha = qa /A(Ts- Ta) W / m
2
K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m

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2

Ta = Average temperature of air = (T1 + T6)/2
o
C

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Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C
Cd = 0.64
H = Difference of water level in manometer m

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?w Density of water = 1000 Kg/m
3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

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d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

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using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2

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)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o
C

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5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

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Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k

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? = Viscosity Ns/m
2

k = Thermal conductivity of fluid W/m
2

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K
Nu = 0.023 (Re)
0.8
(Pr)
0.4

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Bulk mean temperature = (T1 + T6)/2

Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.

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hactual = -------------- W/m
2
K
htheoritical = -------------- W/m
2

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K

Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?

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3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?

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8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection

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13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

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Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

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Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,

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the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure

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temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat

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flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm

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2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.

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2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

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plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature

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gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:

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Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R

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Tabulation:
Sl.No. Voltmeter
reading
(V)
Ammeter

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reading
(A)
T1
(
0

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C)
T2
(
0
C)

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T3
(
0
C)
T4

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(
0
C)
T5
(

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0
C)
T6
(
0

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C)
T7
(
0
C)

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T8
(
0
C)

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Composite wall apparatus set-up

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Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W

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c. Asbestos section = ------------W

Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure

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Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?

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5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.

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9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

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33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

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DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

Aim:
To find out the thermal conductivity of insulating powder by conduction

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Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A

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multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

Procedure:

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1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.

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5. Repeat the experiments for different power inputs.


The readings are tabulated below

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Sl.No. Voltmeter
reading( V)
Ammeter
reading (A)
T1

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(
0
C)
T2
(

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0
C)
T3
(
0

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C)
T4
(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm

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The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Fig. 1 Apparatus of thermal conductivity of insulating powder

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[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

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Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam

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boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity

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3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.

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8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?

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13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?

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18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

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HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

Aim:

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To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is

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measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:
Sl.

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No.
V I

Fin Temperatures (
0

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C)
Ambient Temp
(
0
C)

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Manometer
Reading
(V)

(A)

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T1 T2 T3 T4 T5 T6 T7 T8
h1
cm
h2

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cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Duct size = 150 mm x 100 mm.

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2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

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Schematic view of the test set-up:



zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5

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10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C
12. Temperature indicator = 0 ? 300

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0
C
(With compensation of ambient temperature up-to 50
0
C)

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13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8

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Brass Pin Fin
Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.

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4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:

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Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.

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4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2

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Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m

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3
/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m

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3

?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s

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2

Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s

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Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

A = area of the duct

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4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.

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(T1 + T6) / 2
o
C
5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number

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6. Nusselt Number:
Nu = CRe
m
(Pr)
0.33

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7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk
m= ?(hp/kA)

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A = area of fin = (? x D
2
) /4
L = Length of the fin
Tw ? average temperature

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T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________

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Heat transfer, Q = ___________ W

Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.


40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer

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6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?

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11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.8

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DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

Aim:

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To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch

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(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water

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between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.

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When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere

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3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg

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8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C
= (or) 0.1 Kcal / kg
0

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C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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11. Temperature indicator digital 0.1
0
C L.C 0 - 200
0

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C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water
Precautions:

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Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4

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? Td
4
)
Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)

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Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

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43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulations:
Proc
edur

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e:
1. H
eat the
water
in the

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tank by
the immersion heater up to a temperature of about 90
0
C.
2. Remove the disc, D before pouring the hot water in the jacket.

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3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.

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6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m

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2
k
4
.

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Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using

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boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

Sl. No.

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Hemisphere Temperature(
0
C) Avg. Temp.
of the
Hemisphere

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(Th)
T4
Steady
Temp. of
Disc

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T0 (Td)
Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number
5. State Wien?s displacement law.

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6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation
10. What are the various modes of condensation?

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11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.9

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DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

Aim:

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To measure emissivity of the test plate surface at various temperature
Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The

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temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.
Specifications:
1. Heater input to black plate W1 = V1 x I1 W

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2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V

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6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300

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0
C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.

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Tabulation:
Sl.
No
Voltage

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Current

Black body
temp(
0

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C)
Avg.
temp.

Polished body

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temp (
0
C)
Avg.
temp.

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Enclosure
Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts

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4
? Ta
4
) A
Eb ? E = (W1 ? W2) / ? (Ts

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4
? Ta
4
) A
E = Eb ? {(W1 ? W2) / ? (Ts

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4
? Ta
4
) A}
Where,

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W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd
2
m

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2

T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)

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Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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? = Stefan boltzman constant = 5.67 x 10
-8
W/m
2
K

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4


Schematic view of the test set-up:

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Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by

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the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

Results:

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The emissivity of the test plate surface is found to be _____________.
Outcome:
From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

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48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Emissivity
2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?

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4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?
6. What is meant by shape factor?
7. Define ? Radiation
8. What is meant by monochromatic emissive power?

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9. Define ? Emissive Power
10. What is meant by absorptivity?
11. Define ? Black Body
12. What is meant by transmissivity?
13. State Plank's distribution law

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14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

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49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.10

EFFECTIVENESS OF PARALLEL / COUNTER

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FLOW HEAT EXCHANGE

Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:

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(i) Experimental Setup
(ii) Stop watch
(iii) Thermometer
Theory:
Heat exchangers are classified in three categories:

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1. Transfer type
2. Storage type
3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.

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The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water

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which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:

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1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50

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0
C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100
0
C - 2 Nos.

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7. Measuring flask = 0 ? 1000 CC

50 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

8. Geyser: single phase type to obtain hot water supply

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9. Thermo Cole insulation for outer pipe.
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Tabulations:

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Sl.
No.
Flow Hot Fluid (
0
C) Cold Fluid (

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0
C)
Time for
collection of
hot fluid

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Kg/sec
Time for
collection
of cold fluid
Kg/sec

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1 Parallel flow
Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)

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1. Area of the pipe A = ? (D ? d) L
Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube
L = Length of the tube

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2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

51 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Where, m = mass flow rate Kg/ sec.

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m = ?v/t, ? = density of water and t = time taken for hot water
Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet
Tho = Temperature of hot water outlet

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3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W
Where, m = mass flow rate
Cp = Specific heat of capacity
Tco = Temperature of cold water inlet
Tci = Temperature of cold water outlet

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4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W
Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)
?Tm = (?Ti - ?To) / In (?Ti/?To)
Where, ?To = Tho ? Tco

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?Ti = Thi ? Tci
6. Over all heat transfer coefficient
h = Q?/?Tm A W/m
2
K

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where Q? = (Qa + Qc) / 2

Procedure:
1. Place the thermometers in position and note down their readings when they are at room temperature and
no water is flowing at either side. This is required to correct the temperature.

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2. Start the flow on hot water side.
3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.
5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.
6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.

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7. Keeping the flow rates same, wait till the steady state conditions are reached.
8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.
10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

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52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Result:
1. The values of effectiveness of heat exchanger were found as

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(i) Parallel flow = ________.
(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)
(i) Parallel flow = ________.
(ii) Counter flow = _________.

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Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow
heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat
exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Heat Exchanger
2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?
4. Write about the merits of drop wise condensation.
5. What is meant by film wise and drop wise condensation?

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6. What is meant by effectiveness?
7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?
9. Distinguish between regenerator and recuperates.
10. What is meant by parallel flow heat exchanger?

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11. What is meant by counter flow heat exchanger?
12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?
Viva ? voce

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53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.11

DETERMINATION OF COP OF A REFRIGERATION

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SYSTEM

Aim:
To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration
system

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Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Experimental setup

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Description:
1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a
reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.
2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated
wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a

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low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the
temperature of chilled water. The above unit is located on the trolley behind front panel.
3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic
expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum
strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure

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gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high
pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy
meter to measure the power consumed either by hater or by compressor.

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54 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
A. A compressor condenser unit placed inside trolley and fitted with
1. R-134a reciprocating compressor
2. Condenser

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3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan
4. A receiver with angle check valve
B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity
placed inside a well insulated wooden box and provided with
5. Evaporator coil

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6. Stirrer
7. Electric heater 230 V, A.C.
8. The sensing bulb of low temperature thermostat.
9. A high temperature thermostat.
10. A Thermometer to measure the chilled water temperature

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C. The front panel on which are mounted the following
11. Capillary expansion tube with isolating valve.
12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator
and isolating valve
13. Drier cum strainer and sight glass

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14. Thermostat at inlet and outlet of both evaporator and condenser
15. Pressure gauge at inlet and outlet of evaporator and condenser
16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out
17. Heat power regulator switch and regulator
18. Energy meter to measure the power consumed either by hater or by compressor.

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55 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.
2. The heater regulator should be switched off whenever not in use. Heating water beyond 40
0
C may lead to

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permanent damage of the entire system. A high temperature cut off thermostat is provided in the water
chiller, to cut off the heater beyond 30
0
C.Check the setting of the same before operation.
3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.

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4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.
5. The solenoid thermostat is adjusted to cut at 15
0
C and cut in at 10
0

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C of the chilled water. Do not alter the
same.
6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.
7. The space near the condenser should permit good ventilation to aid proper fan performance.
8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked

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in
0
F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,
calibrated in SI units, are not available.)
9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to

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obtain the pressure in MN/m
2
.e.g. P = x psig
= (x + 14.7) psia
= (x + 14.7) / 145 MN/m

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2
(MPa)
10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.
Formulae used:
Let, State 1 indicates the entry of compressor.

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State 2 indicates the exit of compressor.
State 3 indicates the exit from condenser.
State 4 indicates the entry to evaporator
P = Pressure (bar)
T = Temperature (

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0
C)
H = Specific enthalpy (kJ/kg)
v = Specific Volume (m
3

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/Kg)
n = Number of revolutions of energy meter disc.
t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)
t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)
K = Energy meter constant = 3200 lmp / kWh

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N = Speed of compressor = 2840 rpm
h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

56 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2
h3 = Specific enthalpy at Pc and T3 (kJ/kg)
h4 = h3
Stroke volume of compressor = (?/ 4) d
2

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l = 12.58 x 10
-6
m
3

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1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar
2. Average condenser pressure, Pc = (P2 + P3) / 2 bar
3. Heater input, Qe = (n / t1) x (3600 / k) kW
4. Compressor input, W = (n / t2) x (3600 / k) kW
5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1

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6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)
7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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57 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I


Sl.

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No.

Initial
Temp.
of water

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Final
Temp.
of water
Duration

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of exp.

Delivery
pressure

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Delivery
Temp.

Condense
Outlet

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Pressure

Condense
Outlet
Temp.

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Pressure
after
throttling

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Temp.
After
Throttli
ng

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Suction
pressur
e
Suction

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Temp.

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Time for
10 rev. of
compress
or energy
meter

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Height
of water

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in the
vessel

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58 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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Load Test with Capillary tube as expansion device:
1. Fill the chilled water calorimeter with pure water so that the evaporative coils are
fully immersed.
2. Select the capillary tube line by opening the shut-off valve on this line and closing
the one on the thermostatic expansion valve line. The solenoid switch is switched OFF.

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3. Start the compressor and run for some time so that the chilled water temperature
is lowered to the given test temperature.
4. Switch on the heater and slowly increase the power.
5. Allow The temperature in water calorimeter to reach the equilibrium
temperature.

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6. Connect energy meter to motor and heater by the selector switch one after another
and note down the time taken for 10 pulses of the energy meter disc.
7. Note down the pressure and temperature readings at locations 1,2,3 & 4 as
mentioned.
8. Switch OFF the heater and the mains.

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Result:
The load test on a refrigeration test rig was conducted and the results are as follows.
1. Actual C.O.P. of the system =____________.
2. Rhetorical C.O.P. of the system = ___________.
3. Volumetric Efficiency = ___________.

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Outcome:
From this experiment, conducting the load test on a refrigeration test rig and finding out the
volumetric efficiency and co-efficient of performance for any type of refrigerant is learnt and this experiment
could be used in the areas such as Refrigerator and Air Conditioning.

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Applications:
Refrigerator, Air Conditioning.

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59 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? COP
2. Which thermodynamic cycle is used in air conditioning of airplanes using air as refrigerant?
3. Define ? Ton of Refrigeration
4. What is meant by refrigeration?
5. What is meant by air conditioning?

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6. What are the four important properties of a good refrigerant?
7. How does the actual vapour compression cycle differ from that of the ideal cycle?
8. Name any four commonly used refrigerants.
9. What are the expansion devices used in a vapour compression plant?
10. Why throttle valve is used in place of expansion cylinder for vapour compression refrigerant machine?

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11. What are the merits of air refrigeration system?
12. What are the demerits of air refrigeration system?
13. Define ? Refrigerant
14. What is net refrigerating effect of the refrigerant?
15. What are the methods to obtain sub cooling of refrigerant?

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Viva ? voce

60 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.12 EXPERIMENTS ON PSYCHROMETRIC PROCESS

Aim:
To conduct an experiment on psychrometric processes with air conditioning system
Apparatus required:

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(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Digital anemometer
(v) Experimental setup

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Description:
The test rig consist of
1. An air duct support of stand
2. A blower to set up air flow through the duct along with a speed control to vary the
velocity of air.

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3. A heater to rise the air temperature with regulator and energy meter.
4. Water spray, collecting tray, reservoir with gauge pump.
5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.
(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after cooling coil).
6. The test rig consist of compressor, condenser unit placed inside trolley and fitted

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with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for
condenser and (iv) Liquid receiver.
7. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION

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MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex

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software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills

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4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning

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To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the

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career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society

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7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with

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coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:

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HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube

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5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface

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10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes

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13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.

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4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system

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13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES

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7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6

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2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3

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Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5

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Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7

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Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS

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11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68

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15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT

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USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate

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assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The

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heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:

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1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2

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Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently

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5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm

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2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm

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7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100
0

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C
9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm

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11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A

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16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C

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19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulation:
Sl. No. Voltmeter
V
Ammeter

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A
Main heater (
0
C) Test Plate (
0

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C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.

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Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.

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4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.

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4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?

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9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?

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14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?

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19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF

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PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus

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Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter

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(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm

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5. The effective length of the above = 500 mm

14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:

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1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W

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Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material

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k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.

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No.
Voltage
(V)
Current
(A)

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Heater Temperature
(
0
C)
Asbestos Temperature

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(
0
C)
Saw dust
Temperature (

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0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.

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2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.

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6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.

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The thermal conductivity of resistive material = _________________ W /m
2
-K

Outcome:

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From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:

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Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. Define ? Nusselt Number(Nu)

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2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)

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7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?

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12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?

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17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION

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FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The

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temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold

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fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Schematic view of the test set-up:
mm

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mm

19 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.

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5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A

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7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

Tabulation:

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Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m

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2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (

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0
C) ?
2. hL / k = A { g L
3
?T Cp ?/2v

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2
}
n

Where, hL / k are called Nusselt Number.

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L
3
g?T / v
2
is called Grashof number.

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?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid

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? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta

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For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)

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0.25
for 10
4
< Gr.Pr.<10
8

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hL / k = 0.13 (Gr.Pr)
1/3
for 10
8

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< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.

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4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as

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Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m
2

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K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC

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engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?

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6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?

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11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.

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16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to

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the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

Sl. No. Voltage Current Temperature in (
0

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C)
Manometer
reading of water
in h in meter

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(V) (A)
T1

T2

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T3

T4

T5

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T6

h1
cm

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h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer

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6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0
C
(Calibrated for chromel alumel thermocouple)

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8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.

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7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat

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input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)

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Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o
C)

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= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di

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2
?2gH x (?w / ?a) m
3
/hr
3. ha = qa /A(Ts- Ta) W / m

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2
K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

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Ta = Average temperature of air = (T1 + T6)/2
o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4

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o
C
Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m

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3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

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d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

using this procedure obtain the value of ?ha? for different air flow rate

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4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2
)/4]

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v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o
C
5. Nusselt Number:

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Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

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27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m

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2

k = Thermal conductivity of fluid W/m
2
K

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Nu = 0.023 (Re)
0.8
(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

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Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m

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2
K
htheoritical = -------------- W/m
2
K

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Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?

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4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?

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9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.

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14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

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29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

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Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the

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thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The

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temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is

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the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm

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3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat

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input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

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30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.

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7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow

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R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:

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Sl.No. Voltmeter
reading
(V)
Ammeter
reading

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(A)
T1
(
0
C)

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T2
(
0
C)
T3

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(
0
C)
T4
(

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0
C)
T5
(
0

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C)
T6
(
0
C)

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T7
(
0
C)
T8

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(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Composite wall apparatus set-up

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Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

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Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal

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conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?

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10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

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33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY

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OF INSULATING POWDER

Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

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The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit

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is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

Procedure:

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1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter

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reading( V)
Ammeter
reading (A)
T1
(

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0
C)
T2
(
0

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C)
T3
(
0
C)

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T4
(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1

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Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.


34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Fig. 1 Apparatus of thermal conductivity of insulating powder

[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater

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control]

Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

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Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to

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be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?

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4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?

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9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)

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14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?

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19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

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36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

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HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:

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A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is

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shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:
Sl.
No.

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V I

Fin Temperatures (
0
C)

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Ambient Temp
(
0
C)
Manometer

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Reading
(V)

(A)

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T1 T2 T3 T4 T5 T6 T7 T8
h1
cm
h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm

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3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.

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11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C
12. Temperature indicator = 0 ? 300
0

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C
(With compensation of ambient temperature up-to 50
0
C)
13. Dimmer stat for heat input controls 230 V, 2 A

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14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8
Brass Pin Fin

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Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

16. Ammeter = 0 ? 2 A

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.

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5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:
Forced Convection:

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1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient

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temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)

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Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m
3

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/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m
3

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?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s
2

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Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

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39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

A = area of the duct
4. Reynold?s Number:

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Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2

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o
C
5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number
6. Nusselt Number:

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Nu = CRe
m
(Pr)
0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)

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h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk
m= ?(hp/kA)
A = area of fin = (? x D

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2
) /4
L = Length of the fin
Tw ? average temperature
T? ? ambient (surface) temperature (T6)

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8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

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Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through

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pin-fin is to be found.


40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Extended Surface

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2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer
6. Define ? Fin Efficiency

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7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?
11. Define ? Convection

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12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

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41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.8

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DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus

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Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Geyser water

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Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to

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measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response

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of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm

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4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg

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0
C
= (or) 0.1 Kcal / kg
0
C

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9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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11. Temperature indicator digital 0.1
0
C L.C 0 - 200
0
C with built-in cold junction compensation and a timer set

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for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically

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there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4
? Td

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4
)
Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0

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dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:
Proc
edur
e:

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1. H
eat the
water
in the
tank by

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the immersion heater up to a temperature of about 90
0
C.
2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.

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4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate

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thermocouple).

Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m
2

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k
4
.

Outcome:

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From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.

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.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

Sl. No.
Hemisphere Temperature(

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0
C) Avg. Temp.
of the
Hemisphere
(Th)

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T4
Steady
Temp. of
Disc
T0 (Td)

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Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]

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2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number
5. State Wien?s displacement law.
6. What is the significance of Biot Number?

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7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation
10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]

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12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

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45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.9

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DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

Aim:
To measure emissivity of the test plate surface at various temperature

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:

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The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp

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black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.
Specifications:
1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W

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3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A

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7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300
0

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C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Use proper voltage range on Voltmeter.

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3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.
Tabulation:

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Sl.
No
Voltage

Current

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Black body
temp(
0
C)

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Avg.
temp.

Polished body
temp (

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0
C)
Avg.
temp.

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Enclosure
Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts
4

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? Ta
4
) A
Eb ? E = (W1 ? W2) / ? (Ts
4

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? Ta
4
) A
E = Eb ? {(W1 ? W2) / ? (Ts
4

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? Ta
4
) A}
Where,
W1 = Heater input to black plate = V1 x I1 W

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W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd
2
m
2

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T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)
Eb = Emissivity of black plate = 1

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E = Emissivity of Test plate

47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

? = Stefan boltzman constant = 5.67 x 10

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-8
W/m
2
K
4

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Schematic view of the test set-up:

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Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by
the dimmer stat so that the two plates will be maintained at the same temperature.

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3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

Results:
The emissivity of the test plate surface is found to be _____________.

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Outcome:
From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

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48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Emissivity
2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?
4. State Lambert?s cosine law.

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5. What is the purpose of radiation shield?
6. What is meant by shape factor?
7. Define ? Radiation
8. What is meant by monochromatic emissive power?
9. Define ? Emissive Power

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10. What is meant by absorptivity?
11. Define ? Black Body
12. What is meant by transmissivity?
13. State Plank's distribution law
14. What is meant by gray body?

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15. Define ? Irradiation

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Viva ? voce

49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.10

EFFECTIVENESS OF PARALLEL / COUNTER
FLOW HEAT EXCHANGE

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Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:
(i) Experimental Setup

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(ii) Stop watch
(iii) Thermometer
Theory:
Heat exchangers are classified in three categories:
1. Transfer type

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2. Storage type
3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.
The transfer type exchangers are further classified accordant to flow arrangements as:

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i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water
which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water

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flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:
1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm

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2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50
0

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C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100
0
C - 2 Nos.
7. Measuring flask = 0 ? 1000 CC

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50 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

8. Geyser: single phase type to obtain hot water supply
9. Thermo Cole insulation for outer pipe.

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Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Tabulations:
Sl.

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No.
Flow Hot Fluid (
0
C) Cold Fluid (
0

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C)
Time for
collection of
hot fluid
Kg/sec

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Time for
collection
of cold fluid
Kg/sec
1 Parallel flow

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Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)
1. Area of the pipe A = ? (D ? d) L

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Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube
L = Length of the tube

2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

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51 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Where, m = mass flow rate Kg/ sec.
m = ?v/t, ? = density of water and t = time taken for hot water

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Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet
Tho = Temperature of hot water outlet

3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W

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Where, m = mass flow rate
Cp = Specific heat of capacity
Tco = Temperature of cold water inlet
Tci = Temperature of cold water outlet
4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W

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Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)
?Tm = (?Ti - ?To) / In (?Ti/?To)
Where, ?To = Tho ? Tco
?Ti = Thi ? Tci

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6. Over all heat transfer coefficient
h = Q?/?Tm A W/m
2
K
where Q? = (Qa + Qc) / 2

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Procedure:
1. Place the thermometers in position and note down their readings when they are at room temperature and
no water is flowing at either side. This is required to correct the temperature.
2. Start the flow on hot water side.

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3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.
5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.
6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.
7. Keeping the flow rates same, wait till the steady state conditions are reached.

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8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.
10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Result:
1. The values of effectiveness of heat exchanger were found as
(i) Parallel flow = ________.

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(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)
(i) Parallel flow = ________.
(ii) Counter flow = _________.

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Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow
heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat
exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.
Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.



1. Define ? Heat Exchanger

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2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?
4. Write about the merits of drop wise condensation.
5. What is meant by film wise and drop wise condensation?
6. What is meant by effectiveness?

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7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?
9. Distinguish between regenerator and recuperates.
10. What is meant by parallel flow heat exchanger?
11. What is meant by counter flow heat exchanger?

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12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?
Viva ? voce

53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.11

DETERMINATION OF COP OF A REFRIGERATION
SYSTEM

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Aim:
To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration
system
Apparatus required:

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(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Experimental setup
Description:

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1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a
reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.
2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated
wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a
low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the

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temperature of chilled water. The above unit is located on the trolley behind front panel.
3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic
expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum
strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure
gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high

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pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy
meter to measure the power consumed either by hater or by compressor.

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54 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
A. A compressor condenser unit placed inside trolley and fitted with
1. R-134a reciprocating compressor
2. Condenser
3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan

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4. A receiver with angle check valve
B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity
placed inside a well insulated wooden box and provided with
5. Evaporator coil
6. Stirrer

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7. Electric heater 230 V, A.C.
8. The sensing bulb of low temperature thermostat.
9. A high temperature thermostat.
10. A Thermometer to measure the chilled water temperature
C. The front panel on which are mounted the following

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11. Capillary expansion tube with isolating valve.
12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator
and isolating valve
13. Drier cum strainer and sight glass
14. Thermostat at inlet and outlet of both evaporator and condenser

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15. Pressure gauge at inlet and outlet of evaporator and condenser
16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out
17. Heat power regulator switch and regulator
18. Energy meter to measure the power consumed either by hater or by compressor.

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55 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:

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1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.
2. The heater regulator should be switched off whenever not in use. Heating water beyond 40
0
C may lead to
permanent damage of the entire system. A high temperature cut off thermostat is provided in the water

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chiller, to cut off the heater beyond 30
0
C.Check the setting of the same before operation.
3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.
4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.

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5. The solenoid thermostat is adjusted to cut at 15
0
C and cut in at 10
0
C of the chilled water. Do not alter the

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same.
6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.
7. The space near the condenser should permit good ventilation to aid proper fan performance.
8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked
in

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0
F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,
calibrated in SI units, are not available.)
9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to
obtain the pressure in MN/m

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2
.e.g. P = x psig
= (x + 14.7) psia
= (x + 14.7) / 145 MN/m
2

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(MPa)
10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.
Formulae used:
Let, State 1 indicates the entry of compressor.
State 2 indicates the exit of compressor.

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State 3 indicates the exit from condenser.
State 4 indicates the entry to evaporator
P = Pressure (bar)
T = Temperature (
0

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C)
H = Specific enthalpy (kJ/kg)
v = Specific Volume (m
3
/Kg)

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n = Number of revolutions of energy meter disc.
t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)
t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)
K = Energy meter constant = 3200 lmp / kWh
N = Speed of compressor = 2840 rpm

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h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

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h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2

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h3 = Specific enthalpy at Pc and T3 (kJ/kg)
h4 = h3
Stroke volume of compressor = (?/ 4) d
2
l = 12.58 x 10

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-6
m
3

1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar

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2. Average condenser pressure, Pc = (P2 + P3) / 2 bar
3. Heater input, Qe = (n / t1) x (3600 / k) kW
4. Compressor input, W = (n / t2) x (3600 / k) kW
5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1
6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)

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7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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57 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I


Sl.
No.

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Initial
Temp.
of water

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Final
Temp.
of water
Duration
of exp.

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Delivery
pressure

Delivery

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Temp.

Condense
Outlet
Pressure

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Condense
Outlet
Temp.

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Pressure
after
throttling

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Temp.

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After
Throttli
ng

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Suction
pressur
e
Suction
Temp.

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Time for

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10 rev. of
compress
or energy
meter

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Height
of water
in the

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vessel

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58 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
Load Test with Capillary tube as expansion device:

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1. Fill the chilled water calorimeter with pure water so that the evaporative coils are
fully immersed.
2. Select the capillary tube line by opening the shut-off valve on this line and closing
the one on the thermostatic expansion valve line. The solenoid switch is switched OFF.
3. Start the compressor and run for some time so that the chilled water temperature

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is lowered to the given test temperature.
4. Switch on the heater and slowly increase the power.
5. Allow The temperature in water calorimeter to reach the equilibrium
temperature.
6. Connect energy meter to motor and heater by the selector switch one after another

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and note down the time taken for 10 pulses of the energy meter disc.
7. Note down the pressure and temperature readings at locations 1,2,3 & 4 as
mentioned.
8. Switch OFF the heater and the mains.
Result:

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The load test on a refrigeration test rig was conducted and the results are as follows.
1. Actual C.O.P. of the system =____________.
2. Rhetorical C.O.P. of the system = ___________.
3. Volumetric Efficiency = ___________.

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Outcome:
From this experiment, conducting the load test on a refrigeration test rig and finding out the
volumetric efficiency and co-efficient of performance for any type of refrigerant is learnt and this experiment
could be used in the areas such as Refrigerator and Air Conditioning.
Applications:

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Refrigerator, Air Conditioning.

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59 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? COP

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2. Which thermodynamic cycle is used in air conditioning of airplanes using air as refrigerant?
3. Define ? Ton of Refrigeration
4. What is meant by refrigeration?
5. What is meant by air conditioning?
6. What are the four important properties of a good refrigerant?

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7. How does the actual vapour compression cycle differ from that of the ideal cycle?
8. Name any four commonly used refrigerants.
9. What are the expansion devices used in a vapour compression plant?
10. Why throttle valve is used in place of expansion cylinder for vapour compression refrigerant machine?
11. What are the merits of air refrigeration system?

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12. What are the demerits of air refrigeration system?
13. Define ? Refrigerant
14. What is net refrigerating effect of the refrigerant?
15. What are the methods to obtain sub cooling of refrigerant?

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Viva ? voce

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60 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.12 EXPERIMENTS ON PSYCHROMETRIC PROCESS

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Aim:
To conduct an experiment on psychrometric processes with air conditioning system
Apparatus required:
(i) Thermometer

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(ii) Electric Heater
(iii) Stop watch
(iv) Digital anemometer
(v) Experimental setup
Description:

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The test rig consist of
1. An air duct support of stand
2. A blower to set up air flow through the duct along with a speed control to vary the
velocity of air.
3. A heater to rise the air temperature with regulator and energy meter.

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4. Water spray, collecting tray, reservoir with gauge pump.
5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.
(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after cooling coil).
6. The test rig consist of compressor, condenser unit placed inside trolley and fitted
with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for

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condenser and (iv) Liquid receiver.
7. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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61 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I

Precautions:
1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence
avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kw only for the motor

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circuit.
2. Natural air currents in the room if in the direction of air duct may defect the experimental results and
hence the duct should be placed such that no wind from doors, windows, fan and cooling air from
other test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan
and should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase

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beyond 240 psi.
3. Never exceed dry bulb temperatures of 40
0
C after the heater (station 2) otherwise the air duct may be
damaged.

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4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may
exceed its maximum of 32
0
C and calibration may be affected.
5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not

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running this will lead to rise in temperature at the heater and may damage the heater and the air duct.
6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their
duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.
7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer
is placed inside the reservoir at the top. This may have to the cleaned when necessary.

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8. Do not open the gate valve fully otherwise water may be splashed outside and the waster
measurement may be in error.
S.
N
o

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Inlet temp
Outlet
temp
Pressu
re

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P1
Tem
p.
T1
Pressu

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re
P2
Temp.
T2
Pressu

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re
P3

Tem
p.

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T3


Pressu
re

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P4


Temp.
T4

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Energy
for 10
revolutio
ns
Twet Tdry Twet Tdry Lb/in

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o
C Lb/in
o
C Lb/in
o

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C Lb/in
o
C

FirstRanker.com - FirstRanker's Choice

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1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL

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2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels

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? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

--- Content provided by FirstRanker.com ---

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VISION

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MISSION
VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals

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2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which

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enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt

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and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able

--- Content provided by FirstRanker.com ---

1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution

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5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both

--- Content provided by FirstRanker.com ---

verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus

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3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)

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8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:

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11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus

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3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction

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7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-

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efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.

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15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.

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CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus

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11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15

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4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6

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Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43

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10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63

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14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75

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PROJECT WORK 81

8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:

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To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in

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which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.

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Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d

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2
(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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9 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.

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4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

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Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm

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5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0

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C ? 100
0
C
9. Maximum temperature of the hot plate = 170
0

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C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V

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14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200

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0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:
Sl. No. Voltmeter

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V
Ammeter
A
Main heater (
0

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C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.

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3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.

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7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be

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k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat

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exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity

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2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?

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7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.

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12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.

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17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

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Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus

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(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is

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transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside

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an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm

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3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.

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3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)

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Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found

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Tabulation:
Sl.
No.
Voltage
(V)

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Current
(A)
Heater Temperature
(
0

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C)
Asbestos Temperature
(
0
C)

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Saw dust
Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.

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5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.

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Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?

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5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?

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10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow

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15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.

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20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:

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To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of

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the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

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When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Schematic view of the test set-up:
mm
mm

19 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm

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4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel

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thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0

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c)

V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Heat transfer coefficient is given by

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h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m

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2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C

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q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L

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3
?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v

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2
is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface

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K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid

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G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K

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-1

Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been

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determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25
for 10
4

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< Gr.Pr.<10
8

hL / k = 0.13 (Gr.Pr)
1/3

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for 10
8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.

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2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

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Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K

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Experimental = ______________ W/ m
2
K

Outcomes:

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From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.

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4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.

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9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?

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14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness

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19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

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Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer

Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band

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heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to

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measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.


24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

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Sl. No. Voltage Current Temperature in (
0
C)
Manometer
reading of water

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in h in meter

(V) (A)
T1

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T2

T3

T4

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T5

T6

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h1
cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm

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4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0

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C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.

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5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference

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in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.

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4. Note down the heater input.

26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:

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1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (

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o
C)
= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr

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Q = Volume flow rate
Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m
3

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/hr
3. ha = qa /A(Ts- Ta) W / m
2
K
qa = Rate of which air is getting heated.

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A = Test section area = ? x Di x L m
2

Ta = Average temperature of air = (T1 + T6)/2
o

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C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C
Cd = 0.64

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H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m

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3

d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

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using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di

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2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o

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C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings

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6. Prandtl Number:

27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k

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Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

k = Thermal conductivity of fluid W/m

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2
K
Nu = 0.023 (Re)
0.8
(Pr)

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0.4
Bulk mean temperature = (T1 + T6)/2

Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection

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apparatus.
hactual = -------------- W/m
2
K
htheoritical = -------------- W/m

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2
K

Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection

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apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is meant by boiling and condensation?

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2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?

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7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?

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12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:

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When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly

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temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The

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apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:

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1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:

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1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.

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5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)

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6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.

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Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities

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Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter
reading
(V)

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Ammeter
reading
(A)
T1
(

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0
C)
T2
(
0

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C)
T3
(
0
C)

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T4
(
0
C)
T5

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(
0
C)
T6
(

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0
C)
T7
(
0

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C)
T8
(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W

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b. Wood section = ---------------W
c. Asbestos section = ------------W

Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt

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and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.

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4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.

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8. Explain the significance of Fourier number.
9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

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DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

Aim:

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To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and

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T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

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Procedure:

1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.

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4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.


The readings are tabulated below

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Sl.No. Voltmeter
reading( V)
Ammeter
reading (A)

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T1
(
0
C)
T2

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(
0
C)
T3
(

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0
C)
T4
(
0

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C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm

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The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Fig. 1 Apparatus of thermal conductivity of insulating powder

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[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

Result:

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The thermal conductivity of insulating powder by conduction is found and the result is, ___________

Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is

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analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is the need for conducting this experiment?

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2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.

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7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?

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12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?

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17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.7

HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

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Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer
Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the

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fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:

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Sl.
No.
V I

Fin Temperatures (

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0
C)
Ambient Temp
(
0

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C)
Manometer
Reading
(V)

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(A)

T1 T2 T3 T4 T5 T6 T7 T8
h1
cm

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h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

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Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor

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9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C

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12. Temperature indicator = 0 ? 300
0
C
(With compensation of ambient temperature up-to 50
0

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C)
13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1

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T8
Brass Pin Fin
Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.

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3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.

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Procedure:
Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.

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3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)

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1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2

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) /4}?2gha m
3
/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m

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?w Density of water = 1000 kg/m
3

?a = Density of air = 1.165 kg/m
3

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g = acceleration due to gravity = 9.81 m/s
2

Cd = Coefficient of discharge = 0.64
D = diameter of the orifice

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3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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A = area of the duct
4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin

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v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2
o
C
5. Heat transfer coefficient, h = Nu k / D

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Where Nu = Nusselt Number
6. Nusselt Number:
Nu = CRe
m
(Pr)

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0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk

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m= ?(hp/kA)
A = area of fin = (? x D
2
) /4
L = Length of the fin

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Tw ? average temperature
T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were

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Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced

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convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.

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40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?

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5. Define ? Heat Transfer
6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?

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10. What is meant by steady state heat conduction?
11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number

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15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.8

DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

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Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer
(ii) Electric Heater

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(iii) Stop watch
(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.

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The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on

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the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm

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2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm

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7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C
= (or) 0.1 Kcal / kg

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0
C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

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11. Temperature indicator digital 0.1
0
C L.C 0 - 200

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0
C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water

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Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th

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4
? Td
4
)
Where, A = area of the disc

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Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

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43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulations:
Proc

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edur
e:
1. H
eat the
water

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in the
tank by
the immersion heater up to a temperature of about 90
0
C.

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2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.

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5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

Result:

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The Stefan Boltzman constant was found out to be = _______________________ m/m
2
k
4
.

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Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,

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Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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Sl. No.
Hemisphere Temperature(
0
C) Avg. Temp.
of the

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Hemisphere
(Th)
T4
Steady
Temp. of

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Disc
T0 (Td)
Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number

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5. State Wien?s displacement law.
6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation

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10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?

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15. Explain the concept of black body.

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Viva ? voce

45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.9

DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

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Aim:
To measure emissivity of the test plate surface at various temperature
Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer
Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats

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and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.
Specifications:

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1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each

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5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.

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10. Temperature Indicator = 0 ? 300
0
C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:

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1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.

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6. See that the black plate is having a layer of lamp black uniformly.
Tabulation:
Sl.
No
Voltage

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Current

Black body
temp(

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0
C)
Avg.
temp.

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Polished body
temp (
0
C)
Avg.

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temp.

Enclosure
Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,

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W1 ? W2 = (Eb ? E) ? (Ts
4
? Ta
4
) A

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Eb ? E = (W1 ? W2) / ? (Ts
4
? Ta
4
) A

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E = Eb ? {(W1 ? W2) / ? (Ts
4
? Ta
4
) A}

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Where,
W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd
2

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m
2

T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure

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Ts = surface temperature of the discs (or T1)
Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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? = Stefan boltzman constant = 5.67 x 10
-8
W/m
2

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K
4


Schematic view of the test set-up:

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Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,

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2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by
the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

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Results:
The emissivity of the test plate surface is found to be _____________.
Outcome:
From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Emissivity
2. State Kirchoff?s law of radiation.

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3. What is meant by reflectivity?
4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?
6. What is meant by shape factor?
7. Define ? Radiation

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8. What is meant by monochromatic emissive power?
9. Define ? Emissive Power
10. What is meant by absorptivity?
11. Define ? Black Body
12. What is meant by transmissivity?

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13. State Plank's distribution law
14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

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49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.10

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EFFECTIVENESS OF PARALLEL / COUNTER
FLOW HEAT EXCHANGE

Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow

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Apparatus required:
(i) Experimental Setup
(ii) Stop watch
(iii) Thermometer
Theory:

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Heat exchangers are classified in three categories:
1. Transfer type
2. Storage type
3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is

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transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.
The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.

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The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water
which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.

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Specifications:
1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm

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5. Thermometers (for cold water) = 0 ? 50
0
C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100
0

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C - 2 Nos.
7. Measuring flask = 0 ? 1000 CC

50 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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8. Geyser: single phase type to obtain hot water supply
9. Thermo Cole insulation for outer pipe.
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.

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Tabulations:
Sl.
No.
Flow Hot Fluid (
0

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C) Cold Fluid (
0
C)
Time for
collection of

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hot fluid
Kg/sec
Time for
collection
of cold fluid

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Kg/sec
1 Parallel flow
Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)
1. Area of the pipe A = ? (D ? d) L
Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube
L = Length of the tube

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2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

51 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Where, m = mass flow rate Kg/ sec.
m = ?v/t, ? = density of water and t = time taken for hot water
Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet
Tho = Temperature of hot water outlet

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3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W
Where, m = mass flow rate
Cp = Specific heat of capacity
Tco = Temperature of cold water inlet

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Tci = Temperature of cold water outlet
4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W
Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)
?Tm = (?Ti - ?To) / In (?Ti/?To)

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Where, ?To = Tho ? Tco
?Ti = Thi ? Tci
6. Over all heat transfer coefficient
h = Q?/?Tm A W/m
2

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K
where Q? = (Qa + Qc) / 2

Procedure:
1. Place the thermometers in position and note down their readings when they are at room temperature and

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no water is flowing at either side. This is required to correct the temperature.
2. Start the flow on hot water side.
3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.
5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.

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6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.
7. Keeping the flow rates same, wait till the steady state conditions are reached.
8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.
10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

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52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Result:

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1. The values of effectiveness of heat exchanger were found as
(i) Parallel flow = ________.
(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)
(i) Parallel flow = ________.

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(ii) Counter flow = _________.

Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow
heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat

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exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Heat Exchanger
2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?
4. Write about the merits of drop wise condensation.

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5. What is meant by film wise and drop wise condensation?
6. What is meant by effectiveness?
7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?
9. Distinguish between regenerator and recuperates.

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10. What is meant by parallel flow heat exchanger?
11. What is meant by counter flow heat exchanger?
12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?
Viva ? voce

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53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.11

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DETERMINATION OF COP OF A REFRIGERATION
SYSTEM

Aim:
To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration

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system
Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch

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(iv) Experimental setup
Description:
1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a
reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.
2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated

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wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a
low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the
temperature of chilled water. The above unit is located on the trolley behind front panel.
3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic
expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum

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strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure
gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high
pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy
meter to measure the power consumed either by hater or by compressor.

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54 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
A. A compressor condenser unit placed inside trolley and fitted with
1. R-134a reciprocating compressor

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2. Condenser
3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan
4. A receiver with angle check valve
B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity
placed inside a well insulated wooden box and provided with

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5. Evaporator coil
6. Stirrer
7. Electric heater 230 V, A.C.
8. The sensing bulb of low temperature thermostat.
9. A high temperature thermostat.

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10. A Thermometer to measure the chilled water temperature
C. The front panel on which are mounted the following
11. Capillary expansion tube with isolating valve.
12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator
and isolating valve

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13. Drier cum strainer and sight glass
14. Thermostat at inlet and outlet of both evaporator and condenser
15. Pressure gauge at inlet and outlet of evaporator and condenser
16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out
17. Heat power regulator switch and regulator

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18. Energy meter to measure the power consumed either by hater or by compressor.



55 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.
2. The heater regulator should be switched off whenever not in use. Heating water beyond 40
0

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C may lead to
permanent damage of the entire system. A high temperature cut off thermostat is provided in the water
chiller, to cut off the heater beyond 30
0
C.Check the setting of the same before operation.

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3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.
4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.
5. The solenoid thermostat is adjusted to cut at 15
0
C and cut in at 10

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0
C of the chilled water. Do not alter the
same.
6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.
7. The space near the condenser should permit good ventilation to aid proper fan performance.

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8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked
in
0
F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,
calibrated in SI units, are not available.)

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9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to
obtain the pressure in MN/m
2
.e.g. P = x psig
= (x + 14.7) psia

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= (x + 14.7) / 145 MN/m
2
(MPa)
10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.
Formulae used:

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Let, State 1 indicates the entry of compressor.
State 2 indicates the exit of compressor.
State 3 indicates the exit from condenser.
State 4 indicates the entry to evaporator
P = Pressure (bar)

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T = Temperature (
0
C)
H = Specific enthalpy (kJ/kg)
v = Specific Volume (m

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3
/Kg)
n = Number of revolutions of energy meter disc.
t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)
t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)

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K = Energy meter constant = 3200 lmp / kWh
N = Speed of compressor = 2840 rpm
h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

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h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2
h3 = Specific enthalpy at Pc and T3 (kJ/kg)
h4 = h3
Stroke volume of compressor = (?/ 4) d

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2
l = 12.58 x 10
-6
m
3

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1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar
2. Average condenser pressure, Pc = (P2 + P3) / 2 bar
3. Heater input, Qe = (n / t1) x (3600 / k) kW
4. Compressor input, W = (n / t2) x (3600 / k) kW

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5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1
6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)
7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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57 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

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Sl.
No.

Initial
Temp.

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of water

Final
Temp.
of water

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Duration
of exp.

Delivery
pressure

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Delivery
Temp.

Condense

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Outlet
Pressure

Condense
Outlet

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Temp.


Pressure
after

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throttling

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Temp.
After
Throttli
ng

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Suction
pressur
e

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Suction
Temp.

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Time for
10 rev. of
compress
or energy

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meter



Height

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of water
in the
vessel

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58 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
Load Test with Capillary tube as expansion device:
1. Fill the chilled water calorimeter with pure water so that the evaporative coils are
fully immersed.
2. Select the capillary tube line by opening the shut-off valve on this line and closing

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the one on the thermostatic expansion valve line. The solenoid switch is switched OFF.
3. Start the compressor and run for some time so that the chilled water temperature
is lowered to the given test temperature.
4. Switch on the heater and slowly increase the power.
5. Allow The temperature in water calorimeter to reach the equilibrium

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temperature.
6. Connect energy meter to motor and heater by the selector switch one after another
and note down the time taken for 10 pulses of the energy meter disc.
7. Note down the pressure and temperature readings at locations 1,2,3 & 4 as
mentioned.

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8. Switch OFF the heater and the mains.
Result:
The load test on a refrigeration test rig was conducted and the results are as follows.
1. Actual C.O.P. of the system =____________.
2. Rhetorical C.O.P. of the system = ___________.

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3. Volumetric Efficiency = ___________.

Outcome:
From this experiment, conducting the load test on a refrigeration test rig and finding out the
volumetric efficiency and co-efficient of performance for any type of refrigerant is learnt and this experiment

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could be used in the areas such as Refrigerator and Air Conditioning.
Applications:
Refrigerator, Air Conditioning.

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59 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? COP
2. Which thermodynamic cycle is used in air conditioning of airplanes using air as refrigerant?
3. Define ? Ton of Refrigeration
4. What is meant by refrigeration?

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5. What is meant by air conditioning?
6. What are the four important properties of a good refrigerant?
7. How does the actual vapour compression cycle differ from that of the ideal cycle?
8. Name any four commonly used refrigerants.
9. What are the expansion devices used in a vapour compression plant?

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10. Why throttle valve is used in place of expansion cylinder for vapour compression refrigerant machine?
11. What are the merits of air refrigeration system?
12. What are the demerits of air refrigeration system?
13. Define ? Refrigerant
14. What is net refrigerating effect of the refrigerant?

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15. What are the methods to obtain sub cooling of refrigerant?

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Viva ? voce

60 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.12 EXPERIMENTS ON PSYCHROMETRIC PROCESS

Aim:
To conduct an experiment on psychrometric processes with air conditioning system

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Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Digital anemometer

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(v) Experimental setup
Description:
The test rig consist of
1. An air duct support of stand
2. A blower to set up air flow through the duct along with a speed control to vary the

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velocity of air.
3. A heater to rise the air temperature with regulator and energy meter.
4. Water spray, collecting tray, reservoir with gauge pump.
5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.
(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after cooling coil).

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6. The test rig consist of compressor, condenser unit placed inside trolley and fitted
with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for
condenser and (iv) Liquid receiver.
7. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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61 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I

Precautions:

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1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence
avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kw only for the motor
circuit.
2. Natural air currents in the room if in the direction of air duct may defect the experimental results and
hence the duct should be placed such that no wind from doors, windows, fan and cooling air from

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other test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan
and should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase
beyond 240 psi.
3. Never exceed dry bulb temperatures of 40
0

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C after the heater (station 2) otherwise the air duct may be
damaged.
4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may
exceed its maximum of 32
0

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C and calibration may be affected.
5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not
running this will lead to rise in temperature at the heater and may damage the heater and the air duct.
6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their
duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.

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7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer
is placed inside the reservoir at the top. This may have to the cleaned when necessary.
8. Do not open the gate valve fully otherwise water may be splashed outside and the waster
measurement may be in error.
S.

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N
o
Inlet temp
Outlet
temp

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Pressu
re
P1
Tem
p.

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T1
Pressu
re
P2
Temp.

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T2
Pressu
re
P3

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Tem
p.
T3

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Pressu
re
P4

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Temp.
T4
Energy
for 10
revolutio

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ns
Twet Tdry Twet Tdry Lb/in
o
C Lb/in
o

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C Lb/in
o
C Lb/in
o
C

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9. If the low pressure cut out comes in to action, it means that the Freon charge is insufficient and may

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have to be filled up. The suction pressure should never go below 2 psi as otherwise the compressor
seals will be damaged and air and moisture may enter the system.
10. The refrigerant strainer placed on the front panel should always be warm. If it cools and moisture
condenser on it, then the strainer might have to be charged by an experienced refrigeration
mechanics.

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11. The refrigerating system can work continuously for 2 hours, however if the room temperature is above
25
0
C the condenser may be heated up and the delivery pressure may rise. Do not exceed 240 psi.
Pour one or two glasses of drinking water over the fins of the condenser in order to reduce the

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delivery pressure.
12. After some months of operation the compressor may have to be topped up with oil and some quantity
of Freon-22 may have to be charged by an experienced mechanics.
13. See that distilled water is filled up in the plastic dishes provided under the wet bulb thermometers and
that the wicks are in tact otherwise erroneous readings may be obtained. These thermometers will

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show correct readings only when the fan is in operation.
14. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

Formulae used:

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1. Corresponding to the dry and wet bulb temperature at all the stations obtain the specific enthalpy and
specific humidity values from psychrometric chart.
i.e., h1 and w1 at tb1 and tw1 and so on.
2. Air flow rate, ma = (A x V) / v4 Kg / sec
Where, A = Area of duct at outlet in m

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2
(0.46 m x 0.086 m)
V = Air velocity ( m / sec)
V4 = Specific volume of moist air at station 4 using psychometric chart m
3

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/Kg
3. Moisture added from psychrometric chart, mw1 = ma (w3-w2) Kg / sec.
Where, w3 = Specific humidity at station 3
w2 = Specific humidity at station 2
4. Cooling effect produced on air, Qe = ma (h3 ? h4) kW.

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Where, h3 = Specific enthalpy at state 3 kJ/kg
h4 = Specific enthalpy at state 4 kJ/kg
5. Moisture condensed, mcl = ma (w3 ? w4) kg/sec
Where, w3 = Specific humidity at station 3
w4 = Specific humidity at station 4

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FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________

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Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and

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enterprising professionals conforming to global standards through value based quality education and training.



? To provide competent technical manpower capable of meeting requirements of the industry

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? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING



Rendering the services to the global needs of engineering industries by educating students to become

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professionally sound mechanical engineers of excellent caliber



To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on

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experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION
MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould

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them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth

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To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up

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their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME OUTCOMES (POs)

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On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications

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4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability

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8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills

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11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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ME6512 ? THERMAL ENGINEERING LABORATORY ? II



? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the

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performance of refrigeration cycle / components

LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus

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2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder

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7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

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REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System

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15. Performance test in a fluidized Bed Cooling Tower



1. Able to find out the thermal conductivity of various materials.

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2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials

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6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.

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11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures

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14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
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CONTENTS


Sl.No.
Name of the experiment

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Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe

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apparatus
11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder

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15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS

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6
Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39

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9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58

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13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS

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16 Air conditioning test rig 75
PROJECT WORK 81

8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

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Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup

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(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to

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prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater

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assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved

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aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK

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3. Area, A = ( ?/4) d
2
(10 + x)

cm

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2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.

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2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there

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is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

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Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm

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4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40

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0
C ? 100
0
C
9. Maximum temperature of the hot plate = 170

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0
C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)

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13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)

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18. Temperature indicator = 0 ? 200
0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm

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21. Specimen used = Press wood

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Tabulation:

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Sl. No. Voltmeter
V
Ammeter
A
Main heater (

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0
C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water

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is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from

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thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably

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steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:

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Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded

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hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.

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6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer

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11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?

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16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

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Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup

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(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter
Theory:

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The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in

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the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:
1. Diameter of the heater Rod = 20 mm.

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2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).

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2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by

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Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging

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material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.
No.
Voltage

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(V)
Current
(A)
Heater Temperature
(

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0
C)
Asbestos Temperature
(
0

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C)
Saw dust
Temperature (
0
C)

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T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.

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4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.

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7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2

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-K

Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC

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engines, heat exchangers, etc. where heat transfer is to be found.

Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?

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4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?

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9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?

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14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis

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19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

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Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:
(i) Experimental setup

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(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at

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the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

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When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Schematic view of the test set-up:
mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm

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3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0

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C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V

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9. Heater = Cartridge type (400 W)

Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (

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0
c)

V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:

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1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2
K

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As = Area of heat transfer surface = ? x d x l m
2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0

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C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0
C) ?

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2. hL / k = A { g L
3
?T Cp ?/2v
2
}

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n

Where, hL / k are called Nusselt Number.
L
3

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g?T / v
2
is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.

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Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid

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? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0

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K
-1

Where Tf = (Ts + Ta )/ 2

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For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25
for 10

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4
< Gr.Pr.<10
8

hL / k = 0.13 (Gr.Pr)

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1/3
for 10
8
< Gr.Pr.<10
12

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Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

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Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2

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K
Experimental = ______________ W/ m
2
K

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Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?

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3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?

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8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer

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13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.

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18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No. 4

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

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Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:

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(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

Theory:

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Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat

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supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



Tabulations:

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Sl. No. Voltage Current Temperature in (
0
C)
Manometer

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reading of water
in h in meter

(V) (A)
T1

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T2

T3

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T4

T5

T6

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h1
cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm

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3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300

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0
C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A

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10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.

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4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:

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1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady

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state is reached.
4. Note down the heater input.

26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)

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?T = Temperature rise in air (
o
C)
= T6 ? T1.
2. m = Q?

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Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m

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3
/hr
3. ha = qa /A(Ts- Ta) W / m
2
K

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qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

Ta = Average temperature of air = (T1 + T6)/2

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o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C

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Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

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?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s

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2

using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number

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Where, V = velocity of air = Q/[(? x Di
2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2

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o
C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K

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Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

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k = Thermal conductivity of fluid W/m
2
K
Nu = 0.023 (Re)
0.8

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(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

Results:

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Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m
2
K

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htheoritical = -------------- W/m
2
K

Outcome:

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From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.

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6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?

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11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall

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Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The

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temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus

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uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.

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Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.

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Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.

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4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from

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the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate

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Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter
reading

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(V)
Ammeter
reading
(A)
T1

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(
0
C)
T2
(

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0
C)
T3
(
0

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C)
T4
(
0
C)

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T5
(
0
C)
T6

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(
0
C)
T7
(

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0
C)
T8
(
0

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C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:
The rate of heat transfer through different materials are found to be

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a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

Outcome:

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From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.



32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?

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3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.

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7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?

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12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

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Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between

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the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

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Procedure:

1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.

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3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter
reading( V)
Ammeter

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reading (A)
T1
(
0
C)

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T2
(
0
C)
T3

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(
0
C)
T4
(

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0
C)

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Calculations:

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The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Fig. 1 Apparatus of thermal conductivity of insulating powder

[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

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Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

Outcome:

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From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?

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6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?

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11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection

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16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.7

HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

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Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer
Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of

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the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:

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Forced convection:
Sl.
No.
V I

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Fin Temperatures (
0
C)
Ambient Temp
(

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0
C)
Manometer
Reading
(V)

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(A)

T1 T2 T3 T4 T5 T6 T7 T8
h1

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cm
h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm

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5. Diameter of the delivery pipe (O.D) = 46 mm

Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64

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8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0

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C
12. Temperature indicator = 0 ? 300
0
C
(With compensation of ambient temperature up-to 50

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0
C)
13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V

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T7 T6 T5 T4 T3 T2 T1
T8
Brass Pin Fin
Heater

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38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.

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7. Do not exceed 200 W.
Procedure:
Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.

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2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.

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Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D

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2
) /4}?2gha m
3
/s.
Where, ha (head of air) = (?w / ?a) x H m

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H = Difference of water level in manometer m
?w Density of water = 1000 kg/m
3

?a = Density of air = 1.165 kg/m

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3
g = acceleration due to gravity = 9.81 m/s
2

Cd = Coefficient of discharge = 0.64

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D = diameter of the orifice
3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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A = area of the duct
4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?

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D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2
o
C

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5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number
6. Nusselt Number:
Nu = CRe
m

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(Pr)
0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m

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k= 386 w/mk
m= ?(hp/kA)
A = area of fin = (? x D
2
) /4

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L = Length of the fin
Tw ? average temperature
T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:

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Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

Outcome:

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From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.

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40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.

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4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer
6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction

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9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?
11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?

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14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.8

DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

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Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer

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(ii) Electric Heater
(iii) Stop watch
(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The

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outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A

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chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:

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1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve

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6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C

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= (or) 0.1 Kcal / kg
0
C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

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11. Temperature indicator digital 0.1
0

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C L.C 0 - 200
0
C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW

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13. Tank for hot water
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:

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Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4
? Td
4
)

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Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

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Schematic view of the test set-up:

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Heater

43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulations:

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Proc
edur
e:
1. H
eat the

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water
in the
tank by
the immersion heater up to a temperature of about 90
0

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C.
2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant

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cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

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Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m
2
k
4

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.

Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus

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is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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Sl. No.
Hemisphere Temperature(
0
C) Avg. Temp.

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of the
Hemisphere
(Th)
T4
Steady

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Temp. of
Disc
T0 (Td)
Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?
3. State Planck?s distribution law.

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4. Define ? Biot Number
5. State Wien?s displacement law.
6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.
8. What are the various types of convection?

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9. Define ? Condensation
10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?
13. State Krichoff's law or radiation

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14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.9

DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

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Aim:
To measure emissivity of the test plate surface at various temperature
Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer
Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide

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undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.

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Specifications:
1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.

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Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.

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9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300
0
C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.

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5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.
Tabulation:
Sl.
No

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Voltage

Current

Black body

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temp(
0
C)
Avg.
temp.

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Polished body
temp (
0
C)

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Avg.
temp.

Enclosure
Temp.

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(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:

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Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts
4
? Ta
4

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) A
Eb ? E = (W1 ? W2) / ? (Ts
4
? Ta
4

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) A
E = Eb ? {(W1 ? W2) / ? (Ts
4
? Ta
4

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) A}
Where,
W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd

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2
m
2

T = Temperature of black plate, k = (Ts + Ta) / 2

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Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)
Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

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47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

? = Stefan boltzman constant = 5.67 x 10
-8
W/m

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2
K
4

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Schematic view of the test set-up:


Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.

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And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by
the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

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Results:
The emissivity of the test plate surface is found to be _____________.
Outcome:
From this experiment, finding the emissivity of the test plate surface at various

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temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Emissivity

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2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?
4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?
6. What is meant by shape factor?

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7. Define ? Radiation
8. What is meant by monochromatic emissive power?
9. Define ? Emissive Power
10. What is meant by absorptivity?
11. Define ? Black Body

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12. What is meant by transmissivity?
13. State Plank's distribution law
14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.10

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EFFECTIVENESS OF PARALLEL / COUNTER
FLOW HEAT EXCHANGE

Aim:

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To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:
(i) Experimental Setup
(ii) Stop watch
(iii) Thermometer

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Theory:
Heat exchangers are classified in three categories:
1. Transfer type
2. Storage type
3. Direct contact type.

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A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.
The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.

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iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water
which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run

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as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:
1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm

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4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50
0
C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100

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0
C - 2 Nos.
7. Measuring flask = 0 ? 1000 CC

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8. Geyser: single phase type to obtain hot water supply
9. Thermo Cole insulation for outer pipe.
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically

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there is no temperature rise in the circuiting fluid.
Tabulations:
Sl.
No.
Flow Hot Fluid (

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0
C) Cold Fluid (
0
C)
Time for

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collection of
hot fluid
Kg/sec
Time for
collection

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of cold fluid
Kg/sec
1 Parallel flow
Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)
1. Area of the pipe A = ? (D ? d) L
Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube

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L = Length of the tube

2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

51 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Where, m = mass flow rate Kg/ sec.
m = ?v/t, ? = density of water and t = time taken for hot water
Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet

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Tho = Temperature of hot water outlet

3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W
Where, m = mass flow rate
Cp = Specific heat of capacity

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Tco = Temperature of cold water inlet
Tci = Temperature of cold water outlet
4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W
Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)

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?Tm = (?Ti - ?To) / In (?Ti/?To)
Where, ?To = Tho ? Tco
?Ti = Thi ? Tci
6. Over all heat transfer coefficient
h = Q?/?Tm A W/m

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2
K
where Q? = (Qa + Qc) / 2

Procedure:

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1. Place the thermometers in position and note down their readings when they are at room temperature and
no water is flowing at either side. This is required to correct the temperature.
2. Start the flow on hot water side.
3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.

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5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.
6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.
7. Keeping the flow rates same, wait till the steady state conditions are reached.
8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.

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10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Result:
1. The values of effectiveness of heat exchanger were found as
(i) Parallel flow = ________.
(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)

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(i) Parallel flow = ________.
(ii) Counter flow = _________.

Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow

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heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat
exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Heat Exchanger
2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?

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4. Write about the merits of drop wise condensation.
5. What is meant by film wise and drop wise condensation?
6. What is meant by effectiveness?
7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?

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9. Distinguish between regenerator and recuperates.
10. What is meant by parallel flow heat exchanger?
11. What is meant by counter flow heat exchanger?
12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?

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Viva ? voce

53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.11

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DETERMINATION OF COP OF A REFRIGERATION
SYSTEM

Aim:

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To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration
system
Apparatus required:
(i) Thermometer
(ii) Electric Heater

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(iii) Stop watch
(iv) Experimental setup
Description:
1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a
reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.

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2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated
wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a
low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the
temperature of chilled water. The above unit is located on the trolley behind front panel.
3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic

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expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum
strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure
gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high
pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy
meter to measure the power consumed either by hater or by compressor.

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54 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
A. A compressor condenser unit placed inside trolley and fitted with

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1. R-134a reciprocating compressor
2. Condenser
3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan
4. A receiver with angle check valve
B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity

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placed inside a well insulated wooden box and provided with
5. Evaporator coil
6. Stirrer
7. Electric heater 230 V, A.C.
8. The sensing bulb of low temperature thermostat.

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9. A high temperature thermostat.
10. A Thermometer to measure the chilled water temperature
C. The front panel on which are mounted the following
11. Capillary expansion tube with isolating valve.
12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator

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and isolating valve
13. Drier cum strainer and sight glass
14. Thermostat at inlet and outlet of both evaporator and condenser
15. Pressure gauge at inlet and outlet of evaporator and condenser
16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out

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17. Heat power regulator switch and regulator
18. Energy meter to measure the power consumed either by hater or by compressor.

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55 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.
2. The heater regulator should be switched off whenever not in use. Heating water beyond 40

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0
C may lead to
permanent damage of the entire system. A high temperature cut off thermostat is provided in the water
chiller, to cut off the heater beyond 30
0

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C.Check the setting of the same before operation.
3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.
4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.
5. The solenoid thermostat is adjusted to cut at 15
0

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C and cut in at 10
0
C of the chilled water. Do not alter the
same.
6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.

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7. The space near the condenser should permit good ventilation to aid proper fan performance.
8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked
in
0
F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,

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calibrated in SI units, are not available.)
9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to
obtain the pressure in MN/m
2
.e.g. P = x psig

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= (x + 14.7) psia
= (x + 14.7) / 145 MN/m
2
(MPa)
10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.

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Formulae used:
Let, State 1 indicates the entry of compressor.
State 2 indicates the exit of compressor.
State 3 indicates the exit from condenser.
State 4 indicates the entry to evaporator

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P = Pressure (bar)
T = Temperature (
0
C)
H = Specific enthalpy (kJ/kg)

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v = Specific Volume (m
3
/Kg)
n = Number of revolutions of energy meter disc.
t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)

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t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)
K = Energy meter constant = 3200 lmp / kWh
N = Speed of compressor = 2840 rpm
h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

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56 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2
h3 = Specific enthalpy at Pc and T3 (kJ/kg)
h4 = h3

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Stroke volume of compressor = (?/ 4) d
2
l = 12.58 x 10
-6
m

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3

1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar
2. Average condenser pressure, Pc = (P2 + P3) / 2 bar
3. Heater input, Qe = (n / t1) x (3600 / k) kW

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4. Compressor input, W = (n / t2) x (3600 / k) kW
5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1
6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)
7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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57 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

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Sl.
No.

Initial

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Temp.
of water

Final
Temp.

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of water
Duration
of exp.

Delivery

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pressure

Delivery
Temp.

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Condense
Outlet
Pressure

Condense

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Outlet
Temp.


Pressure

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after
throttling

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Temp.
After
Throttli

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ng


Suction
pressur

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e
Suction
Temp.

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Time for
10 rev. of
compress

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or energy
meter

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Height
of water
in the
vessel

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58 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
Load Test with Capillary tube as expansion device:
1. Fill the chilled water calorimeter with pure water so that the evaporative coils are
fully immersed.

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2. Select the capillary tube line by opening the shut-off valve on this line and closing
the one on the thermostatic expansion valve line. The solenoid switch is switched OFF.
3. Start the compressor and run for some time so that the chilled water temperature
is lowered to the given test temperature.
4. Switch on the heater and slowly increase the power.

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5. Allow The temperature in water calorimeter to reach the equilibrium
temperature.
6. Connect energy meter to motor and heater by the selector switch one after another
and note down the time taken for 10 pulses of the energy meter disc.
7. Note down the pressure and temperature readings at locations 1,2,3 & 4 as

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mentioned.
8. Switch OFF the heater and the mains.
Result:
The load test on a refrigeration test rig was conducted and the results are as follows.
1. Actual C.O.P. of the system =____________.

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2. Rhetorical C.O.P. of the system = ___________.
3. Volumetric Efficiency = ___________.

Outcome:
From this experiment, conducting the load test on a refrigeration test rig and finding out the

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volumetric efficiency and co-efficient of performance for any type of refrigerant is learnt and this experiment
could be used in the areas such as Refrigerator and Air Conditioning.
Applications:
Refrigerator, Air Conditioning.

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59 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? COP
2. Which thermodynamic cycle is used in air conditioning of airplanes using air as refrigerant?
3. Define ? Ton of Refrigeration

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4. What is meant by refrigeration?
5. What is meant by air conditioning?
6. What are the four important properties of a good refrigerant?
7. How does the actual vapour compression cycle differ from that of the ideal cycle?
8. Name any four commonly used refrigerants.

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9. What are the expansion devices used in a vapour compression plant?
10. Why throttle valve is used in place of expansion cylinder for vapour compression refrigerant machine?
11. What are the merits of air refrigeration system?
12. What are the demerits of air refrigeration system?
13. Define ? Refrigerant

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14. What is net refrigerating effect of the refrigerant?
15. What are the methods to obtain sub cooling of refrigerant?

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Viva ? voce

60 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.12 EXPERIMENTS ON PSYCHROMETRIC PROCESS

Aim:

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To conduct an experiment on psychrometric processes with air conditioning system
Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch

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(iv) Digital anemometer
(v) Experimental setup
Description:
The test rig consist of
1. An air duct support of stand

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2. A blower to set up air flow through the duct along with a speed control to vary the
velocity of air.
3. A heater to rise the air temperature with regulator and energy meter.
4. Water spray, collecting tray, reservoir with gauge pump.
5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.

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(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after cooling coil).
6. The test rig consist of compressor, condenser unit placed inside trolley and fitted
with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for
condenser and (iv) Liquid receiver.
7. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and

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corrosion damage.

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61 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Observation Table: I

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Precautions:
1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence
avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kw only for the motor
circuit.
2. Natural air currents in the room if in the direction of air duct may defect the experimental results and

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hence the duct should be placed such that no wind from doors, windows, fan and cooling air from
other test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan
and should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase
beyond 240 psi.
3. Never exceed dry bulb temperatures of 40

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0
C after the heater (station 2) otherwise the air duct may be
damaged.
4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may
exceed its maximum of 32

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0
C and calibration may be affected.
5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not
running this will lead to rise in temperature at the heater and may damage the heater and the air duct.
6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their

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duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.
7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer
is placed inside the reservoir at the top. This may have to the cleaned when necessary.
8. Do not open the gate valve fully otherwise water may be splashed outside and the waster
measurement may be in error.

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S.
N
o
Inlet temp
Outlet

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temp
Pressu
re
P1
Tem

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p.
T1
Pressu
re
P2

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Temp.
T2
Pressu
re
P3

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Tem
p.
T3

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Pressu
re
P4

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Temp.
T4
Energy
for 10

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revolutio
ns
Twet Tdry Twet Tdry Lb/in
o
C Lb/in

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o
C Lb/in
o
C Lb/in
o

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C


62 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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9. If the low pressure cut out comes in to action, it means that the Freon charge is insufficient and may
have to be filled up. The suction pressure should never go below 2 psi as otherwise the compressor
seals will be damaged and air and moisture may enter the system.
10. The refrigerant strainer placed on the front panel should always be warm. If it cools and moisture
condenser on it, then the strainer might have to be charged by an experienced refrigeration

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mechanics.
11. The refrigerating system can work continuously for 2 hours, however if the room temperature is above
25
0
C the condenser may be heated up and the delivery pressure may rise. Do not exceed 240 psi.

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Pour one or two glasses of drinking water over the fins of the condenser in order to reduce the
delivery pressure.
12. After some months of operation the compressor may have to be topped up with oil and some quantity
of Freon-22 may have to be charged by an experienced mechanics.
13. See that distilled water is filled up in the plastic dishes provided under the wet bulb thermometers and

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that the wicks are in tact otherwise erroneous readings may be obtained. These thermometers will
show correct readings only when the fan is in operation.
14. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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Formulae used:
1. Corresponding to the dry and wet bulb temperature at all the stations obtain the specific enthalpy and
specific humidity values from psychrometric chart.
i.e., h1 and w1 at tb1 and tw1 and so on.
2. Air flow rate, ma = (A x V) / v4 Kg / sec

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Where, A = Area of duct at outlet in m
2
(0.46 m x 0.086 m)
V = Air velocity ( m / sec)
V4 = Specific volume of moist air at station 4 using psychometric chart m

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3
/Kg
3. Moisture added from psychrometric chart, mw1 = ma (w3-w2) Kg / sec.
Where, w3 = Specific humidity at station 3
w2 = Specific humidity at station 2

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4. Cooling effect produced on air, Qe = ma (h3 ? h4) kW.
Where, h3 = Specific enthalpy at state 3 kJ/kg
h4 = Specific enthalpy at state 4 kJ/kg
5. Moisture condensed, mcl = ma (w3 ? w4) kg/sec
Where, w3 = Specific humidity at station 3

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w4 = Specific humidity at station 4

63 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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1. Fill water in the wet bulb temperature probe trays.
2. Start the main.
3. Start the blower and run it the required speed by keeping the speed regulator at
position.
4. Start the spray pump and open the gate valve suitably.

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5. Start the heater.
6. Select the expansion device (Capillary tube / Thermostatic expansion valve)
7. Start the cooling compressor.
8. Wait for some time till thermometers shown practically constant readings and note down the
following readings:

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(i) Dry bulb temperatures tdb1, tdb2, tdb3, tdb4.
(ii) Wet bulb temperatures twb1, twb2, twb3, twb4.
(iii) Spray water temperature, ts
(iv) Surface temperature of cooler, tm ( at control panel)
(v) Pressure gauge reading, pd ( at control panel)

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(vi) Compound gauge reading, Ps ( at control panel)
(vii) Level reduction?l? in spray reservoir (mm) during 5 min.
(viii) Amount of condensate collected ?lc?, in a measuring jar at cooler tray during a
run of 5 minutes at constant conditions.
(ix) Time in second ?SH? for 10 pulses of the energy meter disc connected to the

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heater.
(x) Time in seconds Sc for 10 pulses of the energy meter disc connected to cooler
compressor.
Result:
Experiment on psychrometric processes with air conditioning system was drawn

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Outcome:
From this experiment, conducting the test on psychrometric processes with air
conditioning system is learnt and this experiment could be used in all types of air conditioning systems.

Applications:

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Air Conditioning.


FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart

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and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

VISION
MISSION

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VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence

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To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design

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products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies

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5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering

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2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools

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6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms

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9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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--- Content provided by FirstRanker.com ---

6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder

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4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant

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9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system

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12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection

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experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.

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12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC

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Boiler.



COURSE OBJECTIVES

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COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS

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1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11

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3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21

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5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31

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7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47

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CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14

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Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate

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method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters

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together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples

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No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2

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(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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9 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help

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of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:

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1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm

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6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100

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0
C
9. Maximum temperature of the hot plate = 170
0
C

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10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V

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15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0

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C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:
Sl. No. Voltmeter
V

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Ammeter
A
Main heater (
0
C) Test Plate (

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0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:

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1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single

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phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.

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8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.

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3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?

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8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?

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13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?

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18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:

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To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple

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(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.

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There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.

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4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.

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4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging

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k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:

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Sl.
No.
Voltage
(V)
Current

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(A)
Heater Temperature
(
0
C)

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Asbestos Temperature
(
0
C)
Saw dust

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Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos

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layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:

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The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)

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6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?

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11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.

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16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical

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tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which

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in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.

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The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Schematic view of the test set-up:

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mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch

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Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples

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6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}

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Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W

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Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L
3

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?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v
2

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is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid

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v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity

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?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.

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hL / k = 0.56 (Gr.Pr)
0.25
for 10
4
< Gr.Pr.<10

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8

hL / k = 0.13 (Gr.Pr)
1/3
for 10

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8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).

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3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:

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The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m

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2
K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing

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heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?

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5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)

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10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness

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15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?

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20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:

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To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer

Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air

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stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of

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orifice meter and the water manometer fitted on the board.


24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

Sl. No. Voltage Current Temperature in (

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0
C)
Manometer
reading of water
in h in meter

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(V) (A)
T1

T2

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T3

T4

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T5

T6

h1

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cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor

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5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0
C

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(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:

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1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.

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6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.

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2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. The rate at which air is getting heated is calculated as

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qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o

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C)
= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate

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Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m
3
/hr

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3. ha = qa /A(Ts- Ta) W / m
2
K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m

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2

Ta = Average temperature of air = (T1 + T6)/2
o
C

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Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C
Cd = 0.64
H = Difference of water level in manometer m

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?w Density of water = 1000 Kg/m
3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

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d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

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using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2

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)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o
C

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5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

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27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k

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? = Viscosity Ns/m
2

k = Thermal conductivity of fluid W/m
2

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K
Nu = 0.023 (Re)
0.8
(Pr)
0.4

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Bulk mean temperature = (T1 + T6)/2

Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.

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hactual = -------------- W/m
2
K
htheoritical = -------------- W/m
2

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K

Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?

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3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?

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8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection

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13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

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Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,

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the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure

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temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat

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flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm

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2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.

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2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

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30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature

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gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:

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Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R

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Tabulation:
Sl.No. Voltmeter
reading
(V)
Ammeter

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reading
(A)
T1
(
0

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C)
T2
(
0
C)

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T3
(
0
C)
T4

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(
0
C)
T5
(

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0
C)
T6
(
0

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C)
T7
(
0
C)

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T8
(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Composite wall apparatus set-up

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Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W

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c. Asbestos section = ------------W

Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure

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Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?

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5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.

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9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

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33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

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DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

Aim:
To find out the thermal conductivity of insulating powder by conduction

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Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A

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multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

Procedure:

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1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.

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5. Repeat the experiments for different power inputs.


The readings are tabulated below

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Sl.No. Voltmeter
reading( V)
Ammeter
reading (A)
T1

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(
0
C)
T2
(

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0
C)
T3
(
0

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C)
T4
(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm

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The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Fig. 1 Apparatus of thermal conductivity of insulating powder

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[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

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Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam

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boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity

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3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.

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8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?

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13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?

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18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

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HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

Aim:

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To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is

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measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:
Sl.

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No.
V I

Fin Temperatures (
0

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C)
Ambient Temp
(
0
C)

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Manometer
Reading
(V)

(A)

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T1 T2 T3 T4 T5 T6 T7 T8
h1
cm
h2

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cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Duct size = 150 mm x 100 mm.

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2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

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Schematic view of the test set-up:



zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5

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10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C
12. Temperature indicator = 0 ? 300

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0
C
(With compensation of ambient temperature up-to 50
0
C)

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13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8

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Brass Pin Fin
Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.

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4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:

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Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.

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4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2

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Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m

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3
/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m

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3

?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s

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2

Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s

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Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

A = area of the duct

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4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.

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(T1 + T6) / 2
o
C
5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number

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6. Nusselt Number:
Nu = CRe
m
(Pr)
0.33

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7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk
m= ?(hp/kA)

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A = area of fin = (? x D
2
) /4
L = Length of the fin
Tw ? average temperature

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T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________

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Heat transfer, Q = ___________ W

Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.


40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer

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6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?

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11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.8

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DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

Aim:

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To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch

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(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water

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between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.

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When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere

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3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg

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8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C
= (or) 0.1 Kcal / kg
0

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C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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11. Temperature indicator digital 0.1
0
C L.C 0 - 200
0

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C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water
Precautions:

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Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4

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? Td
4
)
Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)

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Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

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43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulations:
Proc
edur

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e:
1. H
eat the
water
in the

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tank by
the immersion heater up to a temperature of about 90
0
C.
2. Remove the disc, D before pouring the hot water in the jacket.

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3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.

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6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m

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2
k
4
.

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Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using

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boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

Sl. No.

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Hemisphere Temperature(
0
C) Avg. Temp.
of the
Hemisphere

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(Th)
T4
Steady
Temp. of
Disc

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T0 (Td)
Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number
5. State Wien?s displacement law.

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6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation
10. What are the various modes of condensation?

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11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.9

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DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

Aim:

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To measure emissivity of the test plate surface at various temperature
Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The

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temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.
Specifications:
1. Heater input to black plate W1 = V1 x I1 W

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2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V

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6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300

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0
C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.

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Tabulation:
Sl.
No
Voltage

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Current

Black body
temp(
0

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C)
Avg.
temp.

Polished body

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temp (
0
C)
Avg.
temp.

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Enclosure
Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts

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4
? Ta
4
) A
Eb ? E = (W1 ? W2) / ? (Ts

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4
? Ta
4
) A
E = Eb ? {(W1 ? W2) / ? (Ts

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4
? Ta
4
) A}
Where,

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W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd
2
m

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2

T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)

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Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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? = Stefan boltzman constant = 5.67 x 10
-8
W/m
2
K

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4


Schematic view of the test set-up:

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Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by

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the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

Results:

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The emissivity of the test plate surface is found to be _____________.
Outcome:
From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

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48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Emissivity
2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?

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4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?
6. What is meant by shape factor?
7. Define ? Radiation
8. What is meant by monochromatic emissive power?

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9. Define ? Emissive Power
10. What is meant by absorptivity?
11. Define ? Black Body
12. What is meant by transmissivity?
13. State Plank's distribution law

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14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

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49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.10

EFFECTIVENESS OF PARALLEL / COUNTER

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FLOW HEAT EXCHANGE

Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:

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(i) Experimental Setup
(ii) Stop watch
(iii) Thermometer
Theory:
Heat exchangers are classified in three categories:

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1. Transfer type
2. Storage type
3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.

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The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water

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which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:

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1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50

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0
C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100
0
C - 2 Nos.

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7. Measuring flask = 0 ? 1000 CC

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8. Geyser: single phase type to obtain hot water supply

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9. Thermo Cole insulation for outer pipe.
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Tabulations:

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Sl.
No.
Flow Hot Fluid (
0
C) Cold Fluid (

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0
C)
Time for
collection of
hot fluid

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Kg/sec
Time for
collection
of cold fluid
Kg/sec

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1 Parallel flow
Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)

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1. Area of the pipe A = ? (D ? d) L
Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube
L = Length of the tube

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2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

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Where, m = mass flow rate Kg/ sec.

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m = ?v/t, ? = density of water and t = time taken for hot water
Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet
Tho = Temperature of hot water outlet

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3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W
Where, m = mass flow rate
Cp = Specific heat of capacity
Tco = Temperature of cold water inlet
Tci = Temperature of cold water outlet

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4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W
Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)
?Tm = (?Ti - ?To) / In (?Ti/?To)
Where, ?To = Tho ? Tco

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?Ti = Thi ? Tci
6. Over all heat transfer coefficient
h = Q?/?Tm A W/m
2
K

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where Q? = (Qa + Qc) / 2

Procedure:
1. Place the thermometers in position and note down their readings when they are at room temperature and
no water is flowing at either side. This is required to correct the temperature.

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2. Start the flow on hot water side.
3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.
5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.
6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.

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7. Keeping the flow rates same, wait till the steady state conditions are reached.
8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.
10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

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52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Result:
1. The values of effectiveness of heat exchanger were found as

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(i) Parallel flow = ________.
(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)
(i) Parallel flow = ________.
(ii) Counter flow = _________.

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Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow
heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat
exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Heat Exchanger
2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?
4. Write about the merits of drop wise condensation.
5. What is meant by film wise and drop wise condensation?

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6. What is meant by effectiveness?
7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?
9. Distinguish between regenerator and recuperates.
10. What is meant by parallel flow heat exchanger?

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11. What is meant by counter flow heat exchanger?
12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?
Viva ? voce

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53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.11

DETERMINATION OF COP OF A REFRIGERATION

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SYSTEM

Aim:
To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration
system

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Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Experimental setup

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Description:
1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a
reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.
2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated
wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a

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low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the
temperature of chilled water. The above unit is located on the trolley behind front panel.
3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic
expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum
strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure

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gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high
pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy
meter to measure the power consumed either by hater or by compressor.

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54 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
A. A compressor condenser unit placed inside trolley and fitted with
1. R-134a reciprocating compressor
2. Condenser

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3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan
4. A receiver with angle check valve
B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity
placed inside a well insulated wooden box and provided with
5. Evaporator coil

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6. Stirrer
7. Electric heater 230 V, A.C.
8. The sensing bulb of low temperature thermostat.
9. A high temperature thermostat.
10. A Thermometer to measure the chilled water temperature

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C. The front panel on which are mounted the following
11. Capillary expansion tube with isolating valve.
12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator
and isolating valve
13. Drier cum strainer and sight glass

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14. Thermostat at inlet and outlet of both evaporator and condenser
15. Pressure gauge at inlet and outlet of evaporator and condenser
16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out
17. Heat power regulator switch and regulator
18. Energy meter to measure the power consumed either by hater or by compressor.

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55 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.
2. The heater regulator should be switched off whenever not in use. Heating water beyond 40
0
C may lead to

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permanent damage of the entire system. A high temperature cut off thermostat is provided in the water
chiller, to cut off the heater beyond 30
0
C.Check the setting of the same before operation.
3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.

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4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.
5. The solenoid thermostat is adjusted to cut at 15
0
C and cut in at 10
0

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C of the chilled water. Do not alter the
same.
6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.
7. The space near the condenser should permit good ventilation to aid proper fan performance.
8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked

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in
0
F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,
calibrated in SI units, are not available.)
9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to

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obtain the pressure in MN/m
2
.e.g. P = x psig
= (x + 14.7) psia
= (x + 14.7) / 145 MN/m

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2
(MPa)
10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.
Formulae used:
Let, State 1 indicates the entry of compressor.

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State 2 indicates the exit of compressor.
State 3 indicates the exit from condenser.
State 4 indicates the entry to evaporator
P = Pressure (bar)
T = Temperature (

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0
C)
H = Specific enthalpy (kJ/kg)
v = Specific Volume (m
3

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/Kg)
n = Number of revolutions of energy meter disc.
t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)
t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)
K = Energy meter constant = 3200 lmp / kWh

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N = Speed of compressor = 2840 rpm
h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

56 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2
h3 = Specific enthalpy at Pc and T3 (kJ/kg)
h4 = h3
Stroke volume of compressor = (?/ 4) d
2

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l = 12.58 x 10
-6
m
3

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1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar
2. Average condenser pressure, Pc = (P2 + P3) / 2 bar
3. Heater input, Qe = (n / t1) x (3600 / k) kW
4. Compressor input, W = (n / t2) x (3600 / k) kW
5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1

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6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)
7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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57 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I


Sl.

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No.

Initial
Temp.
of water

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Final
Temp.
of water
Duration

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of exp.

Delivery
pressure

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Delivery
Temp.

Condense
Outlet

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Pressure

Condense
Outlet
Temp.

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Pressure
after
throttling

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Temp.
After
Throttli
ng

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Suction
pressur
e
Suction

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Temp.

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Time for
10 rev. of
compress
or energy
meter

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Height
of water

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in the
vessel

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58 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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Load Test with Capillary tube as expansion device:
1. Fill the chilled water calorimeter with pure water so that the evaporative coils are
fully immersed.
2. Select the capillary tube line by opening the shut-off valve on this line and closing
the one on the thermostatic expansion valve line. The solenoid switch is switched OFF.

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3. Start the compressor and run for some time so that the chilled water temperature
is lowered to the given test temperature.
4. Switch on the heater and slowly increase the power.
5. Allow The temperature in water calorimeter to reach the equilibrium
temperature.

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6. Connect energy meter to motor and heater by the selector switch one after another
and note down the time taken for 10 pulses of the energy meter disc.
7. Note down the pressure and temperature readings at locations 1,2,3 & 4 as
mentioned.
8. Switch OFF the heater and the mains.

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Result:
The load test on a refrigeration test rig was conducted and the results are as follows.
1. Actual C.O.P. of the system =____________.
2. Rhetorical C.O.P. of the system = ___________.
3. Volumetric Efficiency = ___________.

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Outcome:
From this experiment, conducting the load test on a refrigeration test rig and finding out the
volumetric efficiency and co-efficient of performance for any type of refrigerant is learnt and this experiment
could be used in the areas such as Refrigerator and Air Conditioning.

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Applications:
Refrigerator, Air Conditioning.

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59 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? COP
2. Which thermodynamic cycle is used in air conditioning of airplanes using air as refrigerant?
3. Define ? Ton of Refrigeration
4. What is meant by refrigeration?
5. What is meant by air conditioning?

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6. What are the four important properties of a good refrigerant?
7. How does the actual vapour compression cycle differ from that of the ideal cycle?
8. Name any four commonly used refrigerants.
9. What are the expansion devices used in a vapour compression plant?
10. Why throttle valve is used in place of expansion cylinder for vapour compression refrigerant machine?

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11. What are the merits of air refrigeration system?
12. What are the demerits of air refrigeration system?
13. Define ? Refrigerant
14. What is net refrigerating effect of the refrigerant?
15. What are the methods to obtain sub cooling of refrigerant?

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Viva ? voce

60 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.12 EXPERIMENTS ON PSYCHROMETRIC PROCESS

Aim:
To conduct an experiment on psychrometric processes with air conditioning system
Apparatus required:

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(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Digital anemometer
(v) Experimental setup

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Description:
The test rig consist of
1. An air duct support of stand
2. A blower to set up air flow through the duct along with a speed control to vary the
velocity of air.

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3. A heater to rise the air temperature with regulator and energy meter.
4. Water spray, collecting tray, reservoir with gauge pump.
5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.
(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after cooling coil).
6. The test rig consist of compressor, condenser unit placed inside trolley and fitted

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with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for
condenser and (iv) Liquid receiver.
7. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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61 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I

Precautions:
1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence

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avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kw only for the motor
circuit.
2. Natural air currents in the room if in the direction of air duct may defect the experimental results and
hence the duct should be placed such that no wind from doors, windows, fan and cooling air from
other test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan

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and should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase
beyond 240 psi.
3. Never exceed dry bulb temperatures of 40
0
C after the heater (station 2) otherwise the air duct may be

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damaged.
4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may
exceed its maximum of 32
0
C and calibration may be affected.

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5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not
running this will lead to rise in temperature at the heater and may damage the heater and the air duct.
6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their
duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.
7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer

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is placed inside the reservoir at the top. This may have to the cleaned when necessary.
8. Do not open the gate valve fully otherwise water may be splashed outside and the waster
measurement may be in error.
S.
N

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o
Inlet temp
Outlet
temp
Pressu

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re
P1
Tem
p.
T1

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Pressu
re
P2
Temp.
T2

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Pressu
re
P3

Tem

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p.
T3


Pressu

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re
P4


Temp.

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T4
Energy
for 10
revolutio
ns

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Twet Tdry Twet Tdry Lb/in
o
C Lb/in
o
C Lb/in

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o
C Lb/in
o
C

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62 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

9. If the low pressure cut out comes in to action, it means that the Freon charge is insufficient and may
have to be filled up. The suction pressure should never go below 2 psi as otherwise the compressor

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seals will be damaged and air and moisture may enter the system.
10. The refrigerant strainer placed on the front panel should always be warm. If it cools and moisture
condenser on it, then the strainer might have to be charged by an experienced refrigeration
mechanics.
11. The refrigerating system can work continuously for 2 hours, however if the room temperature is above

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25
0
C the condenser may be heated up and the delivery pressure may rise. Do not exceed 240 psi.
Pour one or two glasses of drinking water over the fins of the condenser in order to reduce the
delivery pressure.

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12. After some months of operation the compressor may have to be topped up with oil and some quantity
of Freon-22 may have to be charged by an experienced mechanics.
13. See that distilled water is filled up in the plastic dishes provided under the wet bulb thermometers and
that the wicks are in tact otherwise erroneous readings may be obtained. These thermometers will
show correct readings only when the fan is in operation.

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14. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

Formulae used:
1. Corresponding to the dry and wet bulb temperature at all the stations obtain the specific enthalpy and

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specific humidity values from psychrometric chart.
i.e., h1 and w1 at tb1 and tw1 and so on.
2. Air flow rate, ma = (A x V) / v4 Kg / sec
Where, A = Area of duct at outlet in m
2

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(0.46 m x 0.086 m)
V = Air velocity ( m / sec)
V4 = Specific volume of moist air at station 4 using psychometric chart m
3
/Kg

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3. Moisture added from psychrometric chart, mw1 = ma (w3-w2) Kg / sec.
Where, w3 = Specific humidity at station 3
w2 = Specific humidity at station 2
4. Cooling effect produced on air, Qe = ma (h3 ? h4) kW.
Where, h3 = Specific enthalpy at state 3 kJ/kg

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h4 = Specific enthalpy at state 4 kJ/kg
5. Moisture condensed, mcl = ma (w3 ? w4) kg/sec
Where, w3 = Specific humidity at station 3
w4 = Specific humidity at station 4

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63 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Fill water in the wet bulb temperature probe trays.
2. Start the main.

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3. Start the blower and run it the required speed by keeping the speed regulator at
position.
4. Start the spray pump and open the gate valve suitably.
5. Start the heater.
6. Select the expansion device (Capillary tube / Thermostatic expansion valve)

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7. Start the cooling compressor.
8. Wait for some time till thermometers shown practically constant readings and note down the
following readings:
(i) Dry bulb temperatures tdb1, tdb2, tdb3, tdb4.
(ii) Wet bulb temperatures twb1, twb2, twb3, twb4.

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(iii) Spray water temperature, ts
(iv) Surface temperature of cooler, tm ( at control panel)
(v) Pressure gauge reading, pd ( at control panel)
(vi) Compound gauge reading, Ps ( at control panel)
(vii) Level reduction?l? in spray reservoir (mm) during 5 min.

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(viii) Amount of condensate collected ?lc?, in a measuring jar at cooler tray during a
run of 5 minutes at constant conditions.
(ix) Time in second ?SH? for 10 pulses of the energy meter disc connected to the
heater.
(x) Time in seconds Sc for 10 pulses of the energy meter disc connected to cooler

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compressor.
Result:
Experiment on psychrometric processes with air conditioning system was drawn
Outcome:
From this experiment, conducting the test on psychrometric processes with air

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conditioning system is learnt and this experiment could be used in all types of air conditioning systems.

Applications:
Air Conditioning.

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64 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the commonly used unit of refrigeration?
2. Distinguish between summer air conditioning and winter air conditioning.
3. Define ? RSHF Line
4. Define ? By Pass Factor of a Heating Coil

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5. What is the effect of sub cooling a refrigerant in a vapour compression cycle?
6. What is the function of analyzer and rectifier in an absorption system?
7. What is the purpose of generator assembly in vapour absorption refrigeration system?
8. State the substance used in the Lithium Bromide system and their functions.
9. Differentiate wet compression from dry compression.

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10. Define ? Apparatus Dew Point
11. What is meant by dew point temperature?
12. Define ? Wet Bulb Temperature
13. Define ? Degree of Saturation
14. What is meant by specific humidity?

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15. Define ? Relative Humidity

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Viva ? voce
FirstRanker.com - FirstRanker's Choice

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1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL

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2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels

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? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION

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MISSION
VISION
MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals

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2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which

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enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt

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and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able

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1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution

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5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both

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verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus

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3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)

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8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:

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11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus

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3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction

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7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-

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efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.

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15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
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CONTENTS

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Sl.No.
Name of the experiment
Page No.

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CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus

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11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15

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4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6

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Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43

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10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63

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14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75

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PROJECT WORK 81

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Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:

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To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in

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which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.

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Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d

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2
(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.

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4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

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Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm

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5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0

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C ? 100
0
C
9. Maximum temperature of the hot plate = 170
0

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C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V

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14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200

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0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter

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V
Ammeter
A
Main heater (
0

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C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.

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3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.

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7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be

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k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat

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exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity

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2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?

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7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.

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12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.

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17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

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Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus

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(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is

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transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside

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an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm

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3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.

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3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)

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Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found

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Tabulation:
Sl.
No.
Voltage
(V)

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Current
(A)
Heater Temperature
(
0

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C)
Asbestos Temperature
(
0
C)

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Saw dust
Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.

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5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.

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Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?

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5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?

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10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow

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15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.

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20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:

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To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of

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the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

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When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Schematic view of the test set-up:
mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm

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4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel

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thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0

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c)

V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Heat transfer coefficient is given by

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h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m

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2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C

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q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L

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3
?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v

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2
is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface

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K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid

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G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K

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-1

Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been

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determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25
for 10
4

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< Gr.Pr.<10
8

hL / k = 0.13 (Gr.Pr)
1/3

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for 10
8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.

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2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

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Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K

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Experimental = ______________ W/ m
2
K

Outcomes:

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From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.

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4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.

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9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?

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14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness

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19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

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Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer

Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band

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heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to

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measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.


24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

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Sl. No. Voltage Current Temperature in (
0
C)
Manometer
reading of water

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in h in meter

(V) (A)
T1

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T2

T3

T4

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T5

T6

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h1
cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm

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4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0

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C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.

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5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference

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in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.

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4. Note down the heater input.

26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:

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1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (

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o
C)
= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr

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Q = Volume flow rate
Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m
3

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/hr
3. ha = qa /A(Ts- Ta) W / m
2
K
qa = Rate of which air is getting heated.

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A = Test section area = ? x Di x L m
2

Ta = Average temperature of air = (T1 + T6)/2
o

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C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C
Cd = 0.64

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H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m

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3

d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

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using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di

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2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o

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C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings

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6. Prandtl Number:

27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k

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Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

k = Thermal conductivity of fluid W/m

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2
K
Nu = 0.023 (Re)
0.8
(Pr)

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0.4
Bulk mean temperature = (T1 + T6)/2

Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection

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apparatus.
hactual = -------------- W/m
2
K
htheoritical = -------------- W/m

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2
K

Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection

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apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is meant by boiling and condensation?

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2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?

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7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?

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12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:

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When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly

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temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The

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apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:

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1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:

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1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.

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5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)

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6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.

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Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities

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Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter
reading
(V)

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Ammeter
reading
(A)
T1
(

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0
C)
T2
(
0

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C)
T3
(
0
C)

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T4
(
0
C)
T5

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(
0
C)
T6
(

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0
C)
T7
(
0

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C)
T8
(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W

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b. Wood section = ---------------W
c. Asbestos section = ------------W

Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt

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and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.

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4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.

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8. Explain the significance of Fourier number.
9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

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DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

Aim:

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To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and

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T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

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Procedure:

1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.

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4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.


The readings are tabulated below

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Sl.No. Voltmeter
reading( V)
Ammeter
reading (A)

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T1
(
0
C)
T2

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(
0
C)
T3
(

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0
C)
T4
(
0

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C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm

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The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Fig. 1 Apparatus of thermal conductivity of insulating powder

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[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

Result:

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The thermal conductivity of insulating powder by conduction is found and the result is, ___________

Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is

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analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is the need for conducting this experiment?

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2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.

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7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?

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12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?

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17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.7

HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

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Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer
Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the

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fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:

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Sl.
No.
V I

Fin Temperatures (

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0
C)
Ambient Temp
(
0

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C)
Manometer
Reading
(V)

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(A)

T1 T2 T3 T4 T5 T6 T7 T8
h1
cm

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h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

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Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor

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9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C

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12. Temperature indicator = 0 ? 300
0
C
(With compensation of ambient temperature up-to 50
0

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C)
13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1

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T8
Brass Pin Fin
Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.

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3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.

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Procedure:
Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.

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3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)

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1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2

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) /4}?2gha m
3
/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m

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?w Density of water = 1000 kg/m
3

?a = Density of air = 1.165 kg/m
3

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g = acceleration due to gravity = 9.81 m/s
2

Cd = Coefficient of discharge = 0.64
D = diameter of the orifice

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3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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A = area of the duct
4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin

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v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2
o
C
5. Heat transfer coefficient, h = Nu k / D

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Where Nu = Nusselt Number
6. Nusselt Number:
Nu = CRe
m
(Pr)

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0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk

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m= ?(hp/kA)
A = area of fin = (? x D
2
) /4
L = Length of the fin

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Tw ? average temperature
T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were

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Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced

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convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.

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40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?

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5. Define ? Heat Transfer
6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?

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10. What is meant by steady state heat conduction?
11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number

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15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.8

DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

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Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer
(ii) Electric Heater

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(iii) Stop watch
(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.

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The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on

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the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm

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2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm

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7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C
= (or) 0.1 Kcal / kg

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0
C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

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11. Temperature indicator digital 0.1
0
C L.C 0 - 200

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0
C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water

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Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th

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4
? Td
4
)
Where, A = area of the disc

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Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

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43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulations:
Proc

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edur
e:
1. H
eat the
water

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in the
tank by
the immersion heater up to a temperature of about 90
0
C.

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2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.

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5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

Result:

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The Stefan Boltzman constant was found out to be = _______________________ m/m
2
k
4
.

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Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,

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Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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Sl. No.
Hemisphere Temperature(
0
C) Avg. Temp.
of the

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Hemisphere
(Th)
T4
Steady
Temp. of

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Disc
T0 (Td)
Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number

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5. State Wien?s displacement law.
6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation

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10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?

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15. Explain the concept of black body.

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Viva ? voce

45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.9

DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

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Aim:
To measure emissivity of the test plate surface at various temperature
Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer
Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats

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and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.
Specifications:

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1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each

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5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.

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10. Temperature Indicator = 0 ? 300
0
C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:

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1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.

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6. See that the black plate is having a layer of lamp black uniformly.
Tabulation:
Sl.
No
Voltage

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Current

Black body
temp(

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0
C)
Avg.
temp.

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Polished body
temp (
0
C)
Avg.

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temp.

Enclosure
Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,

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W1 ? W2 = (Eb ? E) ? (Ts
4
? Ta
4
) A

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Eb ? E = (W1 ? W2) / ? (Ts
4
? Ta
4
) A

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E = Eb ? {(W1 ? W2) / ? (Ts
4
? Ta
4
) A}

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Where,
W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd
2

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m
2

T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure

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Ts = surface temperature of the discs (or T1)
Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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? = Stefan boltzman constant = 5.67 x 10
-8
W/m
2

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K
4


Schematic view of the test set-up:

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Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,

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2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by
the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

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Results:
The emissivity of the test plate surface is found to be _____________.
Outcome:
From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Emissivity
2. State Kirchoff?s law of radiation.

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3. What is meant by reflectivity?
4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?
6. What is meant by shape factor?
7. Define ? Radiation

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8. What is meant by monochromatic emissive power?
9. Define ? Emissive Power
10. What is meant by absorptivity?
11. Define ? Black Body
12. What is meant by transmissivity?

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13. State Plank's distribution law
14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

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49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.10

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EFFECTIVENESS OF PARALLEL / COUNTER
FLOW HEAT EXCHANGE

Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow

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Apparatus required:
(i) Experimental Setup
(ii) Stop watch
(iii) Thermometer
Theory:

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Heat exchangers are classified in three categories:
1. Transfer type
2. Storage type
3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is

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transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.
The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.

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The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water
which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.

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Specifications:
1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm

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5. Thermometers (for cold water) = 0 ? 50
0
C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100
0

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C - 2 Nos.
7. Measuring flask = 0 ? 1000 CC

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8. Geyser: single phase type to obtain hot water supply
9. Thermo Cole insulation for outer pipe.
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.

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Tabulations:
Sl.
No.
Flow Hot Fluid (
0

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C) Cold Fluid (
0
C)
Time for
collection of

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hot fluid
Kg/sec
Time for
collection
of cold fluid

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Kg/sec
1 Parallel flow
Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)
1. Area of the pipe A = ? (D ? d) L
Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube
L = Length of the tube

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2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

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Where, m = mass flow rate Kg/ sec.
m = ?v/t, ? = density of water and t = time taken for hot water
Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet
Tho = Temperature of hot water outlet

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3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W
Where, m = mass flow rate
Cp = Specific heat of capacity
Tco = Temperature of cold water inlet

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Tci = Temperature of cold water outlet
4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W
Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)
?Tm = (?Ti - ?To) / In (?Ti/?To)

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Where, ?To = Tho ? Tco
?Ti = Thi ? Tci
6. Over all heat transfer coefficient
h = Q?/?Tm A W/m
2

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K
where Q? = (Qa + Qc) / 2

Procedure:
1. Place the thermometers in position and note down their readings when they are at room temperature and

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no water is flowing at either side. This is required to correct the temperature.
2. Start the flow on hot water side.
3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.
5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.

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6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.
7. Keeping the flow rates same, wait till the steady state conditions are reached.
8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.
10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

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52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Result:

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1. The values of effectiveness of heat exchanger were found as
(i) Parallel flow = ________.
(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)
(i) Parallel flow = ________.

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(ii) Counter flow = _________.

Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow
heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat

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exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Heat Exchanger
2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?
4. Write about the merits of drop wise condensation.

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5. What is meant by film wise and drop wise condensation?
6. What is meant by effectiveness?
7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?
9. Distinguish between regenerator and recuperates.

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10. What is meant by parallel flow heat exchanger?
11. What is meant by counter flow heat exchanger?
12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?
Viva ? voce

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53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.11

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DETERMINATION OF COP OF A REFRIGERATION
SYSTEM

Aim:
To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration

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system
Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch

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(iv) Experimental setup
Description:
1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a
reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.
2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated

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wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a
low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the
temperature of chilled water. The above unit is located on the trolley behind front panel.
3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic
expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum

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strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure
gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high
pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy
meter to measure the power consumed either by hater or by compressor.

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54 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
A. A compressor condenser unit placed inside trolley and fitted with
1. R-134a reciprocating compressor

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2. Condenser
3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan
4. A receiver with angle check valve
B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity
placed inside a well insulated wooden box and provided with

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5. Evaporator coil
6. Stirrer
7. Electric heater 230 V, A.C.
8. The sensing bulb of low temperature thermostat.
9. A high temperature thermostat.

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10. A Thermometer to measure the chilled water temperature
C. The front panel on which are mounted the following
11. Capillary expansion tube with isolating valve.
12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator
and isolating valve

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13. Drier cum strainer and sight glass
14. Thermostat at inlet and outlet of both evaporator and condenser
15. Pressure gauge at inlet and outlet of evaporator and condenser
16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out
17. Heat power regulator switch and regulator

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18. Energy meter to measure the power consumed either by hater or by compressor.



55 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.
2. The heater regulator should be switched off whenever not in use. Heating water beyond 40
0

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C may lead to
permanent damage of the entire system. A high temperature cut off thermostat is provided in the water
chiller, to cut off the heater beyond 30
0
C.Check the setting of the same before operation.

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3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.
4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.
5. The solenoid thermostat is adjusted to cut at 15
0
C and cut in at 10

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0
C of the chilled water. Do not alter the
same.
6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.
7. The space near the condenser should permit good ventilation to aid proper fan performance.

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8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked
in
0
F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,
calibrated in SI units, are not available.)

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9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to
obtain the pressure in MN/m
2
.e.g. P = x psig
= (x + 14.7) psia

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= (x + 14.7) / 145 MN/m
2
(MPa)
10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.
Formulae used:

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Let, State 1 indicates the entry of compressor.
State 2 indicates the exit of compressor.
State 3 indicates the exit from condenser.
State 4 indicates the entry to evaporator
P = Pressure (bar)

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T = Temperature (
0
C)
H = Specific enthalpy (kJ/kg)
v = Specific Volume (m

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3
/Kg)
n = Number of revolutions of energy meter disc.
t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)
t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)

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K = Energy meter constant = 3200 lmp / kWh
N = Speed of compressor = 2840 rpm
h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

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h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2
h3 = Specific enthalpy at Pc and T3 (kJ/kg)
h4 = h3
Stroke volume of compressor = (?/ 4) d

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2
l = 12.58 x 10
-6
m
3

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1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar
2. Average condenser pressure, Pc = (P2 + P3) / 2 bar
3. Heater input, Qe = (n / t1) x (3600 / k) kW
4. Compressor input, W = (n / t2) x (3600 / k) kW

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5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1
6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)
7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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57 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

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Sl.
No.

Initial
Temp.

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of water

Final
Temp.
of water

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Duration
of exp.

Delivery
pressure

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Delivery
Temp.

Condense

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Outlet
Pressure

Condense
Outlet

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Temp.


Pressure
after

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throttling

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Temp.
After
Throttli
ng

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Suction
pressur
e

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Suction
Temp.

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Time for
10 rev. of
compress
or energy

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meter



Height

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of water
in the
vessel

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58 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
Load Test with Capillary tube as expansion device:
1. Fill the chilled water calorimeter with pure water so that the evaporative coils are
fully immersed.
2. Select the capillary tube line by opening the shut-off valve on this line and closing

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the one on the thermostatic expansion valve line. The solenoid switch is switched OFF.
3. Start the compressor and run for some time so that the chilled water temperature
is lowered to the given test temperature.
4. Switch on the heater and slowly increase the power.
5. Allow The temperature in water calorimeter to reach the equilibrium

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temperature.
6. Connect energy meter to motor and heater by the selector switch one after another
and note down the time taken for 10 pulses of the energy meter disc.
7. Note down the pressure and temperature readings at locations 1,2,3 & 4 as
mentioned.

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8. Switch OFF the heater and the mains.
Result:
The load test on a refrigeration test rig was conducted and the results are as follows.
1. Actual C.O.P. of the system =____________.
2. Rhetorical C.O.P. of the system = ___________.

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3. Volumetric Efficiency = ___________.

Outcome:
From this experiment, conducting the load test on a refrigeration test rig and finding out the
volumetric efficiency and co-efficient of performance for any type of refrigerant is learnt and this experiment

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could be used in the areas such as Refrigerator and Air Conditioning.
Applications:
Refrigerator, Air Conditioning.

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59 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? COP
2. Which thermodynamic cycle is used in air conditioning of airplanes using air as refrigerant?
3. Define ? Ton of Refrigeration
4. What is meant by refrigeration?

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5. What is meant by air conditioning?
6. What are the four important properties of a good refrigerant?
7. How does the actual vapour compression cycle differ from that of the ideal cycle?
8. Name any four commonly used refrigerants.
9. What are the expansion devices used in a vapour compression plant?

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10. Why throttle valve is used in place of expansion cylinder for vapour compression refrigerant machine?
11. What are the merits of air refrigeration system?
12. What are the demerits of air refrigeration system?
13. Define ? Refrigerant
14. What is net refrigerating effect of the refrigerant?

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15. What are the methods to obtain sub cooling of refrigerant?

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Viva ? voce

60 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.12 EXPERIMENTS ON PSYCHROMETRIC PROCESS

Aim:
To conduct an experiment on psychrometric processes with air conditioning system

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Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Digital anemometer

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(v) Experimental setup
Description:
The test rig consist of
1. An air duct support of stand
2. A blower to set up air flow through the duct along with a speed control to vary the

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velocity of air.
3. A heater to rise the air temperature with regulator and energy meter.
4. Water spray, collecting tray, reservoir with gauge pump.
5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.
(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after cooling coil).

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6. The test rig consist of compressor, condenser unit placed inside trolley and fitted
with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for
condenser and (iv) Liquid receiver.
7. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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61 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I

Precautions:

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1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence
avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kw only for the motor
circuit.
2. Natural air currents in the room if in the direction of air duct may defect the experimental results and
hence the duct should be placed such that no wind from doors, windows, fan and cooling air from

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other test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan
and should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase
beyond 240 psi.
3. Never exceed dry bulb temperatures of 40
0

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C after the heater (station 2) otherwise the air duct may be
damaged.
4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may
exceed its maximum of 32
0

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C and calibration may be affected.
5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not
running this will lead to rise in temperature at the heater and may damage the heater and the air duct.
6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their
duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.

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7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer
is placed inside the reservoir at the top. This may have to the cleaned when necessary.
8. Do not open the gate valve fully otherwise water may be splashed outside and the waster
measurement may be in error.
S.

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N
o
Inlet temp
Outlet
temp

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Pressu
re
P1
Tem
p.

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T1
Pressu
re
P2
Temp.

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T2
Pressu
re
P3

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Tem
p.
T3

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Pressu
re
P4

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Temp.
T4
Energy
for 10
revolutio

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ns
Twet Tdry Twet Tdry Lb/in
o
C Lb/in
o

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C Lb/in
o
C Lb/in
o
C

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62 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

9. If the low pressure cut out comes in to action, it means that the Freon charge is insufficient and may

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have to be filled up. The suction pressure should never go below 2 psi as otherwise the compressor
seals will be damaged and air and moisture may enter the system.
10. The refrigerant strainer placed on the front panel should always be warm. If it cools and moisture
condenser on it, then the strainer might have to be charged by an experienced refrigeration
mechanics.

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11. The refrigerating system can work continuously for 2 hours, however if the room temperature is above
25
0
C the condenser may be heated up and the delivery pressure may rise. Do not exceed 240 psi.
Pour one or two glasses of drinking water over the fins of the condenser in order to reduce the

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delivery pressure.
12. After some months of operation the compressor may have to be topped up with oil and some quantity
of Freon-22 may have to be charged by an experienced mechanics.
13. See that distilled water is filled up in the plastic dishes provided under the wet bulb thermometers and
that the wicks are in tact otherwise erroneous readings may be obtained. These thermometers will

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show correct readings only when the fan is in operation.
14. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

Formulae used:

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1. Corresponding to the dry and wet bulb temperature at all the stations obtain the specific enthalpy and
specific humidity values from psychrometric chart.
i.e., h1 and w1 at tb1 and tw1 and so on.
2. Air flow rate, ma = (A x V) / v4 Kg / sec
Where, A = Area of duct at outlet in m

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2
(0.46 m x 0.086 m)
V = Air velocity ( m / sec)
V4 = Specific volume of moist air at station 4 using psychometric chart m
3

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/Kg
3. Moisture added from psychrometric chart, mw1 = ma (w3-w2) Kg / sec.
Where, w3 = Specific humidity at station 3
w2 = Specific humidity at station 2
4. Cooling effect produced on air, Qe = ma (h3 ? h4) kW.

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Where, h3 = Specific enthalpy at state 3 kJ/kg
h4 = Specific enthalpy at state 4 kJ/kg
5. Moisture condensed, mcl = ma (w3 ? w4) kg/sec
Where, w3 = Specific humidity at station 3
w4 = Specific humidity at station 4

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63 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Fill water in the wet bulb temperature probe trays.

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2. Start the main.
3. Start the blower and run it the required speed by keeping the speed regulator at
position.
4. Start the spray pump and open the gate valve suitably.
5. Start the heater.

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6. Select the expansion device (Capillary tube / Thermostatic expansion valve)
7. Start the cooling compressor.
8. Wait for some time till thermometers shown practically constant readings and note down the
following readings:
(i) Dry bulb temperatures tdb1, tdb2, tdb3, tdb4.

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(ii) Wet bulb temperatures twb1, twb2, twb3, twb4.
(iii) Spray water temperature, ts
(iv) Surface temperature of cooler, tm ( at control panel)
(v) Pressure gauge reading, pd ( at control panel)
(vi) Compound gauge reading, Ps ( at control panel)

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(vii) Level reduction?l? in spray reservoir (mm) during 5 min.
(viii) Amount of condensate collected ?lc?, in a measuring jar at cooler tray during a
run of 5 minutes at constant conditions.
(ix) Time in second ?SH? for 10 pulses of the energy meter disc connected to the
heater.

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(x) Time in seconds Sc for 10 pulses of the energy meter disc connected to cooler
compressor.
Result:
Experiment on psychrometric processes with air conditioning system was drawn
Outcome:

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From this experiment, conducting the test on psychrometric processes with air
conditioning system is learnt and this experiment could be used in all types of air conditioning systems.

Applications:
Air Conditioning.

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64 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the commonly used unit of refrigeration?
2. Distinguish between summer air conditioning and winter air conditioning.
3. Define ? RSHF Line

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4. Define ? By Pass Factor of a Heating Coil
5. What is the effect of sub cooling a refrigerant in a vapour compression cycle?
6. What is the function of analyzer and rectifier in an absorption system?
7. What is the purpose of generator assembly in vapour absorption refrigeration system?
8. State the substance used in the Lithium Bromide system and their functions.

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9. Differentiate wet compression from dry compression.
10. Define ? Apparatus Dew Point
11. What is meant by dew point temperature?
12. Define ? Wet Bulb Temperature
13. Define ? Degree of Saturation

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14. What is meant by specific humidity?
15. Define ? Relative Humidity

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Viva ? voce

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65 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.13

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PERFORMANCE TEST ON A RECIPROCATING
AIR COMPRESSOR

Aim:
To conduct a load test on the 2 - stage reciprocating air compressor to determine the isothermal and

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volumetric Efficiencies at various delivery pressures

Apparatus required:
* Air compressor with accessories.
* Stop watch.

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Description:
Two stage air compressors is a reciprocating type driven by a prime mover. The test rig consist of a base on
which the tank is mounted. The outlet of the compressor is connected to the receiver. The suction is
connected to air tank with a calibrated orifice plate through a water manometer. The input to the motor is
recorded by an energy meter. The temperature and pressure of the air compressed is indicated by a

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thermometer and pressure gauge.
Specifications:
1. Air compressor:
* LP Bore, DLP = 63.0 mm.
* HP Bore, DHP = 79.0 mm.

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* Stroke, L = 80.0 mm.
* Speed, N = 1440 rpm (5 HP)
* Effective radius = 0.193 m
2. Air receiver capacity = 0.33 m3
3. Orifice, diameter, d0 = 12 mm

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4. Orifice area,. A0 : ?d0
2
/ 4 = ----------- m
2

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5. Coefficient of discharge C d. = 0.6
6. Energy-meter constant = 200 rev / kWh
FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION

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MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex

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software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills

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4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning

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To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the

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career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society

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7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with

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coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:

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HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube

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5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface

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10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes

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13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.

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4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system

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13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES

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7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6

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2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3

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Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5

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Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7

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Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS

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11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68

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15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT

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USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate

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assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The

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heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:

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1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2

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Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently

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5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm

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2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm

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7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100
0

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C
9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm

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11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A

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16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C

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19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter
V
Ammeter

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A
Main heater (
0
C) Test Plate (
0

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C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.

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Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.

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4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.

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4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?

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9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?

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14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?

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19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF

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PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus

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Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter

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(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm

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5. The effective length of the above = 500 mm

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Precautions:

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1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W

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Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material

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k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.

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No.
Voltage
(V)
Current
(A)

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Heater Temperature
(
0
C)
Asbestos Temperature

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(
0
C)
Saw dust
Temperature (

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0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.

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2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.

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6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.

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The thermal conductivity of resistive material = _________________ W /m
2
-K

Outcome:

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From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:

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Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. Define ? Nusselt Number(Nu)

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2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)

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7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?

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12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?

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17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION

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FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The

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temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold

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fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Schematic view of the test set-up:
mm

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mm

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Specifications:

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1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.

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5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A

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7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

Tabulation:

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Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m

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2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (

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0
C) ?
2. hL / k = A { g L
3
?T Cp ?/2v

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2
}
n

Where, hL / k are called Nusselt Number.

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L
3
g?T / v
2
is called Grashof number.

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?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid

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? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta

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For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)

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0.25
for 10
4
< Gr.Pr.<10
8

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hL / k = 0.13 (Gr.Pr)
1/3
for 10
8

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< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.

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4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as

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Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m
2

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K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC

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engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?

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6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?

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11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.

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16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to

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the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

Sl. No. Voltage Current Temperature in (
0

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C)
Manometer
reading of water
in h in meter

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(V) (A)
T1

T2

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T3

T4

T5

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T6

h1
cm

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h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer

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6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0
C
(Calibrated for chromel alumel thermocouple)

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8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.

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7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat

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input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)

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Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o
C)

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= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di

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2
?2gH x (?w / ?a) m
3
/hr
3. ha = qa /A(Ts- Ta) W / m

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2
K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

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Ta = Average temperature of air = (T1 + T6)/2
o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4

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o
C
Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m

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3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

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d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

using this procedure obtain the value of ?ha? for different air flow rate

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4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2
)/4]

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v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o
C
5. Nusselt Number:

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Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

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27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m

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2

k = Thermal conductivity of fluid W/m
2
K

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Nu = 0.023 (Re)
0.8
(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

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Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m

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2
K
htheoritical = -------------- W/m
2
K

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Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?

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4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?

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9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.

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14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

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29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

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Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the

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thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The

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temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is

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the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm

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3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat

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input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

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30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.

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7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow

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R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:

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Sl.No. Voltmeter
reading
(V)
Ammeter
reading

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(A)
T1
(
0
C)

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T2
(
0
C)
T3

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(
0
C)
T4
(

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0
C)
T5
(
0

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C)
T6
(
0
C)

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T7
(
0
C)
T8

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(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Composite wall apparatus set-up

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Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

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Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal

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conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?

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10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

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33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY

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OF INSULATING POWDER

Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

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The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit

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is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

Procedure:

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1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter

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reading( V)
Ammeter
reading (A)
T1
(

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0
C)
T2
(
0

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C)
T3
(
0
C)

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T4
(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1

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Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.


34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Fig. 1 Apparatus of thermal conductivity of insulating powder

[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater

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control]

Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

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Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to

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be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?

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4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?

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9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)

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14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?

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19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

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36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

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HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:

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A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is

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shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:
Sl.
No.

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V I

Fin Temperatures (
0
C)

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Ambient Temp
(
0
C)
Manometer

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Reading
(V)

(A)

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T1 T2 T3 T4 T5 T6 T7 T8
h1
cm
h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm

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3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.

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11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C
12. Temperature indicator = 0 ? 300
0

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C
(With compensation of ambient temperature up-to 50
0
C)
13. Dimmer stat for heat input controls 230 V, 2 A

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14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8
Brass Pin Fin

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Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

16. Ammeter = 0 ? 2 A

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.

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5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:
Forced Convection:

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1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient

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temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)

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Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m
3

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/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m
3

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?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s
2

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Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

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39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

A = area of the duct
4. Reynold?s Number:

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Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2

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o
C
5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number
6. Nusselt Number:

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Nu = CRe
m
(Pr)
0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)

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h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk
m= ?(hp/kA)
A = area of fin = (? x D

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2
) /4
L = Length of the fin
Tw ? average temperature
T? ? ambient (surface) temperature (T6)

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8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

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Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through

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pin-fin is to be found.


40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Extended Surface

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2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer
6. Define ? Fin Efficiency

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7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?
11. Define ? Convection

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12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

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41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.8

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DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus

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Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Geyser water

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Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to

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measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response

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of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm

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4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg

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0
C
= (or) 0.1 Kcal / kg
0
C

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9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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11. Temperature indicator digital 0.1
0
C L.C 0 - 200
0
C with built-in cold junction compensation and a timer set

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for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically

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there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4
? Td

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4
)
Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0

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dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:
Proc
edur
e:

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1. H
eat the
water
in the
tank by

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the immersion heater up to a temperature of about 90
0
C.
2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.

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4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate

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thermocouple).

Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m
2

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k
4
.

Outcome:

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From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.

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.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

Sl. No.
Hemisphere Temperature(

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0
C) Avg. Temp.
of the
Hemisphere
(Th)

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T4
Steady
Temp. of
Disc
T0 (Td)

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Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]

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2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number
5. State Wien?s displacement law.
6. What is the significance of Biot Number?

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7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation
10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]

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12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

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45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.9

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DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

Aim:
To measure emissivity of the test plate surface at various temperature

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:

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The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp

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black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.
Specifications:
1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W

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3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A

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7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300
0

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C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Use proper voltage range on Voltmeter.

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3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.
Tabulation:

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Sl.
No
Voltage

Current

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Black body
temp(
0
C)

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Avg.
temp.

Polished body
temp (

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0
C)
Avg.
temp.

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Enclosure
Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts
4

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? Ta
4
) A
Eb ? E = (W1 ? W2) / ? (Ts
4

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? Ta
4
) A
E = Eb ? {(W1 ? W2) / ? (Ts
4

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? Ta
4
) A}
Where,
W1 = Heater input to black plate = V1 x I1 W

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W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd
2
m
2

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T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)
Eb = Emissivity of black plate = 1

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E = Emissivity of Test plate

47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

? = Stefan boltzman constant = 5.67 x 10

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-8
W/m
2
K
4

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Schematic view of the test set-up:

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Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by
the dimmer stat so that the two plates will be maintained at the same temperature.

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3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

Results:
The emissivity of the test plate surface is found to be _____________.

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Outcome:
From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

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48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Emissivity
2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?
4. State Lambert?s cosine law.

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5. What is the purpose of radiation shield?
6. What is meant by shape factor?
7. Define ? Radiation
8. What is meant by monochromatic emissive power?
9. Define ? Emissive Power

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10. What is meant by absorptivity?
11. Define ? Black Body
12. What is meant by transmissivity?
13. State Plank's distribution law
14. What is meant by gray body?

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15. Define ? Irradiation

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Viva ? voce

49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.10

EFFECTIVENESS OF PARALLEL / COUNTER
FLOW HEAT EXCHANGE

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Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:
(i) Experimental Setup

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(ii) Stop watch
(iii) Thermometer
Theory:
Heat exchangers are classified in three categories:
1. Transfer type

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2. Storage type
3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.
The transfer type exchangers are further classified accordant to flow arrangements as:

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i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water
which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water

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flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:
1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm

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2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50
0

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C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100
0
C - 2 Nos.
7. Measuring flask = 0 ? 1000 CC

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50 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

8. Geyser: single phase type to obtain hot water supply
9. Thermo Cole insulation for outer pipe.

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Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Tabulations:
Sl.

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No.
Flow Hot Fluid (
0
C) Cold Fluid (
0

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C)
Time for
collection of
hot fluid
Kg/sec

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Time for
collection
of cold fluid
Kg/sec
1 Parallel flow

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Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)
1. Area of the pipe A = ? (D ? d) L

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Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube
L = Length of the tube

2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

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51 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Where, m = mass flow rate Kg/ sec.
m = ?v/t, ? = density of water and t = time taken for hot water

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Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet
Tho = Temperature of hot water outlet

3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W

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Where, m = mass flow rate
Cp = Specific heat of capacity
Tco = Temperature of cold water inlet
Tci = Temperature of cold water outlet
4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W

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Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)
?Tm = (?Ti - ?To) / In (?Ti/?To)
Where, ?To = Tho ? Tco
?Ti = Thi ? Tci

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6. Over all heat transfer coefficient
h = Q?/?Tm A W/m
2
K
where Q? = (Qa + Qc) / 2

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Procedure:
1. Place the thermometers in position and note down their readings when they are at room temperature and
no water is flowing at either side. This is required to correct the temperature.
2. Start the flow on hot water side.

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3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.
5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.
6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.
7. Keeping the flow rates same, wait till the steady state conditions are reached.

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8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.
10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Result:
1. The values of effectiveness of heat exchanger were found as
(i) Parallel flow = ________.

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(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)
(i) Parallel flow = ________.
(ii) Counter flow = _________.

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Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow
heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat
exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.
Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.



1. Define ? Heat Exchanger

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2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?
4. Write about the merits of drop wise condensation.
5. What is meant by film wise and drop wise condensation?
6. What is meant by effectiveness?

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7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?
9. Distinguish between regenerator and recuperates.
10. What is meant by parallel flow heat exchanger?
11. What is meant by counter flow heat exchanger?

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12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?
Viva ? voce

53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.11

DETERMINATION OF COP OF A REFRIGERATION
SYSTEM

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Aim:
To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration
system
Apparatus required:

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(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Experimental setup
Description:

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1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a
reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.
2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated
wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a
low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the

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temperature of chilled water. The above unit is located on the trolley behind front panel.
3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic
expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum
strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure
gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high

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pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy
meter to measure the power consumed either by hater or by compressor.

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54 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
A. A compressor condenser unit placed inside trolley and fitted with
1. R-134a reciprocating compressor
2. Condenser
3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan

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4. A receiver with angle check valve
B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity
placed inside a well insulated wooden box and provided with
5. Evaporator coil
6. Stirrer

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7. Electric heater 230 V, A.C.
8. The sensing bulb of low temperature thermostat.
9. A high temperature thermostat.
10. A Thermometer to measure the chilled water temperature
C. The front panel on which are mounted the following

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11. Capillary expansion tube with isolating valve.
12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator
and isolating valve
13. Drier cum strainer and sight glass
14. Thermostat at inlet and outlet of both evaporator and condenser

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15. Pressure gauge at inlet and outlet of evaporator and condenser
16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out
17. Heat power regulator switch and regulator
18. Energy meter to measure the power consumed either by hater or by compressor.

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55 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:

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1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.
2. The heater regulator should be switched off whenever not in use. Heating water beyond 40
0
C may lead to
permanent damage of the entire system. A high temperature cut off thermostat is provided in the water

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chiller, to cut off the heater beyond 30
0
C.Check the setting of the same before operation.
3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.
4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.

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5. The solenoid thermostat is adjusted to cut at 15
0
C and cut in at 10
0
C of the chilled water. Do not alter the

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same.
6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.
7. The space near the condenser should permit good ventilation to aid proper fan performance.
8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked
in

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0
F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,
calibrated in SI units, are not available.)
9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to
obtain the pressure in MN/m

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2
.e.g. P = x psig
= (x + 14.7) psia
= (x + 14.7) / 145 MN/m
2

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(MPa)
10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.
Formulae used:
Let, State 1 indicates the entry of compressor.
State 2 indicates the exit of compressor.

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State 3 indicates the exit from condenser.
State 4 indicates the entry to evaporator
P = Pressure (bar)
T = Temperature (
0

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C)
H = Specific enthalpy (kJ/kg)
v = Specific Volume (m
3
/Kg)

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n = Number of revolutions of energy meter disc.
t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)
t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)
K = Energy meter constant = 3200 lmp / kWh
N = Speed of compressor = 2840 rpm

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h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

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h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2

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h3 = Specific enthalpy at Pc and T3 (kJ/kg)
h4 = h3
Stroke volume of compressor = (?/ 4) d
2
l = 12.58 x 10

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-6
m
3

1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar

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2. Average condenser pressure, Pc = (P2 + P3) / 2 bar
3. Heater input, Qe = (n / t1) x (3600 / k) kW
4. Compressor input, W = (n / t2) x (3600 / k) kW
5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1
6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)

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7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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57 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I


Sl.
No.

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Initial
Temp.
of water

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Final
Temp.
of water
Duration
of exp.

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Delivery
pressure

Delivery

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Temp.

Condense
Outlet
Pressure

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Condense
Outlet
Temp.

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Pressure
after
throttling

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Temp.

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After
Throttli
ng

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Suction
pressur
e
Suction
Temp.

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Time for

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10 rev. of
compress
or energy
meter

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Height
of water
in the

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vessel

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58 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
Load Test with Capillary tube as expansion device:

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1. Fill the chilled water calorimeter with pure water so that the evaporative coils are
fully immersed.
2. Select the capillary tube line by opening the shut-off valve on this line and closing
the one on the thermostatic expansion valve line. The solenoid switch is switched OFF.
3. Start the compressor and run for some time so that the chilled water temperature

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is lowered to the given test temperature.
4. Switch on the heater and slowly increase the power.
5. Allow The temperature in water calorimeter to reach the equilibrium
temperature.
6. Connect energy meter to motor and heater by the selector switch one after another

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and note down the time taken for 10 pulses of the energy meter disc.
7. Note down the pressure and temperature readings at locations 1,2,3 & 4 as
mentioned.
8. Switch OFF the heater and the mains.
Result:

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The load test on a refrigeration test rig was conducted and the results are as follows.
1. Actual C.O.P. of the system =____________.
2. Rhetorical C.O.P. of the system = ___________.
3. Volumetric Efficiency = ___________.

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Outcome:
From this experiment, conducting the load test on a refrigeration test rig and finding out the
volumetric efficiency and co-efficient of performance for any type of refrigerant is learnt and this experiment
could be used in the areas such as Refrigerator and Air Conditioning.
Applications:

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Refrigerator, Air Conditioning.

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59 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? COP

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2. Which thermodynamic cycle is used in air conditioning of airplanes using air as refrigerant?
3. Define ? Ton of Refrigeration
4. What is meant by refrigeration?
5. What is meant by air conditioning?
6. What are the four important properties of a good refrigerant?

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7. How does the actual vapour compression cycle differ from that of the ideal cycle?
8. Name any four commonly used refrigerants.
9. What are the expansion devices used in a vapour compression plant?
10. Why throttle valve is used in place of expansion cylinder for vapour compression refrigerant machine?
11. What are the merits of air refrigeration system?

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12. What are the demerits of air refrigeration system?
13. Define ? Refrigerant
14. What is net refrigerating effect of the refrigerant?
15. What are the methods to obtain sub cooling of refrigerant?

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Viva ? voce

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60 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.12 EXPERIMENTS ON PSYCHROMETRIC PROCESS

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Aim:
To conduct an experiment on psychrometric processes with air conditioning system
Apparatus required:
(i) Thermometer

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(ii) Electric Heater
(iii) Stop watch
(iv) Digital anemometer
(v) Experimental setup
Description:

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The test rig consist of
1. An air duct support of stand
2. A blower to set up air flow through the duct along with a speed control to vary the
velocity of air.
3. A heater to rise the air temperature with regulator and energy meter.

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4. Water spray, collecting tray, reservoir with gauge pump.
5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.
(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after cooling coil).
6. The test rig consist of compressor, condenser unit placed inside trolley and fitted
with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for

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condenser and (iv) Liquid receiver.
7. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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61 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I

Precautions:
1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence
avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kw only for the motor

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circuit.
2. Natural air currents in the room if in the direction of air duct may defect the experimental results and
hence the duct should be placed such that no wind from doors, windows, fan and cooling air from
other test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan
and should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase

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beyond 240 psi.
3. Never exceed dry bulb temperatures of 40
0
C after the heater (station 2) otherwise the air duct may be
damaged.

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4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may
exceed its maximum of 32
0
C and calibration may be affected.
5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not

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running this will lead to rise in temperature at the heater and may damage the heater and the air duct.
6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their
duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.
7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer
is placed inside the reservoir at the top. This may have to the cleaned when necessary.

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8. Do not open the gate valve fully otherwise water may be splashed outside and the waster
measurement may be in error.
S.
N
o

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Inlet temp
Outlet
temp
Pressu
re

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P1
Tem
p.
T1
Pressu

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re
P2
Temp.
T2
Pressu

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re
P3

Tem
p.

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T3


Pressu
re

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P4


Temp.
T4

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Energy
for 10
revolutio
ns
Twet Tdry Twet Tdry Lb/in

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o
C Lb/in
o
C Lb/in
o

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C Lb/in
o
C

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62 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

9. If the low pressure cut out comes in to action, it means that the Freon charge is insufficient and may
have to be filled up. The suction pressure should never go below 2 psi as otherwise the compressor
seals will be damaged and air and moisture may enter the system.

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10. The refrigerant strainer placed on the front panel should always be warm. If it cools and moisture
condenser on it, then the strainer might have to be charged by an experienced refrigeration
mechanics.
11. The refrigerating system can work continuously for 2 hours, however if the room temperature is above
25

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0
C the condenser may be heated up and the delivery pressure may rise. Do not exceed 240 psi.
Pour one or two glasses of drinking water over the fins of the condenser in order to reduce the
delivery pressure.
12. After some months of operation the compressor may have to be topped up with oil and some quantity

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of Freon-22 may have to be charged by an experienced mechanics.
13. See that distilled water is filled up in the plastic dishes provided under the wet bulb thermometers and
that the wicks are in tact otherwise erroneous readings may be obtained. These thermometers will
show correct readings only when the fan is in operation.
14. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and

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corrosion damage.

Formulae used:
1. Corresponding to the dry and wet bulb temperature at all the stations obtain the specific enthalpy and
specific humidity values from psychrometric chart.

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i.e., h1 and w1 at tb1 and tw1 and so on.
2. Air flow rate, ma = (A x V) / v4 Kg / sec
Where, A = Area of duct at outlet in m
2
(0.46 m x 0.086 m)

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V = Air velocity ( m / sec)
V4 = Specific volume of moist air at station 4 using psychometric chart m
3
/Kg
3. Moisture added from psychrometric chart, mw1 = ma (w3-w2) Kg / sec.

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Where, w3 = Specific humidity at station 3
w2 = Specific humidity at station 2
4. Cooling effect produced on air, Qe = ma (h3 ? h4) kW.
Where, h3 = Specific enthalpy at state 3 kJ/kg
h4 = Specific enthalpy at state 4 kJ/kg

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5. Moisture condensed, mcl = ma (w3 ? w4) kg/sec
Where, w3 = Specific humidity at station 3
w4 = Specific humidity at station 4

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Procedure:
1. Fill water in the wet bulb temperature probe trays.
2. Start the main.
3. Start the blower and run it the required speed by keeping the speed regulator at

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position.
4. Start the spray pump and open the gate valve suitably.
5. Start the heater.
6. Select the expansion device (Capillary tube / Thermostatic expansion valve)
7. Start the cooling compressor.

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8. Wait for some time till thermometers shown practically constant readings and note down the
following readings:
(i) Dry bulb temperatures tdb1, tdb2, tdb3, tdb4.
(ii) Wet bulb temperatures twb1, twb2, twb3, twb4.
(iii) Spray water temperature, ts

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(iv) Surface temperature of cooler, tm ( at control panel)
(v) Pressure gauge reading, pd ( at control panel)
(vi) Compound gauge reading, Ps ( at control panel)
(vii) Level reduction?l? in spray reservoir (mm) during 5 min.
(viii) Amount of condensate collected ?lc?, in a measuring jar at cooler tray during a

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run of 5 minutes at constant conditions.
(ix) Time in second ?SH? for 10 pulses of the energy meter disc connected to the
heater.
(x) Time in seconds Sc for 10 pulses of the energy meter disc connected to cooler
compressor.

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Result:
Experiment on psychrometric processes with air conditioning system was drawn
Outcome:
From this experiment, conducting the test on psychrometric processes with air
conditioning system is learnt and this experiment could be used in all types of air conditioning systems.

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Applications:
Air Conditioning.

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64 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the commonly used unit of refrigeration?
2. Distinguish between summer air conditioning and winter air conditioning.
3. Define ? RSHF Line
4. Define ? By Pass Factor of a Heating Coil
5. What is the effect of sub cooling a refrigerant in a vapour compression cycle?

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6. What is the function of analyzer and rectifier in an absorption system?
7. What is the purpose of generator assembly in vapour absorption refrigeration system?
8. State the substance used in the Lithium Bromide system and their functions.
9. Differentiate wet compression from dry compression.
10. Define ? Apparatus Dew Point

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11. What is meant by dew point temperature?
12. Define ? Wet Bulb Temperature
13. Define ? Degree of Saturation
14. What is meant by specific humidity?
15. Define ? Relative Humidity

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Viva ? voce

65 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.13

PERFORMANCE TEST ON A RECIPROCATING
AIR COMPRESSOR

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Aim:
To conduct a load test on the 2 - stage reciprocating air compressor to determine the isothermal and
volumetric Efficiencies at various delivery pressures

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Apparatus required:
* Air compressor with accessories.
* Stop watch.
Description:
Two stage air compressors is a reciprocating type driven by a prime mover. The test rig consist of a base on

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which the tank is mounted. The outlet of the compressor is connected to the receiver. The suction is
connected to air tank with a calibrated orifice plate through a water manometer. The input to the motor is
recorded by an energy meter. The temperature and pressure of the air compressed is indicated by a
thermometer and pressure gauge.
Specifications:

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1. Air compressor:
* LP Bore, DLP = 63.0 mm.
* HP Bore, DHP = 79.0 mm.
* Stroke, L = 80.0 mm.
* Speed, N = 1440 rpm (5 HP)

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* Effective radius = 0.193 m
2. Air receiver capacity = 0.33 m3
3. Orifice, diameter, d0 = 12 mm
4. Orifice area,. A0 : ?d0
2

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/ 4 = ----------- m
2

5. Coefficient of discharge C d. = 0.6
6. Energy-meter constant = 200 rev / kWh

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66 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

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Observation Table: II
Sl.
No.
Actual
Discharge

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Va
Theoritical
Discharge
Vt
Volumetric

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Efficiency
?
Power
Input

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Output
Power

Overall
Efficiency

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?0
Isothermal
Workdone
IwD
Polytropic

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Workdone
PwD
Isothermal
Efficiency
?iso

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m
3
/sec m
3
/sec % kW kW % J/Kg J/Kg %

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Sl.
No.
Pressure

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p
Manometer
h1
Manometer
h2

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Time for 5 revolutions Energy meter Speed of the compressor Temperature
T1
Temperature
T1
Kg/cm

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2
Cm cm sec rpm
o
C
o

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C


FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart

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and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION

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VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence

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To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design

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products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies

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5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering

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2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools

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6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms

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9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder

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4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant

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9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system

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12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection

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experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.

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12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC

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Boiler.



COURSE OBJECTIVES

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COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS

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1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11

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3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21

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5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31

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7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47

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CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14

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Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate

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method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters

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together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples

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No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2

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(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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9 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help

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of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:

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1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm

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6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100

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0
C
9. Maximum temperature of the hot plate = 170
0
C

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10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V

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15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0

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C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:
Sl. No. Voltmeter
V

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Ammeter
A
Main heater (
0
C) Test Plate (

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0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:

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1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single

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phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.

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8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.

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3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?

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8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?

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13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?

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18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:

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To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple

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(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.

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There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.

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4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.

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4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging

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k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:

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Sl.
No.
Voltage
(V)
Current

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(A)
Heater Temperature
(
0
C)

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Asbestos Temperature
(
0
C)
Saw dust

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Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos

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layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:

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The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)

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6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?

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11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.

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16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical

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tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which

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in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.

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The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Schematic view of the test set-up:

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mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch

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Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples

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6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}

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Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W

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Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L
3

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?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v
2

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is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid

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v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity

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?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.

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hL / k = 0.56 (Gr.Pr)
0.25
for 10
4
< Gr.Pr.<10

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8

hL / k = 0.13 (Gr.Pr)
1/3
for 10

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8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).

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3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:

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The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m

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2
K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing

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heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?

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5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)

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10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness

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15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?

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20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:

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To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer

Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air

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stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of

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orifice meter and the water manometer fitted on the board.


24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

Sl. No. Voltage Current Temperature in (

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0
C)
Manometer
reading of water
in h in meter

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(V) (A)
T1

T2

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T3

T4

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T5

T6

h1

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cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor

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5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0
C

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(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:

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1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.

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6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.

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2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. The rate at which air is getting heated is calculated as

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qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o

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C)
= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate

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Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m
3
/hr

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3. ha = qa /A(Ts- Ta) W / m
2
K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m

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2

Ta = Average temperature of air = (T1 + T6)/2
o
C

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Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C
Cd = 0.64
H = Difference of water level in manometer m

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?w Density of water = 1000 Kg/m
3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

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d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

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using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2

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)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o
C

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5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

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27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k

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? = Viscosity Ns/m
2

k = Thermal conductivity of fluid W/m
2

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K
Nu = 0.023 (Re)
0.8
(Pr)
0.4

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Bulk mean temperature = (T1 + T6)/2

Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.

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hactual = -------------- W/m
2
K
htheoritical = -------------- W/m
2

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K

Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?

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3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?

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8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection

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13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

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Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,

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the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure

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temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat

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flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm

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2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.

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2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

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30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature

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gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:

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Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R

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Tabulation:
Sl.No. Voltmeter
reading
(V)
Ammeter

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reading
(A)
T1
(
0

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C)
T2
(
0
C)

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T3
(
0
C)
T4

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(
0
C)
T5
(

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0
C)
T6
(
0

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C)
T7
(
0
C)

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T8
(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Composite wall apparatus set-up

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Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W

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c. Asbestos section = ------------W

Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure

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Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?

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5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.

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9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

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33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

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DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

Aim:
To find out the thermal conductivity of insulating powder by conduction

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Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A

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multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

Procedure:

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1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.

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5. Repeat the experiments for different power inputs.


The readings are tabulated below

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Sl.No. Voltmeter
reading( V)
Ammeter
reading (A)
T1

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(
0
C)
T2
(

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0
C)
T3
(
0

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C)
T4
(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm

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The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Fig. 1 Apparatus of thermal conductivity of insulating powder

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[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

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Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam

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boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity

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3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.

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8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?

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13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?

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18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

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HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

Aim:

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To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is

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measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:
Sl.

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No.
V I

Fin Temperatures (
0

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C)
Ambient Temp
(
0
C)

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Manometer
Reading
(V)

(A)

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T1 T2 T3 T4 T5 T6 T7 T8
h1
cm
h2

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cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Duct size = 150 mm x 100 mm.

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2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

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Schematic view of the test set-up:



zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5

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10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C
12. Temperature indicator = 0 ? 300

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0
C
(With compensation of ambient temperature up-to 50
0
C)

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13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8

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Brass Pin Fin
Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.

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4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:

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Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.

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4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2

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Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m

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3
/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m

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3

?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s

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2

Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s

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Where Q = discharge of air

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A = area of the duct

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4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.

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(T1 + T6) / 2
o
C
5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number

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6. Nusselt Number:
Nu = CRe
m
(Pr)
0.33

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7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk
m= ?(hp/kA)

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A = area of fin = (? x D
2
) /4
L = Length of the fin
Tw ? average temperature

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T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________

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Heat transfer, Q = ___________ W

Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.


40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer

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6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?

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11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.8

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DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

Aim:

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To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch

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(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water

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between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.

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When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere

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3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg

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8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C
= (or) 0.1 Kcal / kg
0

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C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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11. Temperature indicator digital 0.1
0
C L.C 0 - 200
0

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C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water
Precautions:

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Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4

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? Td
4
)
Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)

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Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

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43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulations:
Proc
edur

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e:
1. H
eat the
water
in the

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tank by
the immersion heater up to a temperature of about 90
0
C.
2. Remove the disc, D before pouring the hot water in the jacket.

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3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.

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6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m

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2
k
4
.

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Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using

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boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

Sl. No.

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Hemisphere Temperature(
0
C) Avg. Temp.
of the
Hemisphere

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(Th)
T4
Steady
Temp. of
Disc

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T0 (Td)
Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number
5. State Wien?s displacement law.

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6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation
10. What are the various modes of condensation?

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11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.9

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DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

Aim:

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To measure emissivity of the test plate surface at various temperature
Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The

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temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.
Specifications:
1. Heater input to black plate W1 = V1 x I1 W

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2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V

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6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300

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0
C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.

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Tabulation:
Sl.
No
Voltage

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Current

Black body
temp(
0

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C)
Avg.
temp.

Polished body

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temp (
0
C)
Avg.
temp.

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Enclosure
Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts

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4
? Ta
4
) A
Eb ? E = (W1 ? W2) / ? (Ts

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4
? Ta
4
) A
E = Eb ? {(W1 ? W2) / ? (Ts

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4
? Ta
4
) A}
Where,

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W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd
2
m

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2

T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)

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Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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? = Stefan boltzman constant = 5.67 x 10
-8
W/m
2
K

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4


Schematic view of the test set-up:

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Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by

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the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

Results:

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The emissivity of the test plate surface is found to be _____________.
Outcome:
From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

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48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Emissivity
2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?

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4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?
6. What is meant by shape factor?
7. Define ? Radiation
8. What is meant by monochromatic emissive power?

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9. Define ? Emissive Power
10. What is meant by absorptivity?
11. Define ? Black Body
12. What is meant by transmissivity?
13. State Plank's distribution law

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14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

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49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.10

EFFECTIVENESS OF PARALLEL / COUNTER

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FLOW HEAT EXCHANGE

Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:

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(i) Experimental Setup
(ii) Stop watch
(iii) Thermometer
Theory:
Heat exchangers are classified in three categories:

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1. Transfer type
2. Storage type
3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.

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The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water

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which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:

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1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50

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0
C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100
0
C - 2 Nos.

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7. Measuring flask = 0 ? 1000 CC

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8. Geyser: single phase type to obtain hot water supply

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9. Thermo Cole insulation for outer pipe.
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Tabulations:

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Sl.
No.
Flow Hot Fluid (
0
C) Cold Fluid (

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0
C)
Time for
collection of
hot fluid

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Kg/sec
Time for
collection
of cold fluid
Kg/sec

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1 Parallel flow
Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)

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1. Area of the pipe A = ? (D ? d) L
Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube
L = Length of the tube

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2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

51 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Where, m = mass flow rate Kg/ sec.

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m = ?v/t, ? = density of water and t = time taken for hot water
Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet
Tho = Temperature of hot water outlet

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3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W
Where, m = mass flow rate
Cp = Specific heat of capacity
Tco = Temperature of cold water inlet
Tci = Temperature of cold water outlet

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4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W
Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)
?Tm = (?Ti - ?To) / In (?Ti/?To)
Where, ?To = Tho ? Tco

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?Ti = Thi ? Tci
6. Over all heat transfer coefficient
h = Q?/?Tm A W/m
2
K

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where Q? = (Qa + Qc) / 2

Procedure:
1. Place the thermometers in position and note down their readings when they are at room temperature and
no water is flowing at either side. This is required to correct the temperature.

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2. Start the flow on hot water side.
3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.
5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.
6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.

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7. Keeping the flow rates same, wait till the steady state conditions are reached.
8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.
10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

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52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Result:
1. The values of effectiveness of heat exchanger were found as

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(i) Parallel flow = ________.
(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)
(i) Parallel flow = ________.
(ii) Counter flow = _________.

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Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow
heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat
exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Heat Exchanger
2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?
4. Write about the merits of drop wise condensation.
5. What is meant by film wise and drop wise condensation?

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6. What is meant by effectiveness?
7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?
9. Distinguish between regenerator and recuperates.
10. What is meant by parallel flow heat exchanger?

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11. What is meant by counter flow heat exchanger?
12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?
Viva ? voce

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53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.11

DETERMINATION OF COP OF A REFRIGERATION

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SYSTEM

Aim:
To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration
system

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Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Experimental setup

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Description:
1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a
reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.
2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated
wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a

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low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the
temperature of chilled water. The above unit is located on the trolley behind front panel.
3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic
expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum
strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure

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gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high
pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy
meter to measure the power consumed either by hater or by compressor.

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54 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
A. A compressor condenser unit placed inside trolley and fitted with
1. R-134a reciprocating compressor
2. Condenser

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3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan
4. A receiver with angle check valve
B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity
placed inside a well insulated wooden box and provided with
5. Evaporator coil

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6. Stirrer
7. Electric heater 230 V, A.C.
8. The sensing bulb of low temperature thermostat.
9. A high temperature thermostat.
10. A Thermometer to measure the chilled water temperature

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C. The front panel on which are mounted the following
11. Capillary expansion tube with isolating valve.
12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator
and isolating valve
13. Drier cum strainer and sight glass

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14. Thermostat at inlet and outlet of both evaporator and condenser
15. Pressure gauge at inlet and outlet of evaporator and condenser
16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out
17. Heat power regulator switch and regulator
18. Energy meter to measure the power consumed either by hater or by compressor.

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55 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.
2. The heater regulator should be switched off whenever not in use. Heating water beyond 40
0
C may lead to

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permanent damage of the entire system. A high temperature cut off thermostat is provided in the water
chiller, to cut off the heater beyond 30
0
C.Check the setting of the same before operation.
3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.

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4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.
5. The solenoid thermostat is adjusted to cut at 15
0
C and cut in at 10
0

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C of the chilled water. Do not alter the
same.
6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.
7. The space near the condenser should permit good ventilation to aid proper fan performance.
8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked

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in
0
F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,
calibrated in SI units, are not available.)
9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to

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obtain the pressure in MN/m
2
.e.g. P = x psig
= (x + 14.7) psia
= (x + 14.7) / 145 MN/m

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2
(MPa)
10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.
Formulae used:
Let, State 1 indicates the entry of compressor.

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State 2 indicates the exit of compressor.
State 3 indicates the exit from condenser.
State 4 indicates the entry to evaporator
P = Pressure (bar)
T = Temperature (

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0
C)
H = Specific enthalpy (kJ/kg)
v = Specific Volume (m
3

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/Kg)
n = Number of revolutions of energy meter disc.
t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)
t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)
K = Energy meter constant = 3200 lmp / kWh

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N = Speed of compressor = 2840 rpm
h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

56 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2
h3 = Specific enthalpy at Pc and T3 (kJ/kg)
h4 = h3
Stroke volume of compressor = (?/ 4) d
2

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l = 12.58 x 10
-6
m
3

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1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar
2. Average condenser pressure, Pc = (P2 + P3) / 2 bar
3. Heater input, Qe = (n / t1) x (3600 / k) kW
4. Compressor input, W = (n / t2) x (3600 / k) kW
5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1

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6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)
7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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57 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I


Sl.

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No.

Initial
Temp.
of water

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Final
Temp.
of water
Duration

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of exp.

Delivery
pressure

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Delivery
Temp.

Condense
Outlet

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Pressure

Condense
Outlet
Temp.

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Pressure
after
throttling

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Temp.
After
Throttli
ng

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Suction
pressur
e
Suction

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Temp.

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Time for
10 rev. of
compress
or energy
meter

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Height
of water

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in the
vessel

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58 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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Load Test with Capillary tube as expansion device:
1. Fill the chilled water calorimeter with pure water so that the evaporative coils are
fully immersed.
2. Select the capillary tube line by opening the shut-off valve on this line and closing
the one on the thermostatic expansion valve line. The solenoid switch is switched OFF.

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3. Start the compressor and run for some time so that the chilled water temperature
is lowered to the given test temperature.
4. Switch on the heater and slowly increase the power.
5. Allow The temperature in water calorimeter to reach the equilibrium
temperature.

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6. Connect energy meter to motor and heater by the selector switch one after another
and note down the time taken for 10 pulses of the energy meter disc.
7. Note down the pressure and temperature readings at locations 1,2,3 & 4 as
mentioned.
8. Switch OFF the heater and the mains.

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Result:
The load test on a refrigeration test rig was conducted and the results are as follows.
1. Actual C.O.P. of the system =____________.
2. Rhetorical C.O.P. of the system = ___________.
3. Volumetric Efficiency = ___________.

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Outcome:
From this experiment, conducting the load test on a refrigeration test rig and finding out the
volumetric efficiency and co-efficient of performance for any type of refrigerant is learnt and this experiment
could be used in the areas such as Refrigerator and Air Conditioning.

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Applications:
Refrigerator, Air Conditioning.

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59 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? COP
2. Which thermodynamic cycle is used in air conditioning of airplanes using air as refrigerant?
3. Define ? Ton of Refrigeration
4. What is meant by refrigeration?
5. What is meant by air conditioning?

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6. What are the four important properties of a good refrigerant?
7. How does the actual vapour compression cycle differ from that of the ideal cycle?
8. Name any four commonly used refrigerants.
9. What are the expansion devices used in a vapour compression plant?
10. Why throttle valve is used in place of expansion cylinder for vapour compression refrigerant machine?

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11. What are the merits of air refrigeration system?
12. What are the demerits of air refrigeration system?
13. Define ? Refrigerant
14. What is net refrigerating effect of the refrigerant?
15. What are the methods to obtain sub cooling of refrigerant?

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Viva ? voce

60 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.12 EXPERIMENTS ON PSYCHROMETRIC PROCESS

Aim:
To conduct an experiment on psychrometric processes with air conditioning system
Apparatus required:

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(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Digital anemometer
(v) Experimental setup

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Description:
The test rig consist of
1. An air duct support of stand
2. A blower to set up air flow through the duct along with a speed control to vary the
velocity of air.

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3. A heater to rise the air temperature with regulator and energy meter.
4. Water spray, collecting tray, reservoir with gauge pump.
5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.
(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after cooling coil).
6. The test rig consist of compressor, condenser unit placed inside trolley and fitted

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with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for
condenser and (iv) Liquid receiver.
7. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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61 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I

Precautions:
1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence

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avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kw only for the motor
circuit.
2. Natural air currents in the room if in the direction of air duct may defect the experimental results and
hence the duct should be placed such that no wind from doors, windows, fan and cooling air from
other test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan

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and should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase
beyond 240 psi.
3. Never exceed dry bulb temperatures of 40
0
C after the heater (station 2) otherwise the air duct may be

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damaged.
4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may
exceed its maximum of 32
0
C and calibration may be affected.

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5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not
running this will lead to rise in temperature at the heater and may damage the heater and the air duct.
6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their
duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.
7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer

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is placed inside the reservoir at the top. This may have to the cleaned when necessary.
8. Do not open the gate valve fully otherwise water may be splashed outside and the waster
measurement may be in error.
S.
N

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o
Inlet temp
Outlet
temp
Pressu

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re
P1
Tem
p.
T1

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Pressu
re
P2
Temp.
T2

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Pressu
re
P3

Tem

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p.
T3


Pressu

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re
P4


Temp.

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T4
Energy
for 10
revolutio
ns

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Twet Tdry Twet Tdry Lb/in
o
C Lb/in
o
C Lb/in

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o
C Lb/in
o
C

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62 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

9. If the low pressure cut out comes in to action, it means that the Freon charge is insufficient and may
have to be filled up. The suction pressure should never go below 2 psi as otherwise the compressor

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seals will be damaged and air and moisture may enter the system.
10. The refrigerant strainer placed on the front panel should always be warm. If it cools and moisture
condenser on it, then the strainer might have to be charged by an experienced refrigeration
mechanics.
11. The refrigerating system can work continuously for 2 hours, however if the room temperature is above

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25
0
C the condenser may be heated up and the delivery pressure may rise. Do not exceed 240 psi.
Pour one or two glasses of drinking water over the fins of the condenser in order to reduce the
delivery pressure.

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12. After some months of operation the compressor may have to be topped up with oil and some quantity
of Freon-22 may have to be charged by an experienced mechanics.
13. See that distilled water is filled up in the plastic dishes provided under the wet bulb thermometers and
that the wicks are in tact otherwise erroneous readings may be obtained. These thermometers will
show correct readings only when the fan is in operation.

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14. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

Formulae used:
1. Corresponding to the dry and wet bulb temperature at all the stations obtain the specific enthalpy and

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specific humidity values from psychrometric chart.
i.e., h1 and w1 at tb1 and tw1 and so on.
2. Air flow rate, ma = (A x V) / v4 Kg / sec
Where, A = Area of duct at outlet in m
2

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(0.46 m x 0.086 m)
V = Air velocity ( m / sec)
V4 = Specific volume of moist air at station 4 using psychometric chart m
3
/Kg

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3. Moisture added from psychrometric chart, mw1 = ma (w3-w2) Kg / sec.
Where, w3 = Specific humidity at station 3
w2 = Specific humidity at station 2
4. Cooling effect produced on air, Qe = ma (h3 ? h4) kW.
Where, h3 = Specific enthalpy at state 3 kJ/kg

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h4 = Specific enthalpy at state 4 kJ/kg
5. Moisture condensed, mcl = ma (w3 ? w4) kg/sec
Where, w3 = Specific humidity at station 3
w4 = Specific humidity at station 4

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63 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Fill water in the wet bulb temperature probe trays.
2. Start the main.

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3. Start the blower and run it the required speed by keeping the speed regulator at
position.
4. Start the spray pump and open the gate valve suitably.
5. Start the heater.
6. Select the expansion device (Capillary tube / Thermostatic expansion valve)

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7. Start the cooling compressor.
8. Wait for some time till thermometers shown practically constant readings and note down the
following readings:
(i) Dry bulb temperatures tdb1, tdb2, tdb3, tdb4.
(ii) Wet bulb temperatures twb1, twb2, twb3, twb4.

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(iii) Spray water temperature, ts
(iv) Surface temperature of cooler, tm ( at control panel)
(v) Pressure gauge reading, pd ( at control panel)
(vi) Compound gauge reading, Ps ( at control panel)
(vii) Level reduction?l? in spray reservoir (mm) during 5 min.

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(viii) Amount of condensate collected ?lc?, in a measuring jar at cooler tray during a
run of 5 minutes at constant conditions.
(ix) Time in second ?SH? for 10 pulses of the energy meter disc connected to the
heater.
(x) Time in seconds Sc for 10 pulses of the energy meter disc connected to cooler

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compressor.
Result:
Experiment on psychrometric processes with air conditioning system was drawn
Outcome:
From this experiment, conducting the test on psychrometric processes with air

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conditioning system is learnt and this experiment could be used in all types of air conditioning systems.

Applications:
Air Conditioning.

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64 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the commonly used unit of refrigeration?
2. Distinguish between summer air conditioning and winter air conditioning.
3. Define ? RSHF Line
4. Define ? By Pass Factor of a Heating Coil

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5. What is the effect of sub cooling a refrigerant in a vapour compression cycle?
6. What is the function of analyzer and rectifier in an absorption system?
7. What is the purpose of generator assembly in vapour absorption refrigeration system?
8. State the substance used in the Lithium Bromide system and their functions.
9. Differentiate wet compression from dry compression.

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10. Define ? Apparatus Dew Point
11. What is meant by dew point temperature?
12. Define ? Wet Bulb Temperature
13. Define ? Degree of Saturation
14. What is meant by specific humidity?

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15. Define ? Relative Humidity

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Viva ? voce

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65 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.13

PERFORMANCE TEST ON A RECIPROCATING

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AIR COMPRESSOR

Aim:
To conduct a load test on the 2 - stage reciprocating air compressor to determine the isothermal and
volumetric Efficiencies at various delivery pressures

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Apparatus required:
* Air compressor with accessories.
* Stop watch.
Description:

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Two stage air compressors is a reciprocating type driven by a prime mover. The test rig consist of a base on
which the tank is mounted. The outlet of the compressor is connected to the receiver. The suction is
connected to air tank with a calibrated orifice plate through a water manometer. The input to the motor is
recorded by an energy meter. The temperature and pressure of the air compressed is indicated by a
thermometer and pressure gauge.

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Specifications:
1. Air compressor:
* LP Bore, DLP = 63.0 mm.
* HP Bore, DHP = 79.0 mm.
* Stroke, L = 80.0 mm.

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* Speed, N = 1440 rpm (5 HP)
* Effective radius = 0.193 m
2. Air receiver capacity = 0.33 m3
3. Orifice, diameter, d0 = 12 mm
4. Orifice area,. A0 : ?d0

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2
/ 4 = ----------- m
2

5. Coefficient of discharge C d. = 0.6

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6. Energy-meter constant = 200 rev / kWh

66 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

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Observation Table: II
Sl.
No.
Actual

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Discharge
Va
Theoritical
Discharge
Vt

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Volumetric
Efficiency
?
Power
Input

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Output
Power

Overall

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Efficiency
?0
Isothermal
Workdone
IwD

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Polytropic
Workdone
PwD
Isothermal
Efficiency

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?iso
m
3
/sec m
3

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/sec % kW kW % J/Kg J/Kg %


Sl.
No.

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Pressure
p
Manometer
h1
Manometer

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h2
Time for 5 revolutions Energy meter Speed of the compressor Temperature
T1
Temperature
T1

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Kg/cm
2
Cm cm sec rpm
o
C

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o
C

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67 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Check whether manometer is filled with water up to the required level.
2. The maximum pressure in the receiver tank should not exceed 12 kg / cm

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2

Procedure:
1. Ensure that gauge pressure in the tank is zero.
2. Start the compressor. Read the receiver pressure gauge for a particular pressure.

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3. Maintain the pressure constant by adjusting the outlet valve.
4. Note down the manometer reading and time taken for 3 revolution of the energy
Formulae used:
1. Density of air at RTP:
? RTP = ? NTP X 273 Kg/ m

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3

(273 + Room Temp)
Where density of air at NTP = 1.293 Kg/ m
3

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.

2. Air head causing flow:
ha RTP = (h1 - h2) x ? water m
?a RTP

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Where,
(h1- h2) = Difference in manometer liquid, in m.

3. Actual volume at RTP:
Va RTP = C.d x Ao x ? 2 g ha RTP

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Where,
C d= Coefficient of discharge = 0.6.
A o = Area of orifice = ?(d0)
2
m

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2
.
4
Diameter of orifice d o = 0.01 m.
4. Actual volume at NTP:

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Va NTP = VaRTP x T NTP
T RTP
Where,
T NTP = Normal temp - 273
o

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k
T RTP = Room temp -
o
c (273 + TROOM )
FirstRanker.com - FirstRanker's Choice

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1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL

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2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

--- Content provided by FirstRanker.com ---

? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels

--- Content provided by FirstRanker.com ---

? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION

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MISSION
VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals

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2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which

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enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt

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and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able

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1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution

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5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both

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verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus

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3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)

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8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:

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11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus

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3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction

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7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-

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efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.

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15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.

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CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus

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11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15

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4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6

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Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43

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10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63

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14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75

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PROJECT WORK 81

8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:

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To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in

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which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.

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Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d

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2
(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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9 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.

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4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

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Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm

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5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0

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C ? 100
0
C
9. Maximum temperature of the hot plate = 170
0

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C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V

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14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200

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0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter

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V
Ammeter
A
Main heater (
0

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C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.

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3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.

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7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be

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k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat

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exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity

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2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?

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7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.

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12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.

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17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

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Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus

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(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is

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transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside

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an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm

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3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.

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3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)

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Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found

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Tabulation:
Sl.
No.
Voltage
(V)

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Current
(A)
Heater Temperature
(
0

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C)
Asbestos Temperature
(
0
C)

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Saw dust
Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.

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5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.

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Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?

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5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?

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10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow

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15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.

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20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:

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To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of

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the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

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When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Schematic view of the test set-up:
mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm

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4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel

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thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0

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c)

V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Heat transfer coefficient is given by

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h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m

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2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C

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q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L

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3
?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v

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2
is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface

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K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid

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G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K

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-1

Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been

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determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25
for 10
4

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< Gr.Pr.<10
8

hL / k = 0.13 (Gr.Pr)
1/3

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for 10
8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.

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2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

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Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K

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Experimental = ______________ W/ m
2
K

Outcomes:

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From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.

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4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.

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9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?

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14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness

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19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

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Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer

Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band

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heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to

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measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.


24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

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Sl. No. Voltage Current Temperature in (
0
C)
Manometer
reading of water

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in h in meter

(V) (A)
T1

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T2

T3

T4

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T5

T6

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h1
cm
h2
cm

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm

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4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0

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C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.

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5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference

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in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.

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4. Note down the heater input.

26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:

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1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (

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o
C)
= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr

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Q = Volume flow rate
Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m
3

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/hr
3. ha = qa /A(Ts- Ta) W / m
2
K
qa = Rate of which air is getting heated.

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A = Test section area = ? x Di x L m
2

Ta = Average temperature of air = (T1 + T6)/2
o

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C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C
Cd = 0.64

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H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m

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3

d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

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using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di

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2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o

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C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings

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6. Prandtl Number:

27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k

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Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

k = Thermal conductivity of fluid W/m

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2
K
Nu = 0.023 (Re)
0.8
(Pr)

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0.4
Bulk mean temperature = (T1 + T6)/2

Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection

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apparatus.
hactual = -------------- W/m
2
K
htheoritical = -------------- W/m

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2
K

Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection

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apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is meant by boiling and condensation?

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2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?

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7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?

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12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:

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When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly

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temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The

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apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:

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1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:

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1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.

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5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)

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6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.

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Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities

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Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter
reading
(V)

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Ammeter
reading
(A)
T1
(

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0
C)
T2
(
0

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C)
T3
(
0
C)

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T4
(
0
C)
T5

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(
0
C)
T6
(

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0
C)
T7
(
0

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C)
T8
(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W

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b. Wood section = ---------------W
c. Asbestos section = ------------W

Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt

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and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.

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4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.

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8. Explain the significance of Fourier number.
9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

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DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

Aim:

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To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and

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T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

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Procedure:

1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.

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4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.


The readings are tabulated below

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Sl.No. Voltmeter
reading( V)
Ammeter
reading (A)

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T1
(
0
C)
T2

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(
0
C)
T3
(

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0
C)
T4
(
0

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C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm

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The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Fig. 1 Apparatus of thermal conductivity of insulating powder

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[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

Result:

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The thermal conductivity of insulating powder by conduction is found and the result is, ___________

Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is

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analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is the need for conducting this experiment?

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2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.

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7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?

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12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?

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17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.7

HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

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Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer
Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the

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fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:

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Sl.
No.
V I

Fin Temperatures (

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0
C)
Ambient Temp
(
0

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C)
Manometer
Reading
(V)

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(A)

T1 T2 T3 T4 T5 T6 T7 T8
h1
cm

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h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

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Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor

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9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C

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12. Temperature indicator = 0 ? 300
0
C
(With compensation of ambient temperature up-to 50
0

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C)
13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1

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T8
Brass Pin Fin
Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.

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3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.

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Procedure:
Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.

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3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)

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1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2

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) /4}?2gha m
3
/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m

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?w Density of water = 1000 kg/m
3

?a = Density of air = 1.165 kg/m
3

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g = acceleration due to gravity = 9.81 m/s
2

Cd = Coefficient of discharge = 0.64
D = diameter of the orifice

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3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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A = area of the duct
4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin

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v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2
o
C
5. Heat transfer coefficient, h = Nu k / D

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Where Nu = Nusselt Number
6. Nusselt Number:
Nu = CRe
m
(Pr)

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0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk

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m= ?(hp/kA)
A = area of fin = (? x D
2
) /4
L = Length of the fin

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Tw ? average temperature
T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were

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Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced

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convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.

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40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?

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5. Define ? Heat Transfer
6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?

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10. What is meant by steady state heat conduction?
11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number

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15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.8

DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

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Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer
(ii) Electric Heater

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(iii) Stop watch
(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.

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The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on

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the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm

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2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm

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7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C
= (or) 0.1 Kcal / kg

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0
C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

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11. Temperature indicator digital 0.1
0
C L.C 0 - 200

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0
C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water

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Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th

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4
? Td
4
)
Where, A = area of the disc

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Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

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43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulations:
Proc

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edur
e:
1. H
eat the
water

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in the
tank by
the immersion heater up to a temperature of about 90
0
C.

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2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.

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5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

Result:

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The Stefan Boltzman constant was found out to be = _______________________ m/m
2
k
4
.

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Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,

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Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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Sl. No.
Hemisphere Temperature(
0
C) Avg. Temp.
of the

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Hemisphere
(Th)
T4
Steady
Temp. of

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Disc
T0 (Td)
Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number

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5. State Wien?s displacement law.
6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation

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10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?

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15. Explain the concept of black body.

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Viva ? voce

45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.9

DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

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Aim:
To measure emissivity of the test plate surface at various temperature
Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer
Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats

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and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.
Specifications:

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1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each

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5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.

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10. Temperature Indicator = 0 ? 300
0
C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:

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1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.

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6. See that the black plate is having a layer of lamp black uniformly.
Tabulation:
Sl.
No
Voltage

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Current

Black body
temp(

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0
C)
Avg.
temp.

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Polished body
temp (
0
C)
Avg.

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temp.

Enclosure
Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,

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W1 ? W2 = (Eb ? E) ? (Ts
4
? Ta
4
) A

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Eb ? E = (W1 ? W2) / ? (Ts
4
? Ta
4
) A

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E = Eb ? {(W1 ? W2) / ? (Ts
4
? Ta
4
) A}

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Where,
W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd
2

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m
2

T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure

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Ts = surface temperature of the discs (or T1)
Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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? = Stefan boltzman constant = 5.67 x 10
-8
W/m
2

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K
4


Schematic view of the test set-up:

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Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,

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2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by
the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

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Results:
The emissivity of the test plate surface is found to be _____________.
Outcome:
From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Emissivity
2. State Kirchoff?s law of radiation.

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3. What is meant by reflectivity?
4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?
6. What is meant by shape factor?
7. Define ? Radiation

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8. What is meant by monochromatic emissive power?
9. Define ? Emissive Power
10. What is meant by absorptivity?
11. Define ? Black Body
12. What is meant by transmissivity?

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13. State Plank's distribution law
14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

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49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.10

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EFFECTIVENESS OF PARALLEL / COUNTER
FLOW HEAT EXCHANGE

Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow

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Apparatus required:
(i) Experimental Setup
(ii) Stop watch
(iii) Thermometer
Theory:

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Heat exchangers are classified in three categories:
1. Transfer type
2. Storage type
3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is

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transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.
The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.

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The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water
which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.

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Specifications:
1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm

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5. Thermometers (for cold water) = 0 ? 50
0
C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100
0

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C - 2 Nos.
7. Measuring flask = 0 ? 1000 CC

50 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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8. Geyser: single phase type to obtain hot water supply
9. Thermo Cole insulation for outer pipe.
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.

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Tabulations:
Sl.
No.
Flow Hot Fluid (
0

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C) Cold Fluid (
0
C)
Time for
collection of

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hot fluid
Kg/sec
Time for
collection
of cold fluid

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Kg/sec
1 Parallel flow
Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)
1. Area of the pipe A = ? (D ? d) L
Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube
L = Length of the tube

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2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

51 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Where, m = mass flow rate Kg/ sec.
m = ?v/t, ? = density of water and t = time taken for hot water
Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet
Tho = Temperature of hot water outlet

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3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W
Where, m = mass flow rate
Cp = Specific heat of capacity
Tco = Temperature of cold water inlet

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Tci = Temperature of cold water outlet
4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W
Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)
?Tm = (?Ti - ?To) / In (?Ti/?To)

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Where, ?To = Tho ? Tco
?Ti = Thi ? Tci
6. Over all heat transfer coefficient
h = Q?/?Tm A W/m
2

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K
where Q? = (Qa + Qc) / 2

Procedure:
1. Place the thermometers in position and note down their readings when they are at room temperature and

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no water is flowing at either side. This is required to correct the temperature.
2. Start the flow on hot water side.
3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.
5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.

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6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.
7. Keeping the flow rates same, wait till the steady state conditions are reached.
8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.
10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

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52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Result:

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1. The values of effectiveness of heat exchanger were found as
(i) Parallel flow = ________.
(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)
(i) Parallel flow = ________.

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(ii) Counter flow = _________.

Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow
heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat

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exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Heat Exchanger
2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?
4. Write about the merits of drop wise condensation.

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5. What is meant by film wise and drop wise condensation?
6. What is meant by effectiveness?
7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?
9. Distinguish between regenerator and recuperates.

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10. What is meant by parallel flow heat exchanger?
11. What is meant by counter flow heat exchanger?
12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?
Viva ? voce

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53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.11

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DETERMINATION OF COP OF A REFRIGERATION
SYSTEM

Aim:
To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration

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system
Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch

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(iv) Experimental setup
Description:
1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a
reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.
2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated

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wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a
low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the
temperature of chilled water. The above unit is located on the trolley behind front panel.
3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic
expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum

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strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure
gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high
pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy
meter to measure the power consumed either by hater or by compressor.

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54 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
A. A compressor condenser unit placed inside trolley and fitted with
1. R-134a reciprocating compressor

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2. Condenser
3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan
4. A receiver with angle check valve
B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity
placed inside a well insulated wooden box and provided with

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5. Evaporator coil
6. Stirrer
7. Electric heater 230 V, A.C.
8. The sensing bulb of low temperature thermostat.
9. A high temperature thermostat.

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10. A Thermometer to measure the chilled water temperature
C. The front panel on which are mounted the following
11. Capillary expansion tube with isolating valve.
12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator
and isolating valve

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13. Drier cum strainer and sight glass
14. Thermostat at inlet and outlet of both evaporator and condenser
15. Pressure gauge at inlet and outlet of evaporator and condenser
16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out
17. Heat power regulator switch and regulator

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18. Energy meter to measure the power consumed either by hater or by compressor.



55 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.
2. The heater regulator should be switched off whenever not in use. Heating water beyond 40
0

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C may lead to
permanent damage of the entire system. A high temperature cut off thermostat is provided in the water
chiller, to cut off the heater beyond 30
0
C.Check the setting of the same before operation.

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3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.
4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.
5. The solenoid thermostat is adjusted to cut at 15
0
C and cut in at 10

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0
C of the chilled water. Do not alter the
same.
6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.
7. The space near the condenser should permit good ventilation to aid proper fan performance.

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8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked
in
0
F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,
calibrated in SI units, are not available.)

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9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to
obtain the pressure in MN/m
2
.e.g. P = x psig
= (x + 14.7) psia

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= (x + 14.7) / 145 MN/m
2
(MPa)
10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.
Formulae used:

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Let, State 1 indicates the entry of compressor.
State 2 indicates the exit of compressor.
State 3 indicates the exit from condenser.
State 4 indicates the entry to evaporator
P = Pressure (bar)

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T = Temperature (
0
C)
H = Specific enthalpy (kJ/kg)
v = Specific Volume (m

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3
/Kg)
n = Number of revolutions of energy meter disc.
t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)
t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)

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K = Energy meter constant = 3200 lmp / kWh
N = Speed of compressor = 2840 rpm
h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

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h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2
h3 = Specific enthalpy at Pc and T3 (kJ/kg)
h4 = h3
Stroke volume of compressor = (?/ 4) d

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2
l = 12.58 x 10
-6
m
3

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1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar
2. Average condenser pressure, Pc = (P2 + P3) / 2 bar
3. Heater input, Qe = (n / t1) x (3600 / k) kW
4. Compressor input, W = (n / t2) x (3600 / k) kW

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5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1
6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)
7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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57 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

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Sl.
No.

Initial
Temp.

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of water

Final
Temp.
of water

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Duration
of exp.

Delivery
pressure

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Delivery
Temp.

Condense

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Outlet
Pressure

Condense
Outlet

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Temp.


Pressure
after

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throttling

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Temp.
After
Throttli
ng

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Suction
pressur
e

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Suction
Temp.

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Time for
10 rev. of
compress
or energy

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meter



Height

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of water
in the
vessel

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58 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
Load Test with Capillary tube as expansion device:
1. Fill the chilled water calorimeter with pure water so that the evaporative coils are
fully immersed.
2. Select the capillary tube line by opening the shut-off valve on this line and closing

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the one on the thermostatic expansion valve line. The solenoid switch is switched OFF.
3. Start the compressor and run for some time so that the chilled water temperature
is lowered to the given test temperature.
4. Switch on the heater and slowly increase the power.
5. Allow The temperature in water calorimeter to reach the equilibrium

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temperature.
6. Connect energy meter to motor and heater by the selector switch one after another
and note down the time taken for 10 pulses of the energy meter disc.
7. Note down the pressure and temperature readings at locations 1,2,3 & 4 as
mentioned.

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8. Switch OFF the heater and the mains.
Result:
The load test on a refrigeration test rig was conducted and the results are as follows.
1. Actual C.O.P. of the system =____________.
2. Rhetorical C.O.P. of the system = ___________.

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3. Volumetric Efficiency = ___________.

Outcome:
From this experiment, conducting the load test on a refrigeration test rig and finding out the
volumetric efficiency and co-efficient of performance for any type of refrigerant is learnt and this experiment

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could be used in the areas such as Refrigerator and Air Conditioning.
Applications:
Refrigerator, Air Conditioning.

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59 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? COP
2. Which thermodynamic cycle is used in air conditioning of airplanes using air as refrigerant?
3. Define ? Ton of Refrigeration
4. What is meant by refrigeration?

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5. What is meant by air conditioning?
6. What are the four important properties of a good refrigerant?
7. How does the actual vapour compression cycle differ from that of the ideal cycle?
8. Name any four commonly used refrigerants.
9. What are the expansion devices used in a vapour compression plant?

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10. Why throttle valve is used in place of expansion cylinder for vapour compression refrigerant machine?
11. What are the merits of air refrigeration system?
12. What are the demerits of air refrigeration system?
13. Define ? Refrigerant
14. What is net refrigerating effect of the refrigerant?

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15. What are the methods to obtain sub cooling of refrigerant?

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Viva ? voce

60 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.12 EXPERIMENTS ON PSYCHROMETRIC PROCESS

Aim:
To conduct an experiment on psychrometric processes with air conditioning system

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Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Digital anemometer

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(v) Experimental setup
Description:
The test rig consist of
1. An air duct support of stand
2. A blower to set up air flow through the duct along with a speed control to vary the

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velocity of air.
3. A heater to rise the air temperature with regulator and energy meter.
4. Water spray, collecting tray, reservoir with gauge pump.
5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.
(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after cooling coil).

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6. The test rig consist of compressor, condenser unit placed inside trolley and fitted
with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for
condenser and (iv) Liquid receiver.
7. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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61 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I

Precautions:

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1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence
avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kw only for the motor
circuit.
2. Natural air currents in the room if in the direction of air duct may defect the experimental results and
hence the duct should be placed such that no wind from doors, windows, fan and cooling air from

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other test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan
and should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase
beyond 240 psi.
3. Never exceed dry bulb temperatures of 40
0

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C after the heater (station 2) otherwise the air duct may be
damaged.
4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may
exceed its maximum of 32
0

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C and calibration may be affected.
5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not
running this will lead to rise in temperature at the heater and may damage the heater and the air duct.
6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their
duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.

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7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer
is placed inside the reservoir at the top. This may have to the cleaned when necessary.
8. Do not open the gate valve fully otherwise water may be splashed outside and the waster
measurement may be in error.
S.

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N
o
Inlet temp
Outlet
temp

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Pressu
re
P1
Tem
p.

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T1
Pressu
re
P2
Temp.

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T2
Pressu
re
P3

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Tem
p.
T3

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Pressu
re
P4

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Temp.
T4
Energy
for 10
revolutio

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ns
Twet Tdry Twet Tdry Lb/in
o
C Lb/in
o

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C Lb/in
o
C Lb/in
o
C

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62 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

9. If the low pressure cut out comes in to action, it means that the Freon charge is insufficient and may

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have to be filled up. The suction pressure should never go below 2 psi as otherwise the compressor
seals will be damaged and air and moisture may enter the system.
10. The refrigerant strainer placed on the front panel should always be warm. If it cools and moisture
condenser on it, then the strainer might have to be charged by an experienced refrigeration
mechanics.

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11. The refrigerating system can work continuously for 2 hours, however if the room temperature is above
25
0
C the condenser may be heated up and the delivery pressure may rise. Do not exceed 240 psi.
Pour one or two glasses of drinking water over the fins of the condenser in order to reduce the

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delivery pressure.
12. After some months of operation the compressor may have to be topped up with oil and some quantity
of Freon-22 may have to be charged by an experienced mechanics.
13. See that distilled water is filled up in the plastic dishes provided under the wet bulb thermometers and
that the wicks are in tact otherwise erroneous readings may be obtained. These thermometers will

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show correct readings only when the fan is in operation.
14. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

Formulae used:

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1. Corresponding to the dry and wet bulb temperature at all the stations obtain the specific enthalpy and
specific humidity values from psychrometric chart.
i.e., h1 and w1 at tb1 and tw1 and so on.
2. Air flow rate, ma = (A x V) / v4 Kg / sec
Where, A = Area of duct at outlet in m

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2
(0.46 m x 0.086 m)
V = Air velocity ( m / sec)
V4 = Specific volume of moist air at station 4 using psychometric chart m
3

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/Kg
3. Moisture added from psychrometric chart, mw1 = ma (w3-w2) Kg / sec.
Where, w3 = Specific humidity at station 3
w2 = Specific humidity at station 2
4. Cooling effect produced on air, Qe = ma (h3 ? h4) kW.

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Where, h3 = Specific enthalpy at state 3 kJ/kg
h4 = Specific enthalpy at state 4 kJ/kg
5. Moisture condensed, mcl = ma (w3 ? w4) kg/sec
Where, w3 = Specific humidity at station 3
w4 = Specific humidity at station 4

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63 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Fill water in the wet bulb temperature probe trays.

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2. Start the main.
3. Start the blower and run it the required speed by keeping the speed regulator at
position.
4. Start the spray pump and open the gate valve suitably.
5. Start the heater.

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6. Select the expansion device (Capillary tube / Thermostatic expansion valve)
7. Start the cooling compressor.
8. Wait for some time till thermometers shown practically constant readings and note down the
following readings:
(i) Dry bulb temperatures tdb1, tdb2, tdb3, tdb4.

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(ii) Wet bulb temperatures twb1, twb2, twb3, twb4.
(iii) Spray water temperature, ts
(iv) Surface temperature of cooler, tm ( at control panel)
(v) Pressure gauge reading, pd ( at control panel)
(vi) Compound gauge reading, Ps ( at control panel)

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(vii) Level reduction?l? in spray reservoir (mm) during 5 min.
(viii) Amount of condensate collected ?lc?, in a measuring jar at cooler tray during a
run of 5 minutes at constant conditions.
(ix) Time in second ?SH? for 10 pulses of the energy meter disc connected to the
heater.

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(x) Time in seconds Sc for 10 pulses of the energy meter disc connected to cooler
compressor.
Result:
Experiment on psychrometric processes with air conditioning system was drawn
Outcome:

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From this experiment, conducting the test on psychrometric processes with air
conditioning system is learnt and this experiment could be used in all types of air conditioning systems.

Applications:
Air Conditioning.

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64 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the commonly used unit of refrigeration?
2. Distinguish between summer air conditioning and winter air conditioning.
3. Define ? RSHF Line

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4. Define ? By Pass Factor of a Heating Coil
5. What is the effect of sub cooling a refrigerant in a vapour compression cycle?
6. What is the function of analyzer and rectifier in an absorption system?
7. What is the purpose of generator assembly in vapour absorption refrigeration system?
8. State the substance used in the Lithium Bromide system and their functions.

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9. Differentiate wet compression from dry compression.
10. Define ? Apparatus Dew Point
11. What is meant by dew point temperature?
12. Define ? Wet Bulb Temperature
13. Define ? Degree of Saturation

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14. What is meant by specific humidity?
15. Define ? Relative Humidity

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Viva ? voce

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65 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.13

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PERFORMANCE TEST ON A RECIPROCATING
AIR COMPRESSOR

Aim:
To conduct a load test on the 2 - stage reciprocating air compressor to determine the isothermal and

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volumetric Efficiencies at various delivery pressures

Apparatus required:
* Air compressor with accessories.
* Stop watch.

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Description:
Two stage air compressors is a reciprocating type driven by a prime mover. The test rig consist of a base on
which the tank is mounted. The outlet of the compressor is connected to the receiver. The suction is
connected to air tank with a calibrated orifice plate through a water manometer. The input to the motor is
recorded by an energy meter. The temperature and pressure of the air compressed is indicated by a

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thermometer and pressure gauge.
Specifications:
1. Air compressor:
* LP Bore, DLP = 63.0 mm.
* HP Bore, DHP = 79.0 mm.

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* Stroke, L = 80.0 mm.
* Speed, N = 1440 rpm (5 HP)
* Effective radius = 0.193 m
2. Air receiver capacity = 0.33 m3
3. Orifice, diameter, d0 = 12 mm

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4. Orifice area,. A0 : ?d0
2
/ 4 = ----------- m
2

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5. Coefficient of discharge C d. = 0.6
6. Energy-meter constant = 200 rev / kWh

66 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I

Observation Table: II
Sl.
No.

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Actual
Discharge
Va
Theoritical
Discharge

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Vt
Volumetric
Efficiency
?
Power

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Input

Output
Power

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Overall
Efficiency
?0
Isothermal
Workdone

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IwD
Polytropic
Workdone
PwD
Isothermal

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Efficiency
?iso
m
3
/sec m

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3
/sec % kW kW % J/Kg J/Kg %


Sl.

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No.
Pressure
p
Manometer
h1

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Manometer
h2
Time for 5 revolutions Energy meter Speed of the compressor Temperature
T1
Temperature

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T1
Kg/cm
2
Cm cm sec rpm
o

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C
o
C

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67 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Check whether manometer is filled with water up to the required level.

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2. The maximum pressure in the receiver tank should not exceed 12 kg / cm
2

Procedure:
1. Ensure that gauge pressure in the tank is zero.

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2. Start the compressor. Read the receiver pressure gauge for a particular pressure.
3. Maintain the pressure constant by adjusting the outlet valve.
4. Note down the manometer reading and time taken for 3 revolution of the energy
Formulae used:
1. Density of air at RTP:

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? RTP = ? NTP X 273 Kg/ m
3

(273 + Room Temp)
Where density of air at NTP = 1.293 Kg/ m

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3
.

2. Air head causing flow:
ha RTP = (h1 - h2) x ? water m

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?a RTP
Where,
(h1- h2) = Difference in manometer liquid, in m.

3. Actual volume at RTP:

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Va RTP = C.d x Ao x ? 2 g ha RTP
Where,
C d= Coefficient of discharge = 0.6.
A o = Area of orifice = ?(d0)
2

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m
2
.
4
Diameter of orifice d o = 0.01 m.

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4. Actual volume at NTP:
Va NTP = VaRTP x T NTP
T RTP
Where,
T NTP = Normal temp - 273

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o
k
T RTP = Room temp -
o
c (273 + TROOM )

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68 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

5. Theoretical Volume of air: (at intake conditions)
V T = ?D

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2
x L x Nc m
3
/ sec.
4 x 60

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D = LP Bore diameter = 88.5 mm.
L = Stroke length = 88.9 mm.
Nc = Compressor speed rpm.
6. Volumetric Efficiency:(for LP stage)
?vol = Va NTP x 100%

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Vt
7. Shaft Input through Energy meter:

= 1 x n x ?t x ?m x 3600 kw.
( Ec x t )

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Where,
Ec = Energy meter constant = 200 rev / kWh
?t = Efficiency for transmission = 0.95.
? m = Efficiency for motor = 0.90.
t = Time for 'n' revolution of energy meter disc.

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n = no. of rev. of Energy meter disc.

8. Isothermal power:
= Pa x Va RTP x log e (R) W
1000

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Pa = Atmospheric pressure in N/ m
2
= 1.01325 x 10
5
N / m

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2
.
R = (Pressure gauge reading + atmospheric pressure)
atmospheric pressure.
9. Isothermal efficiency:

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? ISO = Isothermal power x 100%
Shaft input

Result:
The values of isothermal and volumetric efficiency at various delivery pressures have been studied &

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graph between Pressure Vs Volumetric efficiency and Pressure Vs Isothermal efficiency are drawn.

FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

--- Content provided by FirstRanker.com ---

--- Content provided by FirstRanker.com ---

VISION
MISSION
VISION

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MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex

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software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills

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4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning

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To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the

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career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society

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7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with

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coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:

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HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube

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5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface

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10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes

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13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.

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4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system

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13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES

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7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6

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2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3

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Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5

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Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7

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Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS

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11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68

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15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT

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USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate

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assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The

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heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:

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1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2

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Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

9 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently

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5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm

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2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm

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7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100
0

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C
9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm

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11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A

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16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C

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19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulation:
Sl. No. Voltmeter
V
Ammeter

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A
Main heater (
0
C) Test Plate (
0

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C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.

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Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.

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4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.

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4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?

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9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?

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14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?

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19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF

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PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus

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Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter

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(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm

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5. The effective length of the above = 500 mm

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Precautions:

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1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W

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Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material

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k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.

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No.
Voltage
(V)
Current
(A)

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Heater Temperature
(
0
C)
Asbestos Temperature

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(
0
C)
Saw dust
Temperature (

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0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.

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2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.

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6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.

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The thermal conductivity of resistive material = _________________ W /m
2
-K

Outcome:

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From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:

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Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. Define ? Nusselt Number(Nu)

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2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)

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7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?

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12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?

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17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION

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FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The

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temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold

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fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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Schematic view of the test set-up:
mm

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mm

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Specifications:

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1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.

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5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A

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7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

Tabulation:

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Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m

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2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (

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0
C) ?
2. hL / k = A { g L
3
?T Cp ?/2v

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2
}
n

Where, hL / k are called Nusselt Number.

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L
3
g?T / v
2
is called Grashof number.

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?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid

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? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta

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For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)

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0.25
for 10
4
< Gr.Pr.<10
8

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hL / k = 0.13 (Gr.Pr)
1/3
for 10
8

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< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.

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4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as

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Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m
2

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K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC

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engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?

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6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?

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11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.

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16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to

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the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

Sl. No. Voltage Current Temperature in (
0

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C)
Manometer
reading of water
in h in meter

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(V) (A)
T1

T2

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T3

T4

T5

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T6

h1
cm

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h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer

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6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0
C
(Calibrated for chromel alumel thermocouple)

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8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.

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7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat

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input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)

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Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o
C)

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= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di

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2
?2gH x (?w / ?a) m
3
/hr
3. ha = qa /A(Ts- Ta) W / m

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2
K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

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Ta = Average temperature of air = (T1 + T6)/2
o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4

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o
C
Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m

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3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

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d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

using this procedure obtain the value of ?ha? for different air flow rate

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4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2
)/4]

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v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o
C
5. Nusselt Number:

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Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

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27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m

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2

k = Thermal conductivity of fluid W/m
2
K

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Nu = 0.023 (Re)
0.8
(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

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Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m

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2
K
htheoritical = -------------- W/m
2
K

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Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?

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4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?

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9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.

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14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

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29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

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Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the

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thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The

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temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is

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the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm

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3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat

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input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

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30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.

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7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow

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R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:

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Sl.No. Voltmeter
reading
(V)
Ammeter
reading

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(A)
T1
(
0
C)

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T2
(
0
C)
T3

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(
0
C)
T4
(

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0
C)
T5
(
0

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C)
T6
(
0
C)

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T7
(
0
C)
T8

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(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Composite wall apparatus set-up

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Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

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Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal

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conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?

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10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

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33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY

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OF INSULATING POWDER

Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

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The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit

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is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

Procedure:

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1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter

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reading( V)
Ammeter
reading (A)
T1
(

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0
C)
T2
(
0

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C)
T3
(
0
C)

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T4
(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1

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Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.


34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Fig. 1 Apparatus of thermal conductivity of insulating powder

[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater

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control]

Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

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Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to

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be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?

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4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?

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9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)

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14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?

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19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

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36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

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HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:

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A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is

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shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:
Sl.
No.

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V I

Fin Temperatures (
0
C)

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Ambient Temp
(
0
C)
Manometer

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Reading
(V)

(A)

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T1 T2 T3 T4 T5 T6 T7 T8
h1
cm
h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm

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3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.

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11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C
12. Temperature indicator = 0 ? 300
0

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C
(With compensation of ambient temperature up-to 50
0
C)
13. Dimmer stat for heat input controls 230 V, 2 A

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14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8
Brass Pin Fin

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Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

16. Ammeter = 0 ? 2 A

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.

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5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:
Forced Convection:

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1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient

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temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)

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Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m
3

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/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m
3

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?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s
2

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Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

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39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

A = area of the duct
4. Reynold?s Number:

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Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2

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o
C
5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number
6. Nusselt Number:

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Nu = CRe
m
(Pr)
0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)

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h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk
m= ?(hp/kA)
A = area of fin = (? x D

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2
) /4
L = Length of the fin
Tw ? average temperature
T? ? ambient (surface) temperature (T6)

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8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

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Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through

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pin-fin is to be found.


40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Extended Surface

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2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer
6. Define ? Fin Efficiency

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7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?
11. Define ? Convection

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12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

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41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.8

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DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus

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Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Geyser water

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Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to

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measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response

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of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm

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4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg

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0
C
= (or) 0.1 Kcal / kg
0
C

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9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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11. Temperature indicator digital 0.1
0
C L.C 0 - 200
0
C with built-in cold junction compensation and a timer set

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for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically

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there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4
? Td

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4
)
Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0

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dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:
Proc
edur
e:

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1. H
eat the
water
in the
tank by

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the immersion heater up to a temperature of about 90
0
C.
2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.

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4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate

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thermocouple).

Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m
2

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k
4
.

Outcome:

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From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.

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.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

Sl. No.
Hemisphere Temperature(

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0
C) Avg. Temp.
of the
Hemisphere
(Th)

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T4
Steady
Temp. of
Disc
T0 (Td)

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Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]

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2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number
5. State Wien?s displacement law.
6. What is the significance of Biot Number?

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7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation
10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]

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12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

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45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.9

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DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

Aim:
To measure emissivity of the test plate surface at various temperature

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:

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The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp

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black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.
Specifications:
1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W

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3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A

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7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300
0

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C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Use proper voltage range on Voltmeter.

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3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.
Tabulation:

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Sl.
No
Voltage

Current

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Black body
temp(
0
C)

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Avg.
temp.

Polished body
temp (

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0
C)
Avg.
temp.

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Enclosure
Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts
4

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? Ta
4
) A
Eb ? E = (W1 ? W2) / ? (Ts
4

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? Ta
4
) A
E = Eb ? {(W1 ? W2) / ? (Ts
4

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? Ta
4
) A}
Where,
W1 = Heater input to black plate = V1 x I1 W

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W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd
2
m
2

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T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)
Eb = Emissivity of black plate = 1

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E = Emissivity of Test plate

47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

? = Stefan boltzman constant = 5.67 x 10

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-8
W/m
2
K
4

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Schematic view of the test set-up:

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Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by
the dimmer stat so that the two plates will be maintained at the same temperature.

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3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

Results:
The emissivity of the test plate surface is found to be _____________.

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Outcome:
From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

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48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Emissivity
2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?
4. State Lambert?s cosine law.

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5. What is the purpose of radiation shield?
6. What is meant by shape factor?
7. Define ? Radiation
8. What is meant by monochromatic emissive power?
9. Define ? Emissive Power

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10. What is meant by absorptivity?
11. Define ? Black Body
12. What is meant by transmissivity?
13. State Plank's distribution law
14. What is meant by gray body?

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15. Define ? Irradiation

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Viva ? voce

49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.10

EFFECTIVENESS OF PARALLEL / COUNTER
FLOW HEAT EXCHANGE

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Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:
(i) Experimental Setup

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(ii) Stop watch
(iii) Thermometer
Theory:
Heat exchangers are classified in three categories:
1. Transfer type

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2. Storage type
3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.
The transfer type exchangers are further classified accordant to flow arrangements as:

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i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water
which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water

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flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:
1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm

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2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50
0

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C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100
0
C - 2 Nos.
7. Measuring flask = 0 ? 1000 CC

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8. Geyser: single phase type to obtain hot water supply
9. Thermo Cole insulation for outer pipe.

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Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Tabulations:
Sl.

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No.
Flow Hot Fluid (
0
C) Cold Fluid (
0

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C)
Time for
collection of
hot fluid
Kg/sec

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Time for
collection
of cold fluid
Kg/sec
1 Parallel flow

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Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)
1. Area of the pipe A = ? (D ? d) L

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Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube
L = Length of the tube

2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

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51 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Where, m = mass flow rate Kg/ sec.
m = ?v/t, ? = density of water and t = time taken for hot water

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Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet
Tho = Temperature of hot water outlet

3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W

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Where, m = mass flow rate
Cp = Specific heat of capacity
Tco = Temperature of cold water inlet
Tci = Temperature of cold water outlet
4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W

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Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)
?Tm = (?Ti - ?To) / In (?Ti/?To)
Where, ?To = Tho ? Tco
?Ti = Thi ? Tci

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6. Over all heat transfer coefficient
h = Q?/?Tm A W/m
2
K
where Q? = (Qa + Qc) / 2

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Procedure:
1. Place the thermometers in position and note down their readings when they are at room temperature and
no water is flowing at either side. This is required to correct the temperature.
2. Start the flow on hot water side.

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3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.
5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.
6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.
7. Keeping the flow rates same, wait till the steady state conditions are reached.

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8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.
10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Result:
1. The values of effectiveness of heat exchanger were found as
(i) Parallel flow = ________.

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(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)
(i) Parallel flow = ________.
(ii) Counter flow = _________.

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Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow
heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat
exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.
Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.



1. Define ? Heat Exchanger

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2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?
4. Write about the merits of drop wise condensation.
5. What is meant by film wise and drop wise condensation?
6. What is meant by effectiveness?

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7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?
9. Distinguish between regenerator and recuperates.
10. What is meant by parallel flow heat exchanger?
11. What is meant by counter flow heat exchanger?

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12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?
Viva ? voce

53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.11

DETERMINATION OF COP OF A REFRIGERATION
SYSTEM

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Aim:
To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration
system
Apparatus required:

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(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Experimental setup
Description:

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1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a
reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.
2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated
wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a
low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the

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temperature of chilled water. The above unit is located on the trolley behind front panel.
3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic
expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum
strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure
gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high

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pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy
meter to measure the power consumed either by hater or by compressor.

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54 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
A. A compressor condenser unit placed inside trolley and fitted with
1. R-134a reciprocating compressor
2. Condenser
3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan

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4. A receiver with angle check valve
B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity
placed inside a well insulated wooden box and provided with
5. Evaporator coil
6. Stirrer

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7. Electric heater 230 V, A.C.
8. The sensing bulb of low temperature thermostat.
9. A high temperature thermostat.
10. A Thermometer to measure the chilled water temperature
C. The front panel on which are mounted the following

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11. Capillary expansion tube with isolating valve.
12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator
and isolating valve
13. Drier cum strainer and sight glass
14. Thermostat at inlet and outlet of both evaporator and condenser

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15. Pressure gauge at inlet and outlet of evaporator and condenser
16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out
17. Heat power regulator switch and regulator
18. Energy meter to measure the power consumed either by hater or by compressor.

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55 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:

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1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.
2. The heater regulator should be switched off whenever not in use. Heating water beyond 40
0
C may lead to
permanent damage of the entire system. A high temperature cut off thermostat is provided in the water

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chiller, to cut off the heater beyond 30
0
C.Check the setting of the same before operation.
3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.
4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.

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5. The solenoid thermostat is adjusted to cut at 15
0
C and cut in at 10
0
C of the chilled water. Do not alter the

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same.
6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.
7. The space near the condenser should permit good ventilation to aid proper fan performance.
8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked
in

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0
F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,
calibrated in SI units, are not available.)
9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to
obtain the pressure in MN/m

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2
.e.g. P = x psig
= (x + 14.7) psia
= (x + 14.7) / 145 MN/m
2

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(MPa)
10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.
Formulae used:
Let, State 1 indicates the entry of compressor.
State 2 indicates the exit of compressor.

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State 3 indicates the exit from condenser.
State 4 indicates the entry to evaporator
P = Pressure (bar)
T = Temperature (
0

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C)
H = Specific enthalpy (kJ/kg)
v = Specific Volume (m
3
/Kg)

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n = Number of revolutions of energy meter disc.
t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)
t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)
K = Energy meter constant = 3200 lmp / kWh
N = Speed of compressor = 2840 rpm

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h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

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h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2

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h3 = Specific enthalpy at Pc and T3 (kJ/kg)
h4 = h3
Stroke volume of compressor = (?/ 4) d
2
l = 12.58 x 10

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-6
m
3

1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar

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2. Average condenser pressure, Pc = (P2 + P3) / 2 bar
3. Heater input, Qe = (n / t1) x (3600 / k) kW
4. Compressor input, W = (n / t2) x (3600 / k) kW
5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1
6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)

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7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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57 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I


Sl.
No.

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Initial
Temp.
of water

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Final
Temp.
of water
Duration
of exp.

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Delivery
pressure

Delivery

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Temp.

Condense
Outlet
Pressure

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Condense
Outlet
Temp.

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Pressure
after
throttling

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Temp.

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After
Throttli
ng

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Suction
pressur
e
Suction
Temp.

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Time for

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10 rev. of
compress
or energy
meter

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Height
of water
in the

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vessel

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58 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
Load Test with Capillary tube as expansion device:

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1. Fill the chilled water calorimeter with pure water so that the evaporative coils are
fully immersed.
2. Select the capillary tube line by opening the shut-off valve on this line and closing
the one on the thermostatic expansion valve line. The solenoid switch is switched OFF.
3. Start the compressor and run for some time so that the chilled water temperature

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is lowered to the given test temperature.
4. Switch on the heater and slowly increase the power.
5. Allow The temperature in water calorimeter to reach the equilibrium
temperature.
6. Connect energy meter to motor and heater by the selector switch one after another

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and note down the time taken for 10 pulses of the energy meter disc.
7. Note down the pressure and temperature readings at locations 1,2,3 & 4 as
mentioned.
8. Switch OFF the heater and the mains.
Result:

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The load test on a refrigeration test rig was conducted and the results are as follows.
1. Actual C.O.P. of the system =____________.
2. Rhetorical C.O.P. of the system = ___________.
3. Volumetric Efficiency = ___________.

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Outcome:
From this experiment, conducting the load test on a refrigeration test rig and finding out the
volumetric efficiency and co-efficient of performance for any type of refrigerant is learnt and this experiment
could be used in the areas such as Refrigerator and Air Conditioning.
Applications:

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Refrigerator, Air Conditioning.

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59 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? COP

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2. Which thermodynamic cycle is used in air conditioning of airplanes using air as refrigerant?
3. Define ? Ton of Refrigeration
4. What is meant by refrigeration?
5. What is meant by air conditioning?
6. What are the four important properties of a good refrigerant?

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7. How does the actual vapour compression cycle differ from that of the ideal cycle?
8. Name any four commonly used refrigerants.
9. What are the expansion devices used in a vapour compression plant?
10. Why throttle valve is used in place of expansion cylinder for vapour compression refrigerant machine?
11. What are the merits of air refrigeration system?

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12. What are the demerits of air refrigeration system?
13. Define ? Refrigerant
14. What is net refrigerating effect of the refrigerant?
15. What are the methods to obtain sub cooling of refrigerant?

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Viva ? voce

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60 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.12 EXPERIMENTS ON PSYCHROMETRIC PROCESS

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Aim:
To conduct an experiment on psychrometric processes with air conditioning system
Apparatus required:
(i) Thermometer

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(ii) Electric Heater
(iii) Stop watch
(iv) Digital anemometer
(v) Experimental setup
Description:

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The test rig consist of
1. An air duct support of stand
2. A blower to set up air flow through the duct along with a speed control to vary the
velocity of air.
3. A heater to rise the air temperature with regulator and energy meter.

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4. Water spray, collecting tray, reservoir with gauge pump.
5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.
(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after cooling coil).
6. The test rig consist of compressor, condenser unit placed inside trolley and fitted
with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for

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condenser and (iv) Liquid receiver.
7. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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61 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I

Precautions:
1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence
avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kw only for the motor

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circuit.
2. Natural air currents in the room if in the direction of air duct may defect the experimental results and
hence the duct should be placed such that no wind from doors, windows, fan and cooling air from
other test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan
and should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase

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beyond 240 psi.
3. Never exceed dry bulb temperatures of 40
0
C after the heater (station 2) otherwise the air duct may be
damaged.

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4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may
exceed its maximum of 32
0
C and calibration may be affected.
5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not

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running this will lead to rise in temperature at the heater and may damage the heater and the air duct.
6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their
duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.
7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer
is placed inside the reservoir at the top. This may have to the cleaned when necessary.

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8. Do not open the gate valve fully otherwise water may be splashed outside and the waster
measurement may be in error.
S.
N
o

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Inlet temp
Outlet
temp
Pressu
re

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P1
Tem
p.
T1
Pressu

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re
P2
Temp.
T2
Pressu

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re
P3

Tem
p.

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T3


Pressu
re

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P4


Temp.
T4

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Energy
for 10
revolutio
ns
Twet Tdry Twet Tdry Lb/in

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o
C Lb/in
o
C Lb/in
o

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C Lb/in
o
C

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62 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

9. If the low pressure cut out comes in to action, it means that the Freon charge is insufficient and may
have to be filled up. The suction pressure should never go below 2 psi as otherwise the compressor
seals will be damaged and air and moisture may enter the system.

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10. The refrigerant strainer placed on the front panel should always be warm. If it cools and moisture
condenser on it, then the strainer might have to be charged by an experienced refrigeration
mechanics.
11. The refrigerating system can work continuously for 2 hours, however if the room temperature is above
25

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0
C the condenser may be heated up and the delivery pressure may rise. Do not exceed 240 psi.
Pour one or two glasses of drinking water over the fins of the condenser in order to reduce the
delivery pressure.
12. After some months of operation the compressor may have to be topped up with oil and some quantity

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of Freon-22 may have to be charged by an experienced mechanics.
13. See that distilled water is filled up in the plastic dishes provided under the wet bulb thermometers and
that the wicks are in tact otherwise erroneous readings may be obtained. These thermometers will
show correct readings only when the fan is in operation.
14. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and

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corrosion damage.

Formulae used:
1. Corresponding to the dry and wet bulb temperature at all the stations obtain the specific enthalpy and
specific humidity values from psychrometric chart.

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i.e., h1 and w1 at tb1 and tw1 and so on.
2. Air flow rate, ma = (A x V) / v4 Kg / sec
Where, A = Area of duct at outlet in m
2
(0.46 m x 0.086 m)

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V = Air velocity ( m / sec)
V4 = Specific volume of moist air at station 4 using psychometric chart m
3
/Kg
3. Moisture added from psychrometric chart, mw1 = ma (w3-w2) Kg / sec.

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Where, w3 = Specific humidity at station 3
w2 = Specific humidity at station 2
4. Cooling effect produced on air, Qe = ma (h3 ? h4) kW.
Where, h3 = Specific enthalpy at state 3 kJ/kg
h4 = Specific enthalpy at state 4 kJ/kg

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5. Moisture condensed, mcl = ma (w3 ? w4) kg/sec
Where, w3 = Specific humidity at station 3
w4 = Specific humidity at station 4

63 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Fill water in the wet bulb temperature probe trays.
2. Start the main.
3. Start the blower and run it the required speed by keeping the speed regulator at

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position.
4. Start the spray pump and open the gate valve suitably.
5. Start the heater.
6. Select the expansion device (Capillary tube / Thermostatic expansion valve)
7. Start the cooling compressor.

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8. Wait for some time till thermometers shown practically constant readings and note down the
following readings:
(i) Dry bulb temperatures tdb1, tdb2, tdb3, tdb4.
(ii) Wet bulb temperatures twb1, twb2, twb3, twb4.
(iii) Spray water temperature, ts

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(iv) Surface temperature of cooler, tm ( at control panel)
(v) Pressure gauge reading, pd ( at control panel)
(vi) Compound gauge reading, Ps ( at control panel)
(vii) Level reduction?l? in spray reservoir (mm) during 5 min.
(viii) Amount of condensate collected ?lc?, in a measuring jar at cooler tray during a

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run of 5 minutes at constant conditions.
(ix) Time in second ?SH? for 10 pulses of the energy meter disc connected to the
heater.
(x) Time in seconds Sc for 10 pulses of the energy meter disc connected to cooler
compressor.

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Result:
Experiment on psychrometric processes with air conditioning system was drawn
Outcome:
From this experiment, conducting the test on psychrometric processes with air
conditioning system is learnt and this experiment could be used in all types of air conditioning systems.

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Applications:
Air Conditioning.

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64 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the commonly used unit of refrigeration?
2. Distinguish between summer air conditioning and winter air conditioning.
3. Define ? RSHF Line
4. Define ? By Pass Factor of a Heating Coil
5. What is the effect of sub cooling a refrigerant in a vapour compression cycle?

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6. What is the function of analyzer and rectifier in an absorption system?
7. What is the purpose of generator assembly in vapour absorption refrigeration system?
8. State the substance used in the Lithium Bromide system and their functions.
9. Differentiate wet compression from dry compression.
10. Define ? Apparatus Dew Point

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11. What is meant by dew point temperature?
12. Define ? Wet Bulb Temperature
13. Define ? Degree of Saturation
14. What is meant by specific humidity?
15. Define ? Relative Humidity

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Viva ? voce

65 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.13

PERFORMANCE TEST ON A RECIPROCATING
AIR COMPRESSOR

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Aim:
To conduct a load test on the 2 - stage reciprocating air compressor to determine the isothermal and
volumetric Efficiencies at various delivery pressures

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Apparatus required:
* Air compressor with accessories.
* Stop watch.
Description:
Two stage air compressors is a reciprocating type driven by a prime mover. The test rig consist of a base on

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which the tank is mounted. The outlet of the compressor is connected to the receiver. The suction is
connected to air tank with a calibrated orifice plate through a water manometer. The input to the motor is
recorded by an energy meter. The temperature and pressure of the air compressed is indicated by a
thermometer and pressure gauge.
Specifications:

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1. Air compressor:
* LP Bore, DLP = 63.0 mm.
* HP Bore, DHP = 79.0 mm.
* Stroke, L = 80.0 mm.
* Speed, N = 1440 rpm (5 HP)

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* Effective radius = 0.193 m
2. Air receiver capacity = 0.33 m3
3. Orifice, diameter, d0 = 12 mm
4. Orifice area,. A0 : ?d0
2

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/ 4 = ----------- m
2

5. Coefficient of discharge C d. = 0.6
6. Energy-meter constant = 200 rev / kWh

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66 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

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Observation Table: II
Sl.
No.
Actual
Discharge

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Va
Theoritical
Discharge
Vt
Volumetric

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Efficiency
?
Power
Input

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Output
Power

Overall
Efficiency

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?0
Isothermal
Workdone
IwD
Polytropic

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Workdone
PwD
Isothermal
Efficiency
?iso

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m
3
/sec m
3
/sec % kW kW % J/Kg J/Kg %

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Sl.
No.
Pressure

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p
Manometer
h1
Manometer
h2

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Time for 5 revolutions Energy meter Speed of the compressor Temperature
T1
Temperature
T1
Kg/cm

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2
Cm cm sec rpm
o
C
o

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C



67 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Check whether manometer is filled with water up to the required level.
2. The maximum pressure in the receiver tank should not exceed 12 kg / cm
2

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Procedure:
1. Ensure that gauge pressure in the tank is zero.
2. Start the compressor. Read the receiver pressure gauge for a particular pressure.
3. Maintain the pressure constant by adjusting the outlet valve.

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4. Note down the manometer reading and time taken for 3 revolution of the energy
Formulae used:
1. Density of air at RTP:
? RTP = ? NTP X 273 Kg/ m
3

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(273 + Room Temp)
Where density of air at NTP = 1.293 Kg/ m
3
.

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2. Air head causing flow:
ha RTP = (h1 - h2) x ? water m
?a RTP
Where,

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(h1- h2) = Difference in manometer liquid, in m.

3. Actual volume at RTP:
Va RTP = C.d x Ao x ? 2 g ha RTP
Where,

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C d= Coefficient of discharge = 0.6.
A o = Area of orifice = ?(d0)
2
m
2

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.
4
Diameter of orifice d o = 0.01 m.
4. Actual volume at NTP:
Va NTP = VaRTP x T NTP

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T RTP
Where,
T NTP = Normal temp - 273
o
k

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T RTP = Room temp -
o
c (273 + TROOM )

68 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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5. Theoretical Volume of air: (at intake conditions)
V T = ?D
2
x L x Nc m

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3
/ sec.
4 x 60
D = LP Bore diameter = 88.5 mm.
L = Stroke length = 88.9 mm.

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Nc = Compressor speed rpm.
6. Volumetric Efficiency:(for LP stage)
?vol = Va NTP x 100%
Vt
7. Shaft Input through Energy meter:

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= 1 x n x ?t x ?m x 3600 kw.
( Ec x t )
Where,
Ec = Energy meter constant = 200 rev / kWh

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?t = Efficiency for transmission = 0.95.
? m = Efficiency for motor = 0.90.
t = Time for 'n' revolution of energy meter disc.
n = no. of rev. of Energy meter disc.

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8. Isothermal power:
= Pa x Va RTP x log e (R) W
1000
Pa = Atmospheric pressure in N/ m
2

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= 1.01325 x 10
5
N / m
2
.

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R = (Pressure gauge reading + atmospheric pressure)
atmospheric pressure.
9. Isothermal efficiency:
? ISO = Isothermal power x 100%
Shaft input

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Result:
The values of isothermal and volumetric efficiency at various delivery pressures have been studied &
graph between Pressure Vs Volumetric efficiency and Pressure Vs Isothermal efficiency are drawn.

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69 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Outcome:
From this experiment, conducting the load test on two stage reciprocating air compressor for

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determining the isothermal and volumetric Efficiencies at various delivery pressures is understood and this
experiment could be used in the areas such as Refrigerator, Air Conditioning, IC engines, etc.

Applications:
Refrigerator, Air Conditioning, IC engines.

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1. How are air compressors classified?
2. Define ? Isothermal Efficiency of Air Compressor
3. What is meant by FAD (Free Air Delivery)?

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4. What is meant by perfect inter-cooling?
5. Define ? Clearance Ratio of an Air Compressor
6. List out the applications of compressed air.
7. What are the types of air compressors?
8. What is meant by single acting compressor?

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9. What is meant by double acting compressor?
10. What is meant by single stage compressor?
11. What is meant by multi stage compressor?
12. Indicate the applications of reciprocating compressors in industry>
13. Define ? Mechanical Efficiency

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14. What is meant by compression ratio?
15. What are the factors that affect the volumetric efficiency of a reciprocating compressor?

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Viva ? voce
FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart

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and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION

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VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence

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To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design

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products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies

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5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering

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2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools

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6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms

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9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder

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4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant

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9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system

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12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection

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experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.

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12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC

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Boiler.



COURSE OBJECTIVES

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COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS

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1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11

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3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21

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5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31

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7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47

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CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14

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Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate

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method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters

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together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples

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No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2

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(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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9 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help

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of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:

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1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm

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6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100

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0
C
9. Maximum temperature of the hot plate = 170
0
C

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10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V

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15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0

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C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:
Sl. No. Voltmeter
V

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Ammeter
A
Main heater (
0
C) Test Plate (

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0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:

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1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single

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phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.

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8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.

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3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?

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8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?

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13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?

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18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:

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To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple

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(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.

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There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.

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4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.

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4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging

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k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:

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Sl.
No.
Voltage
(V)
Current

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(A)
Heater Temperature
(
0
C)

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Asbestos Temperature
(
0
C)
Saw dust

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Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos

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layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:

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The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)

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6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?

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11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.

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16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical

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tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which

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in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.

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The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Schematic view of the test set-up:

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mm
mm

19 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch

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Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples

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6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}

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Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W

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Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L
3

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?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v
2

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is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid

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v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity

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?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.

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hL / k = 0.56 (Gr.Pr)
0.25
for 10
4
< Gr.Pr.<10

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8

hL / k = 0.13 (Gr.Pr)
1/3
for 10

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8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).

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3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:

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The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m

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2
K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing

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heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?

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5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)

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10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness

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15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?

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20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:

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To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer

Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air

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stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of

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orifice meter and the water manometer fitted on the board.


24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

Sl. No. Voltage Current Temperature in (

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0
C)
Manometer
reading of water
in h in meter

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(V) (A)
T1

T2

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T3

T4

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T5

T6

h1

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cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor

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5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0
C

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(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:

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1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.

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6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.

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2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. The rate at which air is getting heated is calculated as

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qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o

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C)
= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate

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Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m
3
/hr

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3. ha = qa /A(Ts- Ta) W / m
2
K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m

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2

Ta = Average temperature of air = (T1 + T6)/2
o
C

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Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C
Cd = 0.64
H = Difference of water level in manometer m

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?w Density of water = 1000 Kg/m
3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

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d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

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using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2

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)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o
C

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5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

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27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k

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? = Viscosity Ns/m
2

k = Thermal conductivity of fluid W/m
2

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K
Nu = 0.023 (Re)
0.8
(Pr)
0.4

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Bulk mean temperature = (T1 + T6)/2

Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.

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hactual = -------------- W/m
2
K
htheoritical = -------------- W/m
2

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K

Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?

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3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?

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8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection

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13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

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Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,

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the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure

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temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat

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flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm

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2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.

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2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

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30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature

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gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:

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Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R

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Tabulation:
Sl.No. Voltmeter
reading
(V)
Ammeter

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reading
(A)
T1
(
0

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C)
T2
(
0
C)

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T3
(
0
C)
T4

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(
0
C)
T5
(

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0
C)
T6
(
0

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C)
T7
(
0
C)

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T8
(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Composite wall apparatus set-up

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Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W

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c. Asbestos section = ------------W

Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure

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Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?

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5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.

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9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

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33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

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DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

Aim:
To find out the thermal conductivity of insulating powder by conduction

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Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A

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multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

Procedure:

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1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.

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5. Repeat the experiments for different power inputs.


The readings are tabulated below

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Sl.No. Voltmeter
reading( V)
Ammeter
reading (A)
T1

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(
0
C)
T2
(

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0
C)
T3
(
0

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C)
T4
(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm

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The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Fig. 1 Apparatus of thermal conductivity of insulating powder

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[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

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Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam

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boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity

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3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.

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8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?

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13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?

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18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

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HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

Aim:

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To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is

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measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:
Sl.

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No.
V I

Fin Temperatures (
0

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C)
Ambient Temp
(
0
C)

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Manometer
Reading
(V)

(A)

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T1 T2 T3 T4 T5 T6 T7 T8
h1
cm
h2

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cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Duct size = 150 mm x 100 mm.

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2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

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Schematic view of the test set-up:



zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5

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10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C
12. Temperature indicator = 0 ? 300

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0
C
(With compensation of ambient temperature up-to 50
0
C)

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13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8

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Brass Pin Fin
Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.

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4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:

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Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.

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4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2

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Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m

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3
/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m

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3

?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s

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2

Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s

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Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

A = area of the duct

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4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.

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(T1 + T6) / 2
o
C
5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number

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6. Nusselt Number:
Nu = CRe
m
(Pr)
0.33

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7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk
m= ?(hp/kA)

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A = area of fin = (? x D
2
) /4
L = Length of the fin
Tw ? average temperature

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T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________

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Heat transfer, Q = ___________ W

Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.


40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer

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6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?

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11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.8

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DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

Aim:

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To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch

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(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water

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between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.

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When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere

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3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg

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8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C
= (or) 0.1 Kcal / kg
0

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C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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11. Temperature indicator digital 0.1
0
C L.C 0 - 200
0

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C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water
Precautions:

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Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4

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? Td
4
)
Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)

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Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

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43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulations:
Proc
edur

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e:
1. H
eat the
water
in the

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tank by
the immersion heater up to a temperature of about 90
0
C.
2. Remove the disc, D before pouring the hot water in the jacket.

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3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.

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6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m

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2
k
4
.

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Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using

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boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

Sl. No.

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Hemisphere Temperature(
0
C) Avg. Temp.
of the
Hemisphere

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(Th)
T4
Steady
Temp. of
Disc

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T0 (Td)
Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number
5. State Wien?s displacement law.

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6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation
10. What are the various modes of condensation?

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11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.9

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DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

Aim:

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To measure emissivity of the test plate surface at various temperature
Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The

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temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.
Specifications:
1. Heater input to black plate W1 = V1 x I1 W

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2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V

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6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300

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0
C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.

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Tabulation:
Sl.
No
Voltage

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Current

Black body
temp(
0

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C)
Avg.
temp.

Polished body

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temp (
0
C)
Avg.
temp.

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Enclosure
Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts

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4
? Ta
4
) A
Eb ? E = (W1 ? W2) / ? (Ts

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4
? Ta
4
) A
E = Eb ? {(W1 ? W2) / ? (Ts

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4
? Ta
4
) A}
Where,

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W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd
2
m

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2

T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)

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Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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? = Stefan boltzman constant = 5.67 x 10
-8
W/m
2
K

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4


Schematic view of the test set-up:

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Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by

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the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

Results:

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The emissivity of the test plate surface is found to be _____________.
Outcome:
From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

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48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Emissivity
2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?

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4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?
6. What is meant by shape factor?
7. Define ? Radiation
8. What is meant by monochromatic emissive power?

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9. Define ? Emissive Power
10. What is meant by absorptivity?
11. Define ? Black Body
12. What is meant by transmissivity?
13. State Plank's distribution law

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14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

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49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.10

EFFECTIVENESS OF PARALLEL / COUNTER

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FLOW HEAT EXCHANGE

Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:

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(i) Experimental Setup
(ii) Stop watch
(iii) Thermometer
Theory:
Heat exchangers are classified in three categories:

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1. Transfer type
2. Storage type
3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.

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The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water

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which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:

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1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50

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0
C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100
0
C - 2 Nos.

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7. Measuring flask = 0 ? 1000 CC

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8. Geyser: single phase type to obtain hot water supply

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9. Thermo Cole insulation for outer pipe.
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Tabulations:

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Sl.
No.
Flow Hot Fluid (
0
C) Cold Fluid (

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0
C)
Time for
collection of
hot fluid

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Kg/sec
Time for
collection
of cold fluid
Kg/sec

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1 Parallel flow
Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)

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1. Area of the pipe A = ? (D ? d) L
Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube
L = Length of the tube

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2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

51 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Where, m = mass flow rate Kg/ sec.

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m = ?v/t, ? = density of water and t = time taken for hot water
Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet
Tho = Temperature of hot water outlet

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3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W
Where, m = mass flow rate
Cp = Specific heat of capacity
Tco = Temperature of cold water inlet
Tci = Temperature of cold water outlet

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4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W
Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)
?Tm = (?Ti - ?To) / In (?Ti/?To)
Where, ?To = Tho ? Tco

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?Ti = Thi ? Tci
6. Over all heat transfer coefficient
h = Q?/?Tm A W/m
2
K

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where Q? = (Qa + Qc) / 2

Procedure:
1. Place the thermometers in position and note down their readings when they are at room temperature and
no water is flowing at either side. This is required to correct the temperature.

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2. Start the flow on hot water side.
3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.
5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.
6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.

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7. Keeping the flow rates same, wait till the steady state conditions are reached.
8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.
10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

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52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Result:
1. The values of effectiveness of heat exchanger were found as

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(i) Parallel flow = ________.
(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)
(i) Parallel flow = ________.
(ii) Counter flow = _________.

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Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow
heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat
exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Heat Exchanger
2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?
4. Write about the merits of drop wise condensation.
5. What is meant by film wise and drop wise condensation?

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6. What is meant by effectiveness?
7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?
9. Distinguish between regenerator and recuperates.
10. What is meant by parallel flow heat exchanger?

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11. What is meant by counter flow heat exchanger?
12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?
Viva ? voce

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53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.11

DETERMINATION OF COP OF A REFRIGERATION

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SYSTEM

Aim:
To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration
system

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Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Experimental setup

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Description:
1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a
reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.
2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated
wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a

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low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the
temperature of chilled water. The above unit is located on the trolley behind front panel.
3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic
expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum
strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure

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gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high
pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy
meter to measure the power consumed either by hater or by compressor.

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54 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
A. A compressor condenser unit placed inside trolley and fitted with
1. R-134a reciprocating compressor
2. Condenser

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3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan
4. A receiver with angle check valve
B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity
placed inside a well insulated wooden box and provided with
5. Evaporator coil

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6. Stirrer
7. Electric heater 230 V, A.C.
8. The sensing bulb of low temperature thermostat.
9. A high temperature thermostat.
10. A Thermometer to measure the chilled water temperature

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C. The front panel on which are mounted the following
11. Capillary expansion tube with isolating valve.
12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator
and isolating valve
13. Drier cum strainer and sight glass

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14. Thermostat at inlet and outlet of both evaporator and condenser
15. Pressure gauge at inlet and outlet of evaporator and condenser
16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out
17. Heat power regulator switch and regulator
18. Energy meter to measure the power consumed either by hater or by compressor.

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55 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.
2. The heater regulator should be switched off whenever not in use. Heating water beyond 40
0
C may lead to

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permanent damage of the entire system. A high temperature cut off thermostat is provided in the water
chiller, to cut off the heater beyond 30
0
C.Check the setting of the same before operation.
3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.

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4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.
5. The solenoid thermostat is adjusted to cut at 15
0
C and cut in at 10
0

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C of the chilled water. Do not alter the
same.
6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.
7. The space near the condenser should permit good ventilation to aid proper fan performance.
8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked

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in
0
F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,
calibrated in SI units, are not available.)
9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to

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obtain the pressure in MN/m
2
.e.g. P = x psig
= (x + 14.7) psia
= (x + 14.7) / 145 MN/m

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2
(MPa)
10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.
Formulae used:
Let, State 1 indicates the entry of compressor.

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State 2 indicates the exit of compressor.
State 3 indicates the exit from condenser.
State 4 indicates the entry to evaporator
P = Pressure (bar)
T = Temperature (

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0
C)
H = Specific enthalpy (kJ/kg)
v = Specific Volume (m
3

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/Kg)
n = Number of revolutions of energy meter disc.
t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)
t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)
K = Energy meter constant = 3200 lmp / kWh

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N = Speed of compressor = 2840 rpm
h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

56 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2
h3 = Specific enthalpy at Pc and T3 (kJ/kg)
h4 = h3
Stroke volume of compressor = (?/ 4) d
2

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l = 12.58 x 10
-6
m
3

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1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar
2. Average condenser pressure, Pc = (P2 + P3) / 2 bar
3. Heater input, Qe = (n / t1) x (3600 / k) kW
4. Compressor input, W = (n / t2) x (3600 / k) kW
5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1

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6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)
7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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57 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I


Sl.

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No.

Initial
Temp.
of water

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Final
Temp.
of water
Duration

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of exp.

Delivery
pressure

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Delivery
Temp.

Condense
Outlet

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Pressure

Condense
Outlet
Temp.

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Pressure
after
throttling

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Temp.
After
Throttli
ng

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Suction
pressur
e
Suction

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Temp.

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Time for
10 rev. of
compress
or energy
meter

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Height
of water

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in the
vessel

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58 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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Load Test with Capillary tube as expansion device:
1. Fill the chilled water calorimeter with pure water so that the evaporative coils are
fully immersed.
2. Select the capillary tube line by opening the shut-off valve on this line and closing
the one on the thermostatic expansion valve line. The solenoid switch is switched OFF.

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3. Start the compressor and run for some time so that the chilled water temperature
is lowered to the given test temperature.
4. Switch on the heater and slowly increase the power.
5. Allow The temperature in water calorimeter to reach the equilibrium
temperature.

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6. Connect energy meter to motor and heater by the selector switch one after another
and note down the time taken for 10 pulses of the energy meter disc.
7. Note down the pressure and temperature readings at locations 1,2,3 & 4 as
mentioned.
8. Switch OFF the heater and the mains.

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Result:
The load test on a refrigeration test rig was conducted and the results are as follows.
1. Actual C.O.P. of the system =____________.
2. Rhetorical C.O.P. of the system = ___________.
3. Volumetric Efficiency = ___________.

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Outcome:
From this experiment, conducting the load test on a refrigeration test rig and finding out the
volumetric efficiency and co-efficient of performance for any type of refrigerant is learnt and this experiment
could be used in the areas such as Refrigerator and Air Conditioning.

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Applications:
Refrigerator, Air Conditioning.

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59 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? COP
2. Which thermodynamic cycle is used in air conditioning of airplanes using air as refrigerant?
3. Define ? Ton of Refrigeration
4. What is meant by refrigeration?
5. What is meant by air conditioning?

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6. What are the four important properties of a good refrigerant?
7. How does the actual vapour compression cycle differ from that of the ideal cycle?
8. Name any four commonly used refrigerants.
9. What are the expansion devices used in a vapour compression plant?
10. Why throttle valve is used in place of expansion cylinder for vapour compression refrigerant machine?

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11. What are the merits of air refrigeration system?
12. What are the demerits of air refrigeration system?
13. Define ? Refrigerant
14. What is net refrigerating effect of the refrigerant?
15. What are the methods to obtain sub cooling of refrigerant?

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Viva ? voce

60 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.12 EXPERIMENTS ON PSYCHROMETRIC PROCESS

Aim:
To conduct an experiment on psychrometric processes with air conditioning system
Apparatus required:

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(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Digital anemometer
(v) Experimental setup

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Description:
The test rig consist of
1. An air duct support of stand
2. A blower to set up air flow through the duct along with a speed control to vary the
velocity of air.

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3. A heater to rise the air temperature with regulator and energy meter.
4. Water spray, collecting tray, reservoir with gauge pump.
5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.
(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after cooling coil).
6. The test rig consist of compressor, condenser unit placed inside trolley and fitted

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with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for
condenser and (iv) Liquid receiver.
7. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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61 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I

Precautions:
1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence

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avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kw only for the motor
circuit.
2. Natural air currents in the room if in the direction of air duct may defect the experimental results and
hence the duct should be placed such that no wind from doors, windows, fan and cooling air from
other test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan

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and should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase
beyond 240 psi.
3. Never exceed dry bulb temperatures of 40
0
C after the heater (station 2) otherwise the air duct may be

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damaged.
4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may
exceed its maximum of 32
0
C and calibration may be affected.

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5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not
running this will lead to rise in temperature at the heater and may damage the heater and the air duct.
6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their
duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.
7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer

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is placed inside the reservoir at the top. This may have to the cleaned when necessary.
8. Do not open the gate valve fully otherwise water may be splashed outside and the waster
measurement may be in error.
S.
N

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o
Inlet temp
Outlet
temp
Pressu

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re
P1
Tem
p.
T1

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Pressu
re
P2
Temp.
T2

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Pressu
re
P3

Tem

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p.
T3


Pressu

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re
P4


Temp.

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T4
Energy
for 10
revolutio
ns

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Twet Tdry Twet Tdry Lb/in
o
C Lb/in
o
C Lb/in

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o
C Lb/in
o
C

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62 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

9. If the low pressure cut out comes in to action, it means that the Freon charge is insufficient and may
have to be filled up. The suction pressure should never go below 2 psi as otherwise the compressor

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seals will be damaged and air and moisture may enter the system.
10. The refrigerant strainer placed on the front panel should always be warm. If it cools and moisture
condenser on it, then the strainer might have to be charged by an experienced refrigeration
mechanics.
11. The refrigerating system can work continuously for 2 hours, however if the room temperature is above

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25
0
C the condenser may be heated up and the delivery pressure may rise. Do not exceed 240 psi.
Pour one or two glasses of drinking water over the fins of the condenser in order to reduce the
delivery pressure.

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12. After some months of operation the compressor may have to be topped up with oil and some quantity
of Freon-22 may have to be charged by an experienced mechanics.
13. See that distilled water is filled up in the plastic dishes provided under the wet bulb thermometers and
that the wicks are in tact otherwise erroneous readings may be obtained. These thermometers will
show correct readings only when the fan is in operation.

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14. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

Formulae used:
1. Corresponding to the dry and wet bulb temperature at all the stations obtain the specific enthalpy and

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specific humidity values from psychrometric chart.
i.e., h1 and w1 at tb1 and tw1 and so on.
2. Air flow rate, ma = (A x V) / v4 Kg / sec
Where, A = Area of duct at outlet in m
2

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(0.46 m x 0.086 m)
V = Air velocity ( m / sec)
V4 = Specific volume of moist air at station 4 using psychometric chart m
3
/Kg

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3. Moisture added from psychrometric chart, mw1 = ma (w3-w2) Kg / sec.
Where, w3 = Specific humidity at station 3
w2 = Specific humidity at station 2
4. Cooling effect produced on air, Qe = ma (h3 ? h4) kW.
Where, h3 = Specific enthalpy at state 3 kJ/kg

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h4 = Specific enthalpy at state 4 kJ/kg
5. Moisture condensed, mcl = ma (w3 ? w4) kg/sec
Where, w3 = Specific humidity at station 3
w4 = Specific humidity at station 4

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63 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Fill water in the wet bulb temperature probe trays.
2. Start the main.

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3. Start the blower and run it the required speed by keeping the speed regulator at
position.
4. Start the spray pump and open the gate valve suitably.
5. Start the heater.
6. Select the expansion device (Capillary tube / Thermostatic expansion valve)

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7. Start the cooling compressor.
8. Wait for some time till thermometers shown practically constant readings and note down the
following readings:
(i) Dry bulb temperatures tdb1, tdb2, tdb3, tdb4.
(ii) Wet bulb temperatures twb1, twb2, twb3, twb4.

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(iii) Spray water temperature, ts
(iv) Surface temperature of cooler, tm ( at control panel)
(v) Pressure gauge reading, pd ( at control panel)
(vi) Compound gauge reading, Ps ( at control panel)
(vii) Level reduction?l? in spray reservoir (mm) during 5 min.

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(viii) Amount of condensate collected ?lc?, in a measuring jar at cooler tray during a
run of 5 minutes at constant conditions.
(ix) Time in second ?SH? for 10 pulses of the energy meter disc connected to the
heater.
(x) Time in seconds Sc for 10 pulses of the energy meter disc connected to cooler

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compressor.
Result:
Experiment on psychrometric processes with air conditioning system was drawn
Outcome:
From this experiment, conducting the test on psychrometric processes with air

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conditioning system is learnt and this experiment could be used in all types of air conditioning systems.

Applications:
Air Conditioning.

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64 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the commonly used unit of refrigeration?
2. Distinguish between summer air conditioning and winter air conditioning.
3. Define ? RSHF Line
4. Define ? By Pass Factor of a Heating Coil

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5. What is the effect of sub cooling a refrigerant in a vapour compression cycle?
6. What is the function of analyzer and rectifier in an absorption system?
7. What is the purpose of generator assembly in vapour absorption refrigeration system?
8. State the substance used in the Lithium Bromide system and their functions.
9. Differentiate wet compression from dry compression.

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10. Define ? Apparatus Dew Point
11. What is meant by dew point temperature?
12. Define ? Wet Bulb Temperature
13. Define ? Degree of Saturation
14. What is meant by specific humidity?

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15. Define ? Relative Humidity

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Viva ? voce

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65 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.13

PERFORMANCE TEST ON A RECIPROCATING

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AIR COMPRESSOR

Aim:
To conduct a load test on the 2 - stage reciprocating air compressor to determine the isothermal and
volumetric Efficiencies at various delivery pressures

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Apparatus required:
* Air compressor with accessories.
* Stop watch.
Description:

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Two stage air compressors is a reciprocating type driven by a prime mover. The test rig consist of a base on
which the tank is mounted. The outlet of the compressor is connected to the receiver. The suction is
connected to air tank with a calibrated orifice plate through a water manometer. The input to the motor is
recorded by an energy meter. The temperature and pressure of the air compressed is indicated by a
thermometer and pressure gauge.

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Specifications:
1. Air compressor:
* LP Bore, DLP = 63.0 mm.
* HP Bore, DHP = 79.0 mm.
* Stroke, L = 80.0 mm.

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* Speed, N = 1440 rpm (5 HP)
* Effective radius = 0.193 m
2. Air receiver capacity = 0.33 m3
3. Orifice, diameter, d0 = 12 mm
4. Orifice area,. A0 : ?d0

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2
/ 4 = ----------- m
2

5. Coefficient of discharge C d. = 0.6

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6. Energy-meter constant = 200 rev / kWh

66 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

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Observation Table: II
Sl.
No.
Actual

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Discharge
Va
Theoritical
Discharge
Vt

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Volumetric
Efficiency
?
Power
Input

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Output
Power

Overall

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Efficiency
?0
Isothermal
Workdone
IwD

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Polytropic
Workdone
PwD
Isothermal
Efficiency

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?iso
m
3
/sec m
3

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/sec % kW kW % J/Kg J/Kg %


Sl.
No.

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Pressure
p
Manometer
h1
Manometer

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h2
Time for 5 revolutions Energy meter Speed of the compressor Temperature
T1
Temperature
T1

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Kg/cm
2
Cm cm sec rpm
o
C

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o
C

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67 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Check whether manometer is filled with water up to the required level.
2. The maximum pressure in the receiver tank should not exceed 12 kg / cm

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2

Procedure:
1. Ensure that gauge pressure in the tank is zero.
2. Start the compressor. Read the receiver pressure gauge for a particular pressure.

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3. Maintain the pressure constant by adjusting the outlet valve.
4. Note down the manometer reading and time taken for 3 revolution of the energy
Formulae used:
1. Density of air at RTP:
? RTP = ? NTP X 273 Kg/ m

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3

(273 + Room Temp)
Where density of air at NTP = 1.293 Kg/ m
3

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.

2. Air head causing flow:
ha RTP = (h1 - h2) x ? water m
?a RTP

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Where,
(h1- h2) = Difference in manometer liquid, in m.

3. Actual volume at RTP:
Va RTP = C.d x Ao x ? 2 g ha RTP

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Where,
C d= Coefficient of discharge = 0.6.
A o = Area of orifice = ?(d0)
2
m

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2
.
4
Diameter of orifice d o = 0.01 m.
4. Actual volume at NTP:

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Va NTP = VaRTP x T NTP
T RTP
Where,
T NTP = Normal temp - 273
o

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k
T RTP = Room temp -
o
c (273 + TROOM )

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68 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

5. Theoretical Volume of air: (at intake conditions)
V T = ?D
2

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x L x Nc m
3
/ sec.
4 x 60
D = LP Bore diameter = 88.5 mm.

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L = Stroke length = 88.9 mm.
Nc = Compressor speed rpm.
6. Volumetric Efficiency:(for LP stage)
?vol = Va NTP x 100%
Vt

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7. Shaft Input through Energy meter:

= 1 x n x ?t x ?m x 3600 kw.
( Ec x t )
Where,

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Ec = Energy meter constant = 200 rev / kWh
?t = Efficiency for transmission = 0.95.
? m = Efficiency for motor = 0.90.
t = Time for 'n' revolution of energy meter disc.
n = no. of rev. of Energy meter disc.

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8. Isothermal power:
= Pa x Va RTP x log e (R) W
1000
Pa = Atmospheric pressure in N/ m

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2
= 1.01325 x 10
5
N / m
2

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.
R = (Pressure gauge reading + atmospheric pressure)
atmospheric pressure.
9. Isothermal efficiency:
? ISO = Isothermal power x 100%

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Shaft input

Result:
The values of isothermal and volumetric efficiency at various delivery pressures have been studied &
graph between Pressure Vs Volumetric efficiency and Pressure Vs Isothermal efficiency are drawn.

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69 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Outcome:

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From this experiment, conducting the load test on two stage reciprocating air compressor for
determining the isothermal and volumetric Efficiencies at various delivery pressures is understood and this
experiment could be used in the areas such as Refrigerator, Air Conditioning, IC engines, etc.

Applications:

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Refrigerator, Air Conditioning, IC engines.


1. How are air compressors classified?
2. Define ? Isothermal Efficiency of Air Compressor

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3. What is meant by FAD (Free Air Delivery)?
4. What is meant by perfect inter-cooling?
5. Define ? Clearance Ratio of an Air Compressor
6. List out the applications of compressed air.
7. What are the types of air compressors?

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8. What is meant by single acting compressor?
9. What is meant by double acting compressor?
10. What is meant by single stage compressor?
11. What is meant by multi stage compressor?
12. Indicate the applications of reciprocating compressors in industry>

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13. Define ? Mechanical Efficiency
14. What is meant by compression ratio?
15. What are the factors that affect the volumetric efficiency of a reciprocating compressor?

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Viva ? voce

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70 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.14

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PERFORMANCE TEST IN A HC REFRIGERATION
SYSTEM


Aim:

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To conduct the performance test on Vapour Compression Refrigeration System and to determine the
Coefficient of Performance using solenoid valve by throttling method

Description:

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In this system the working fluid is a HC out of a refrigeration system. The HC compression system is most
important system from the view point of commercial and domestic utility. The HC refrigerant at low temp and
pressure enters the reciprocating compressor, where it is compressed isentropically and subsequently its temp
and pressure increases considerably. This HC after leaving the compressor enters the condenser where it is

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cooled into low temperature. Then it is sucked by reciprocating compressor and is thus repeated.
Formula used:

Actual COP = refrigerant effect
I/p energy to compressor

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Refrigerant effect = mxCpx ? T
t
m - mass of water (kg)
Cp - Sp. Heat of water (4.2 kJ/kg K)
?T ? decrease in temp (Ti-Ts)

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t - timetaken duration of expt (sec)

Energy input =n x 3600 /k x t
n ? number of revolutions in energy meter
t ? time taken of ?n? revolutions

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k ? energy meter constant (3200)

FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION

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MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex

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software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills

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4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning

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To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the

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career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society

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7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with

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coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:

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HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube

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5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface

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10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes

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13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.

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4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system

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13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES

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CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6

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2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3

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Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5

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Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7

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Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS

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11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68

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15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT

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USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate

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assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The

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heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:

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1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2

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Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently

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5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm

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2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm

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7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100
0

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C
9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm

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11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A

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16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C

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19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter
V
Ammeter

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A
Main heater (
0
C) Test Plate (
0

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C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.

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Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.

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4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.

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4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?

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9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?

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14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?

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19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF

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PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus

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Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter

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(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm

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5. The effective length of the above = 500 mm

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Precautions:

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1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W

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Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material

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k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.

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No.
Voltage
(V)
Current
(A)

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Heater Temperature
(
0
C)
Asbestos Temperature

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(
0
C)
Saw dust
Temperature (

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0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.

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2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.

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6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.

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The thermal conductivity of resistive material = _________________ W /m
2
-K

Outcome:

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From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:

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Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. Define ? Nusselt Number(Nu)

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2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)

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7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?

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12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?

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17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION

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FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection

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Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter

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Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The

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temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold

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fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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Schematic view of the test set-up:
mm

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mm

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Specifications:

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1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.

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5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A

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7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

Tabulation:

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Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m

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2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (

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0
C) ?
2. hL / k = A { g L
3
?T Cp ?/2v

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2
}
n

Where, hL / k are called Nusselt Number.

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L
3
g?T / v
2
is called Grashof number.

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?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid

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? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta

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For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)

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0.25
for 10
4
< Gr.Pr.<10
8

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hL / k = 0.13 (Gr.Pr)
1/3
for 10
8

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< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.

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4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as

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Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m
2

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K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC

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engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?

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6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?

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11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.

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16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to

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the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

Sl. No. Voltage Current Temperature in (
0

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C)
Manometer
reading of water
in h in meter

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(V) (A)
T1

T2

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T3

T4

T5

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T6

h1
cm

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h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer

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6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0
C
(Calibrated for chromel alumel thermocouple)

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8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.

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7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat

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input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)

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Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o
C)

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= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di

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2
?2gH x (?w / ?a) m
3
/hr
3. ha = qa /A(Ts- Ta) W / m

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2
K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

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Ta = Average temperature of air = (T1 + T6)/2
o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4

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o
C
Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m

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3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

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d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

using this procedure obtain the value of ?ha? for different air flow rate

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4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2
)/4]

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v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o
C
5. Nusselt Number:

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Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

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27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m

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2

k = Thermal conductivity of fluid W/m
2
K

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Nu = 0.023 (Re)
0.8
(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

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Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m

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2
K
htheoritical = -------------- W/m
2
K

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Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?

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4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?

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9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.

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14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

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29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

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Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the

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thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The

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temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is

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the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm

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3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat

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input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

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30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.

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7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow

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R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:

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Sl.No. Voltmeter
reading
(V)
Ammeter
reading

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(A)
T1
(
0
C)

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T2
(
0
C)
T3

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(
0
C)
T4
(

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0
C)
T5
(
0

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C)
T6
(
0
C)

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T7
(
0
C)
T8

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(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Composite wall apparatus set-up

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Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

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Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal

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conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?

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10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

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33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY

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OF INSULATING POWDER

Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

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The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit

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is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

Procedure:

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1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter

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reading( V)
Ammeter
reading (A)
T1
(

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0
C)
T2
(
0

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C)
T3
(
0
C)

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T4
(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1

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Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.


34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Fig. 1 Apparatus of thermal conductivity of insulating powder

[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater

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control]

Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

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Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to

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be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?

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4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?

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9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)

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14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?

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19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

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36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

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HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:

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A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is

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shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:
Sl.
No.

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V I

Fin Temperatures (
0
C)

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Ambient Temp
(
0
C)
Manometer

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Reading
(V)

(A)

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T1 T2 T3 T4 T5 T6 T7 T8
h1
cm
h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm

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3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.

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11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C
12. Temperature indicator = 0 ? 300
0

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C
(With compensation of ambient temperature up-to 50
0
C)
13. Dimmer stat for heat input controls 230 V, 2 A

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14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8
Brass Pin Fin

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Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

16. Ammeter = 0 ? 2 A

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.

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5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:
Forced Convection:

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1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient

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temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)

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Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m
3

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/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m
3

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?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s
2

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Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

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A = area of the duct
4. Reynold?s Number:

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Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2

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o
C
5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number
6. Nusselt Number:

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Nu = CRe
m
(Pr)
0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)

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h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk
m= ?(hp/kA)
A = area of fin = (? x D

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2
) /4
L = Length of the fin
Tw ? average temperature
T? ? ambient (surface) temperature (T6)

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8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

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Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through

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pin-fin is to be found.


40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Extended Surface

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2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer
6. Define ? Fin Efficiency

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7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?
11. Define ? Convection

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12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

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41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.8

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DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus

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Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Geyser water

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Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to

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measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response

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of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm

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4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg

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0
C
= (or) 0.1 Kcal / kg
0
C

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9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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11. Temperature indicator digital 0.1
0
C L.C 0 - 200
0
C with built-in cold junction compensation and a timer set

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for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically

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there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4
? Td

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4
)
Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0

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dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:
Proc
edur
e:

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1. H
eat the
water
in the
tank by

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the immersion heater up to a temperature of about 90
0
C.
2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.

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4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate

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thermocouple).

Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m
2

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k
4
.

Outcome:

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From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.

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.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

Sl. No.
Hemisphere Temperature(

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0
C) Avg. Temp.
of the
Hemisphere
(Th)

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T4
Steady
Temp. of
Disc
T0 (Td)

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Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]

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2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number
5. State Wien?s displacement law.
6. What is the significance of Biot Number?

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7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation
10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]

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12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

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45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.9

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DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

Aim:
To measure emissivity of the test plate surface at various temperature

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:

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The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp

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black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.
Specifications:
1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W

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3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A

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7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300
0

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C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Use proper voltage range on Voltmeter.

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3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.
Tabulation:

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Sl.
No
Voltage

Current

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Black body
temp(
0
C)

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Avg.
temp.

Polished body
temp (

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0
C)
Avg.
temp.

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Enclosure
Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts
4

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? Ta
4
) A
Eb ? E = (W1 ? W2) / ? (Ts
4

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? Ta
4
) A
E = Eb ? {(W1 ? W2) / ? (Ts
4

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? Ta
4
) A}
Where,
W1 = Heater input to black plate = V1 x I1 W

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W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd
2
m
2

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T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)
Eb = Emissivity of black plate = 1

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E = Emissivity of Test plate

47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

? = Stefan boltzman constant = 5.67 x 10

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-8
W/m
2
K
4

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Schematic view of the test set-up:

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Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by
the dimmer stat so that the two plates will be maintained at the same temperature.

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3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

Results:
The emissivity of the test plate surface is found to be _____________.

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Outcome:
From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

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48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Emissivity
2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?
4. State Lambert?s cosine law.

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5. What is the purpose of radiation shield?
6. What is meant by shape factor?
7. Define ? Radiation
8. What is meant by monochromatic emissive power?
9. Define ? Emissive Power

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10. What is meant by absorptivity?
11. Define ? Black Body
12. What is meant by transmissivity?
13. State Plank's distribution law
14. What is meant by gray body?

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15. Define ? Irradiation

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Viva ? voce

49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.10

EFFECTIVENESS OF PARALLEL / COUNTER
FLOW HEAT EXCHANGE

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Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:
(i) Experimental Setup

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(ii) Stop watch
(iii) Thermometer
Theory:
Heat exchangers are classified in three categories:
1. Transfer type

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2. Storage type
3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.
The transfer type exchangers are further classified accordant to flow arrangements as:

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i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water
which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water

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flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:
1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm

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2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50
0

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C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100
0
C - 2 Nos.
7. Measuring flask = 0 ? 1000 CC

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50 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

8. Geyser: single phase type to obtain hot water supply
9. Thermo Cole insulation for outer pipe.

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Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Tabulations:
Sl.

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No.
Flow Hot Fluid (
0
C) Cold Fluid (
0

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C)
Time for
collection of
hot fluid
Kg/sec

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Time for
collection
of cold fluid
Kg/sec
1 Parallel flow

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Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)
1. Area of the pipe A = ? (D ? d) L

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Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube
L = Length of the tube

2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

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51 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Where, m = mass flow rate Kg/ sec.
m = ?v/t, ? = density of water and t = time taken for hot water

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Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet
Tho = Temperature of hot water outlet

3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W

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Where, m = mass flow rate
Cp = Specific heat of capacity
Tco = Temperature of cold water inlet
Tci = Temperature of cold water outlet
4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W

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Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)
?Tm = (?Ti - ?To) / In (?Ti/?To)
Where, ?To = Tho ? Tco
?Ti = Thi ? Tci

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6. Over all heat transfer coefficient
h = Q?/?Tm A W/m
2
K
where Q? = (Qa + Qc) / 2

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Procedure:
1. Place the thermometers in position and note down their readings when they are at room temperature and
no water is flowing at either side. This is required to correct the temperature.
2. Start the flow on hot water side.

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3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.
5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.
6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.
7. Keeping the flow rates same, wait till the steady state conditions are reached.

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8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.
10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Result:
1. The values of effectiveness of heat exchanger were found as
(i) Parallel flow = ________.

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(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)
(i) Parallel flow = ________.
(ii) Counter flow = _________.

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Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow
heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat
exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.
Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.



1. Define ? Heat Exchanger

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2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?
4. Write about the merits of drop wise condensation.
5. What is meant by film wise and drop wise condensation?
6. What is meant by effectiveness?

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7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?
9. Distinguish between regenerator and recuperates.
10. What is meant by parallel flow heat exchanger?
11. What is meant by counter flow heat exchanger?

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12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?
Viva ? voce

53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.11

DETERMINATION OF COP OF A REFRIGERATION
SYSTEM

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Aim:
To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration
system
Apparatus required:

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(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Experimental setup
Description:

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1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a
reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.
2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated
wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a
low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the

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temperature of chilled water. The above unit is located on the trolley behind front panel.
3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic
expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum
strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure
gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high

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pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy
meter to measure the power consumed either by hater or by compressor.

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54 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
A. A compressor condenser unit placed inside trolley and fitted with
1. R-134a reciprocating compressor
2. Condenser
3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan

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4. A receiver with angle check valve
B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity
placed inside a well insulated wooden box and provided with
5. Evaporator coil
6. Stirrer

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7. Electric heater 230 V, A.C.
8. The sensing bulb of low temperature thermostat.
9. A high temperature thermostat.
10. A Thermometer to measure the chilled water temperature
C. The front panel on which are mounted the following

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11. Capillary expansion tube with isolating valve.
12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator
and isolating valve
13. Drier cum strainer and sight glass
14. Thermostat at inlet and outlet of both evaporator and condenser

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15. Pressure gauge at inlet and outlet of evaporator and condenser
16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out
17. Heat power regulator switch and regulator
18. Energy meter to measure the power consumed either by hater or by compressor.

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55 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:

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1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.
2. The heater regulator should be switched off whenever not in use. Heating water beyond 40
0
C may lead to
permanent damage of the entire system. A high temperature cut off thermostat is provided in the water

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chiller, to cut off the heater beyond 30
0
C.Check the setting of the same before operation.
3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.
4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.

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5. The solenoid thermostat is adjusted to cut at 15
0
C and cut in at 10
0
C of the chilled water. Do not alter the

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same.
6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.
7. The space near the condenser should permit good ventilation to aid proper fan performance.
8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked
in

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0
F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,
calibrated in SI units, are not available.)
9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to
obtain the pressure in MN/m

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2
.e.g. P = x psig
= (x + 14.7) psia
= (x + 14.7) / 145 MN/m
2

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(MPa)
10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.
Formulae used:
Let, State 1 indicates the entry of compressor.
State 2 indicates the exit of compressor.

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State 3 indicates the exit from condenser.
State 4 indicates the entry to evaporator
P = Pressure (bar)
T = Temperature (
0

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C)
H = Specific enthalpy (kJ/kg)
v = Specific Volume (m
3
/Kg)

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n = Number of revolutions of energy meter disc.
t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)
t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)
K = Energy meter constant = 3200 lmp / kWh
N = Speed of compressor = 2840 rpm

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h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

56 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2

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h3 = Specific enthalpy at Pc and T3 (kJ/kg)
h4 = h3
Stroke volume of compressor = (?/ 4) d
2
l = 12.58 x 10

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-6
m
3

1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar

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2. Average condenser pressure, Pc = (P2 + P3) / 2 bar
3. Heater input, Qe = (n / t1) x (3600 / k) kW
4. Compressor input, W = (n / t2) x (3600 / k) kW
5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1
6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)

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7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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57 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I


Sl.
No.

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Initial
Temp.
of water

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Final
Temp.
of water
Duration
of exp.

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Delivery
pressure

Delivery

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Temp.

Condense
Outlet
Pressure

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Condense
Outlet
Temp.

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Pressure
after
throttling

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Temp.

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After
Throttli
ng

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Suction
pressur
e
Suction
Temp.

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Time for

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10 rev. of
compress
or energy
meter

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Height
of water
in the

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vessel

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58 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
Load Test with Capillary tube as expansion device:

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1. Fill the chilled water calorimeter with pure water so that the evaporative coils are
fully immersed.
2. Select the capillary tube line by opening the shut-off valve on this line and closing
the one on the thermostatic expansion valve line. The solenoid switch is switched OFF.
3. Start the compressor and run for some time so that the chilled water temperature

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is lowered to the given test temperature.
4. Switch on the heater and slowly increase the power.
5. Allow The temperature in water calorimeter to reach the equilibrium
temperature.
6. Connect energy meter to motor and heater by the selector switch one after another

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and note down the time taken for 10 pulses of the energy meter disc.
7. Note down the pressure and temperature readings at locations 1,2,3 & 4 as
mentioned.
8. Switch OFF the heater and the mains.
Result:

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The load test on a refrigeration test rig was conducted and the results are as follows.
1. Actual C.O.P. of the system =____________.
2. Rhetorical C.O.P. of the system = ___________.
3. Volumetric Efficiency = ___________.

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Outcome:
From this experiment, conducting the load test on a refrigeration test rig and finding out the
volumetric efficiency and co-efficient of performance for any type of refrigerant is learnt and this experiment
could be used in the areas such as Refrigerator and Air Conditioning.
Applications:

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Refrigerator, Air Conditioning.

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59 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? COP

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2. Which thermodynamic cycle is used in air conditioning of airplanes using air as refrigerant?
3. Define ? Ton of Refrigeration
4. What is meant by refrigeration?
5. What is meant by air conditioning?
6. What are the four important properties of a good refrigerant?

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7. How does the actual vapour compression cycle differ from that of the ideal cycle?
8. Name any four commonly used refrigerants.
9. What are the expansion devices used in a vapour compression plant?
10. Why throttle valve is used in place of expansion cylinder for vapour compression refrigerant machine?
11. What are the merits of air refrigeration system?

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12. What are the demerits of air refrigeration system?
13. Define ? Refrigerant
14. What is net refrigerating effect of the refrigerant?
15. What are the methods to obtain sub cooling of refrigerant?

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Viva ? voce

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60 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.12 EXPERIMENTS ON PSYCHROMETRIC PROCESS

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Aim:
To conduct an experiment on psychrometric processes with air conditioning system
Apparatus required:
(i) Thermometer

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(ii) Electric Heater
(iii) Stop watch
(iv) Digital anemometer
(v) Experimental setup
Description:

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The test rig consist of
1. An air duct support of stand
2. A blower to set up air flow through the duct along with a speed control to vary the
velocity of air.
3. A heater to rise the air temperature with regulator and energy meter.

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4. Water spray, collecting tray, reservoir with gauge pump.
5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.
(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after cooling coil).
6. The test rig consist of compressor, condenser unit placed inside trolley and fitted
with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for

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condenser and (iv) Liquid receiver.
7. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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61 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I

Precautions:
1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence
avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kw only for the motor

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circuit.
2. Natural air currents in the room if in the direction of air duct may defect the experimental results and
hence the duct should be placed such that no wind from doors, windows, fan and cooling air from
other test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan
and should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase

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beyond 240 psi.
3. Never exceed dry bulb temperatures of 40
0
C after the heater (station 2) otherwise the air duct may be
damaged.

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4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may
exceed its maximum of 32
0
C and calibration may be affected.
5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not

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running this will lead to rise in temperature at the heater and may damage the heater and the air duct.
6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their
duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.
7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer
is placed inside the reservoir at the top. This may have to the cleaned when necessary.

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8. Do not open the gate valve fully otherwise water may be splashed outside and the waster
measurement may be in error.
S.
N
o

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Inlet temp
Outlet
temp
Pressu
re

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P1
Tem
p.
T1
Pressu

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re
P2
Temp.
T2
Pressu

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re
P3

Tem
p.

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T3


Pressu
re

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P4


Temp.
T4

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Energy
for 10
revolutio
ns
Twet Tdry Twet Tdry Lb/in

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o
C Lb/in
o
C Lb/in
o

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C Lb/in
o
C

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62 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

9. If the low pressure cut out comes in to action, it means that the Freon charge is insufficient and may
have to be filled up. The suction pressure should never go below 2 psi as otherwise the compressor
seals will be damaged and air and moisture may enter the system.

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10. The refrigerant strainer placed on the front panel should always be warm. If it cools and moisture
condenser on it, then the strainer might have to be charged by an experienced refrigeration
mechanics.
11. The refrigerating system can work continuously for 2 hours, however if the room temperature is above
25

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0
C the condenser may be heated up and the delivery pressure may rise. Do not exceed 240 psi.
Pour one or two glasses of drinking water over the fins of the condenser in order to reduce the
delivery pressure.
12. After some months of operation the compressor may have to be topped up with oil and some quantity

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of Freon-22 may have to be charged by an experienced mechanics.
13. See that distilled water is filled up in the plastic dishes provided under the wet bulb thermometers and
that the wicks are in tact otherwise erroneous readings may be obtained. These thermometers will
show correct readings only when the fan is in operation.
14. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and

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corrosion damage.

Formulae used:
1. Corresponding to the dry and wet bulb temperature at all the stations obtain the specific enthalpy and
specific humidity values from psychrometric chart.

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i.e., h1 and w1 at tb1 and tw1 and so on.
2. Air flow rate, ma = (A x V) / v4 Kg / sec
Where, A = Area of duct at outlet in m
2
(0.46 m x 0.086 m)

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V = Air velocity ( m / sec)
V4 = Specific volume of moist air at station 4 using psychometric chart m
3
/Kg
3. Moisture added from psychrometric chart, mw1 = ma (w3-w2) Kg / sec.

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Where, w3 = Specific humidity at station 3
w2 = Specific humidity at station 2
4. Cooling effect produced on air, Qe = ma (h3 ? h4) kW.
Where, h3 = Specific enthalpy at state 3 kJ/kg
h4 = Specific enthalpy at state 4 kJ/kg

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5. Moisture condensed, mcl = ma (w3 ? w4) kg/sec
Where, w3 = Specific humidity at station 3
w4 = Specific humidity at station 4

63 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Fill water in the wet bulb temperature probe trays.
2. Start the main.
3. Start the blower and run it the required speed by keeping the speed regulator at

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position.
4. Start the spray pump and open the gate valve suitably.
5. Start the heater.
6. Select the expansion device (Capillary tube / Thermostatic expansion valve)
7. Start the cooling compressor.

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8. Wait for some time till thermometers shown practically constant readings and note down the
following readings:
(i) Dry bulb temperatures tdb1, tdb2, tdb3, tdb4.
(ii) Wet bulb temperatures twb1, twb2, twb3, twb4.
(iii) Spray water temperature, ts

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(iv) Surface temperature of cooler, tm ( at control panel)
(v) Pressure gauge reading, pd ( at control panel)
(vi) Compound gauge reading, Ps ( at control panel)
(vii) Level reduction?l? in spray reservoir (mm) during 5 min.
(viii) Amount of condensate collected ?lc?, in a measuring jar at cooler tray during a

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run of 5 minutes at constant conditions.
(ix) Time in second ?SH? for 10 pulses of the energy meter disc connected to the
heater.
(x) Time in seconds Sc for 10 pulses of the energy meter disc connected to cooler
compressor.

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Result:
Experiment on psychrometric processes with air conditioning system was drawn
Outcome:
From this experiment, conducting the test on psychrometric processes with air
conditioning system is learnt and this experiment could be used in all types of air conditioning systems.

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Applications:
Air Conditioning.

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64 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the commonly used unit of refrigeration?
2. Distinguish between summer air conditioning and winter air conditioning.
3. Define ? RSHF Line
4. Define ? By Pass Factor of a Heating Coil
5. What is the effect of sub cooling a refrigerant in a vapour compression cycle?

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6. What is the function of analyzer and rectifier in an absorption system?
7. What is the purpose of generator assembly in vapour absorption refrigeration system?
8. State the substance used in the Lithium Bromide system and their functions.
9. Differentiate wet compression from dry compression.
10. Define ? Apparatus Dew Point

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11. What is meant by dew point temperature?
12. Define ? Wet Bulb Temperature
13. Define ? Degree of Saturation
14. What is meant by specific humidity?
15. Define ? Relative Humidity

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Viva ? voce

65 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.13

PERFORMANCE TEST ON A RECIPROCATING
AIR COMPRESSOR

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Aim:
To conduct a load test on the 2 - stage reciprocating air compressor to determine the isothermal and
volumetric Efficiencies at various delivery pressures

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Apparatus required:
* Air compressor with accessories.
* Stop watch.
Description:
Two stage air compressors is a reciprocating type driven by a prime mover. The test rig consist of a base on

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which the tank is mounted. The outlet of the compressor is connected to the receiver. The suction is
connected to air tank with a calibrated orifice plate through a water manometer. The input to the motor is
recorded by an energy meter. The temperature and pressure of the air compressed is indicated by a
thermometer and pressure gauge.
Specifications:

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1. Air compressor:
* LP Bore, DLP = 63.0 mm.
* HP Bore, DHP = 79.0 mm.
* Stroke, L = 80.0 mm.
* Speed, N = 1440 rpm (5 HP)

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* Effective radius = 0.193 m
2. Air receiver capacity = 0.33 m3
3. Orifice, diameter, d0 = 12 mm
4. Orifice area,. A0 : ?d0
2

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/ 4 = ----------- m
2

5. Coefficient of discharge C d. = 0.6
6. Energy-meter constant = 200 rev / kWh

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66 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

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Observation Table: II
Sl.
No.
Actual
Discharge

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Va
Theoritical
Discharge
Vt
Volumetric

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Efficiency
?
Power
Input

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Output
Power

Overall
Efficiency

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?0
Isothermal
Workdone
IwD
Polytropic

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Workdone
PwD
Isothermal
Efficiency
?iso

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m
3
/sec m
3
/sec % kW kW % J/Kg J/Kg %

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Sl.
No.
Pressure

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p
Manometer
h1
Manometer
h2

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Time for 5 revolutions Energy meter Speed of the compressor Temperature
T1
Temperature
T1
Kg/cm

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2
Cm cm sec rpm
o
C
o

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C



67 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Check whether manometer is filled with water up to the required level.
2. The maximum pressure in the receiver tank should not exceed 12 kg / cm
2

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Procedure:
1. Ensure that gauge pressure in the tank is zero.
2. Start the compressor. Read the receiver pressure gauge for a particular pressure.
3. Maintain the pressure constant by adjusting the outlet valve.

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4. Note down the manometer reading and time taken for 3 revolution of the energy
Formulae used:
1. Density of air at RTP:
? RTP = ? NTP X 273 Kg/ m
3

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(273 + Room Temp)
Where density of air at NTP = 1.293 Kg/ m
3
.

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2. Air head causing flow:
ha RTP = (h1 - h2) x ? water m
?a RTP
Where,

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(h1- h2) = Difference in manometer liquid, in m.

3. Actual volume at RTP:
Va RTP = C.d x Ao x ? 2 g ha RTP
Where,

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C d= Coefficient of discharge = 0.6.
A o = Area of orifice = ?(d0)
2
m
2

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.
4
Diameter of orifice d o = 0.01 m.
4. Actual volume at NTP:
Va NTP = VaRTP x T NTP

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T RTP
Where,
T NTP = Normal temp - 273
o
k

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T RTP = Room temp -
o
c (273 + TROOM )

68 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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5. Theoretical Volume of air: (at intake conditions)
V T = ?D
2
x L x Nc m

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3
/ sec.
4 x 60
D = LP Bore diameter = 88.5 mm.
L = Stroke length = 88.9 mm.

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Nc = Compressor speed rpm.
6. Volumetric Efficiency:(for LP stage)
?vol = Va NTP x 100%
Vt
7. Shaft Input through Energy meter:

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= 1 x n x ?t x ?m x 3600 kw.
( Ec x t )
Where,
Ec = Energy meter constant = 200 rev / kWh

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?t = Efficiency for transmission = 0.95.
? m = Efficiency for motor = 0.90.
t = Time for 'n' revolution of energy meter disc.
n = no. of rev. of Energy meter disc.

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8. Isothermal power:
= Pa x Va RTP x log e (R) W
1000
Pa = Atmospheric pressure in N/ m
2

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= 1.01325 x 10
5
N / m
2
.

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R = (Pressure gauge reading + atmospheric pressure)
atmospheric pressure.
9. Isothermal efficiency:
? ISO = Isothermal power x 100%
Shaft input

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Result:
The values of isothermal and volumetric efficiency at various delivery pressures have been studied &
graph between Pressure Vs Volumetric efficiency and Pressure Vs Isothermal efficiency are drawn.

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69 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Outcome:
From this experiment, conducting the load test on two stage reciprocating air compressor for

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determining the isothermal and volumetric Efficiencies at various delivery pressures is understood and this
experiment could be used in the areas such as Refrigerator, Air Conditioning, IC engines, etc.

Applications:
Refrigerator, Air Conditioning, IC engines.

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1. How are air compressors classified?
2. Define ? Isothermal Efficiency of Air Compressor
3. What is meant by FAD (Free Air Delivery)?

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4. What is meant by perfect inter-cooling?
5. Define ? Clearance Ratio of an Air Compressor
6. List out the applications of compressed air.
7. What are the types of air compressors?
8. What is meant by single acting compressor?

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9. What is meant by double acting compressor?
10. What is meant by single stage compressor?
11. What is meant by multi stage compressor?
12. Indicate the applications of reciprocating compressors in industry>
13. Define ? Mechanical Efficiency

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14. What is meant by compression ratio?
15. What are the factors that affect the volumetric efficiency of a reciprocating compressor?

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Viva ? voce

70 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.14

PERFORMANCE TEST IN A HC REFRIGERATION

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SYSTEM


Aim:

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To conduct the performance test on Vapour Compression Refrigeration System and to determine the
Coefficient of Performance using solenoid valve by throttling method

Description:

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In this system the working fluid is a HC out of a refrigeration system. The HC compression system is most
important system from the view point of commercial and domestic utility. The HC refrigerant at low temp and
pressure enters the reciprocating compressor, where it is compressed isentropically and subsequently its temp
and pressure increases considerably. This HC after leaving the compressor enters the condenser where it is
cooled into low temperature. Then it is sucked by reciprocating compressor and is thus repeated.

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Formula used:

Actual COP = refrigerant effect
I/p energy to compressor
Refrigerant effect = mxCpx ? T

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t
m - mass of water (kg)
Cp - Sp. Heat of water (4.2 kJ/kg K)
?T ? decrease in temp (Ti-Ts)
t - timetaken duration of expt (sec)

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Energy input =n x 3600 /k x t
n ? number of revolutions in energy meter
t ? time taken of ?n? revolutions
k ? energy meter constant (3200)

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71 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:

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Pressure of the refrigerant (Mpa) Temperature Time for n?
rev of
energy
meter in

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sec
P1 P2 P3 P4 Circulating fluid
temp
Refrigerant temp

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Ti Tf T1 T2 T3 T4

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FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?



DEPARTMENT OF

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MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

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Name : _______________________________________

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Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION
MISSION

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4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals

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To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them

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3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills

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To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering

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and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME OUTCOMES (POs)

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On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship

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3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical

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environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination

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10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:

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1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall

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6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

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REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor

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14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus

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5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.

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10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at

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various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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CONTENTS


Sl.No.

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Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2

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Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3
Determination of heat transfer coefficient under natural convection from a

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vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27

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CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34

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8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51

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12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72

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ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

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Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:

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(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:

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The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.

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Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts

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on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:
1. Power input, Q = V ? A / 2 W

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2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:

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1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do

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not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm

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3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm

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8. Mean temperature range = 40
0
C ? 100
0
C

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9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)

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12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)

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17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C
19. Width of gap between two heater plates (x) = 2.5 mm

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20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter
V
Ammeter
A

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Main heater (
0
C) Test Plate (
0
C)

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T1 T2 T3 T4 T5 T6



Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.

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2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.

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5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

Outcome:

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From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

Applications:

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Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins

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5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?

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10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?

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15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?

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20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE

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APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:

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(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter

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Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:

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1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the

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experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:

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The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.

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L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.
No.

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Voltage
(V)
Current
(A)
Heater Temperature

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(
0
C)
Asbestos Temperature
(

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0
C)
Saw dust
Temperature (
0

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C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.

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3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by

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thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m

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2
-K

Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe

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apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?

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3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection

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8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?

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13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?

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18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

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Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:

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(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:

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The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is

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measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the

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relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Schematic view of the test set-up:
mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm

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2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300

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0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V

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8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

Tabulation:
Sl. No.

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Voltage Current Temperature of Thermocouple (
0
c)

V A

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T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2

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K
As = Area of heat transfer surface = ? x d x l m
2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7

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0
C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0

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C) ?
2. hL / k = A { g L
3
?T Cp ?/2v
2

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}
n

Where, hL / k are called Nusselt Number.
L

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3
g?T / v
2
is called Grashof number.
?Cp / k called Prandtl Number.

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A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid

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Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)

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0
K
-1

Where Tf = (Ts + Ta )/ 2

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For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25

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for 10
4
< Gr.Pr.<10
8

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hL / k = 0.13 (Gr.Pr)
1/3
for 10
8
< Gr.Pr.<10

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12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).

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5. Repeat the experiment at different heat inputs.

Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m

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2
K
Experimental = ______________ W/ m
2
K

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Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be

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found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)

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2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness

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7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?

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12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.

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17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No. 4

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION

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FROM A TUBE

Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater

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is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

Sl. No. Voltage Current Temperature in (
0
C)

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Manometer
reading of water
in h in meter

(V) (A)

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T1

T2

T3

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T4

T5

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T6

h1
cm
h2

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cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Pipe diameter outside (Do) = 40 mm

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2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C

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7. Temperature Indicator = Range 0 to 300
0
C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V

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9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.

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3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W

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Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.

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3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)

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Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o
C)
= T6 ? T1.

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2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di
2

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?2gH x (?w / ?a) m
3
/hr
3. ha = qa /A(Ts- Ta) W / m
2

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K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

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Ta = Average temperature of air = (T1 + T6)/2
o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o

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C
Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

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?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

d = diameter of orifice meter = 0.014 m

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g = acceleration due to gravity = 9.81 m/s
2

using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:

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Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature

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(T1 + T6)/2
o
C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number

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K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

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k = Thermal conductivity of fluid W/m
2
K
Nu = 0.023 (Re)

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0.8
(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

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Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m
2

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K
htheoritical = -------------- W/m
2
K

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Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.

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5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.

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10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?

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15. Define ? Momentum Thickness

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Viva ? voce

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29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:

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To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different

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materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A

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channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in

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series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm

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4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.

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3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as

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Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3

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Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter

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reading
(V)
Ammeter
reading
(A)

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T1
(
0
C)
T2

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(
0
C)
T3
(

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0
C)
T4
(
0

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C)
T5
(
0
C)

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T6
(
0
C)
T7

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(
0
C)
T8
(

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0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:

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The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

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Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. Define ? Heat Transfer

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2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?

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6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?
10. Define ? Heat Exchanger

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11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

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Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

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The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input

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power and dimmer stat is provided to vary the input power.

Procedure:

1. Switch on the unit and adjust the input power to the required extent.

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2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter
reading( V)

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Ammeter
reading (A)
T1
(
0

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C)
T2
(
0
C)

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T3
(
0
C)
T4

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(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the

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inner sphere, and the outer sphere respectively.


34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Fig. 1 Apparatus of thermal conductivity of insulating powder

[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

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Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

Outcome:

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From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?

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5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?

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10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)

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15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?

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20. What is meant by steady state heat conduction?

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Viva ? voce

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36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

HEAT TRANSFER FROM PIN-FIN APPARATUS

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(NATURAL AND FORCED CONVECTION MODES)

Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:

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(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is

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connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.

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Tabulations:
Forced convection:
Sl.
No.
V I

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Fin Temperatures (
0
C)
Ambient Temp

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(
0
C)
Manometer
Reading

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(V)

(A)

T1 T2 T3 T4 T5 T6 T7 T8

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h1
cm
h2
cm

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Specifications:
1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm

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4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm

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7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.

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0
C
12. Temperature indicator = 0 ? 300
0
C

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(With compensation of ambient temperature up-to 50
0
C)
13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)

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15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8
Brass Pin Fin
Heater

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38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

16. Ammeter = 0 ? 2 A
Precautions:

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1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.

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6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:
Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,

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100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.

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5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)

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2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m
3
/s.

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Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m
3

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?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s
2

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Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

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39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

A = area of the duct
4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number

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Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2
o

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C
5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number
6. Nusselt Number:
Nu = CRe

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m
(Pr)
0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,

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Where, p = perimeter in m
k= 386 w/mk
m= ?(hp/kA)
A = area of fin = (? x D
2

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) /4
L = Length of the fin
Tw ? average temperature
T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL

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Results:
Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

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Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.

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40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Extended Surface
2. What is meant by convective mass transfer?

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3. State the applications of fins.
4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer
6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?

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8. Define ? Conduction
9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?
11. Define ? Convection
12. What is meant by transient heat conduction?

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13. What is meant by radiation?
14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

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41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.8

DETERMINATION OF STEFAN ? BOLTZMANN

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CONSTANT

Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:

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(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Geyser water
Theory:

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The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a

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hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.

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Specifications:
1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm

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5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0

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C
= (or) 0.1 Kcal / kg
0
C
9. No. of thermocouples mounted on B = 4 Nos.

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10. No. of thermocouples mounted on D = 1 No.

42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

11. Temperature indicator digital 0.1

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0
C L.C 0 - 200
0
C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.

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12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.

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Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4
? Td
4

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)
Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

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Schematic view of the test set-up:

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Heater

43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:
Proc
edur
e:
1. H

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eat the
water
in the
tank by
the immersion heater up to a temperature of about 90

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0
C.
2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling

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the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

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Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m
2
k

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4
.

Outcome:

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From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.
.Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

Sl. No.
Hemisphere Temperature(
0

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C) Avg. Temp.
of the
Hemisphere
(Th)
T4

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Steady
Temp. of
Disc
T0 (Td)
Time

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(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?

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3. State Planck?s distribution law.
4. Define ? Biot Number
5. State Wien?s displacement law.
6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.

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8. What are the various types of convection?
9. Define ? Condensation
10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?

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13. State Krichoff's law or radiation
14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

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45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.9

DETERMINATION OF EMISSIVITY OF A GREY

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SURFACE

Aim:
To measure emissivity of the test plate surface at various temperature
Apparatus required:

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(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with

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heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be

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determined.
Specifications:
1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)

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4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V

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8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300
0
C.

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.

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4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.
Tabulation:
Sl.

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No
Voltage

Current

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Black body
temp(
0
C)
Avg.

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temp.

Polished body
temp (
0

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C)
Avg.
temp.

Enclosure

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Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts
4
? Ta

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4
) A
Eb ? E = (W1 ? W2) / ? (Ts
4
? Ta

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4
) A
E = Eb ? {(W1 ? W2) / ? (Ts
4
? Ta

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4
) A}
Where,
W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W

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A = area of plates = 2 (?/4) xd
2
m
2

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T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)
Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

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47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

? = Stefan boltzman constant = 5.67 x 10
-8

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W/m
2
K
4

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Schematic view of the test set-up:


Procedure:

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1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by
the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state

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condition.

Results:
The emissivity of the test plate surface is found to be _____________.
Outcome:

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From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Emissivity
2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?
4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?

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6. What is meant by shape factor?
7. Define ? Radiation
8. What is meant by monochromatic emissive power?
9. Define ? Emissive Power
10. What is meant by absorptivity?

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11. Define ? Black Body
12. What is meant by transmissivity?
13. State Plank's distribution law
14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.10

EFFECTIVENESS OF PARALLEL / COUNTER
FLOW HEAT EXCHANGE

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Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:
(i) Experimental Setup
(ii) Stop watch

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(iii) Thermometer
Theory:
Heat exchangers are classified in three categories:
1. Transfer type
2. Storage type

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3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.
The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.

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ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water
which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by

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means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:
1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm

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3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50
0
C - 2 Nos.

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6. Thermometers (for hot water) = 0 ? 100
0
C - 2 Nos.
7. Measuring flask = 0 ? 1000 CC

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50 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

8. Geyser: single phase type to obtain hot water supply
9. Thermo Cole insulation for outer pipe.
Precautions:

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Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Tabulations:
Sl.
No.

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Flow Hot Fluid (
0
C) Cold Fluid (
0
C)

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Time for
collection of
hot fluid
Kg/sec
Time for

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collection
of cold fluid
Kg/sec
1 Parallel flow
Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)
1. Area of the pipe A = ? (D ? d) L
Where, D = inlet diameter of the outer tube

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d = outlet diameter of the inner tube
L = Length of the tube

2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

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51 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Where, m = mass flow rate Kg/ sec.
m = ?v/t, ? = density of water and t = time taken for hot water
Cp = Specific heat of capacity 4.187 kJ/kg -K

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Thi = Temperature of hot water inlet
Tho = Temperature of hot water outlet

3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W
Where, m = mass flow rate

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Cp = Specific heat of capacity
Tco = Temperature of cold water inlet
Tci = Temperature of cold water outlet
4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W
Where, Q? = (Qa + Qc) / 2

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5. Logarithmic mean temperature difference( L M T D)
?Tm = (?Ti - ?To) / In (?Ti/?To)
Where, ?To = Tho ? Tco
?Ti = Thi ? Tci
6. Over all heat transfer coefficient

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h = Q?/?Tm A W/m
2
K
where Q? = (Qa + Qc) / 2

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Procedure:
1. Place the thermometers in position and note down their readings when they are at room temperature and
no water is flowing at either side. This is required to correct the temperature.
2. Start the flow on hot water side.
3. Start the flow through annulus and run the exchanger as parallel flow unit.

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4. Put ON the geyser.
5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.
6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.
7. Keeping the flow rates same, wait till the steady state conditions are reached.
8. Record the temperatures on hot water and cold water side and also the flow rates accurately.

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9. Repeat the experiment with a counter flow under identical flow conditions.
10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Result:
1. The values of effectiveness of heat exchanger were found as
(i) Parallel flow = ________.
(ii) Counter flow = _________.

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2. Over all heat exchanger (heat transfer coefficient)
(i) Parallel flow = ________.
(ii) Counter flow = _________.

Outcome:

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From this experiment, determining the values of effectiveness of parallel and counter flow
heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat
exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Heat Exchanger
2. What are the types of heat exchangers?

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3. What is meant by indirect contact heat exchanger?
4. Write about the merits of drop wise condensation.
5. What is meant by film wise and drop wise condensation?
6. What is meant by effectiveness?
7. Define ? Direct Heat Exchanger

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8. What is meant by fouling factor?
9. Distinguish between regenerator and recuperates.
10. What is meant by parallel flow heat exchanger?
11. What is meant by counter flow heat exchanger?
12. What is meant by cross flow heat exchanger?

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13. What is meant by shell and tube heat exchanger?
Viva ? voce

53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.11

DETERMINATION OF COP OF A REFRIGERATION
SYSTEM

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Aim:
To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration
system
Apparatus required:
(i) Thermometer

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(ii) Electric Heater
(iii) Stop watch
(iv) Experimental setup
Description:
1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a

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reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.
2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated
wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a
low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the
temperature of chilled water. The above unit is located on the trolley behind front panel.

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3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic
expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum
strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure
gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high
pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy

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meter to measure the power consumed either by hater or by compressor.

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54 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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A. A compressor condenser unit placed inside trolley and fitted with
1. R-134a reciprocating compressor
2. Condenser
3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan
4. A receiver with angle check valve

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B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity
placed inside a well insulated wooden box and provided with
5. Evaporator coil
6. Stirrer
7. Electric heater 230 V, A.C.

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8. The sensing bulb of low temperature thermostat.
9. A high temperature thermostat.
10. A Thermometer to measure the chilled water temperature
C. The front panel on which are mounted the following
11. Capillary expansion tube with isolating valve.

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12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator
and isolating valve
13. Drier cum strainer and sight glass
14. Thermostat at inlet and outlet of both evaporator and condenser
15. Pressure gauge at inlet and outlet of evaporator and condenser

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16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out
17. Heat power regulator switch and regulator
18. Energy meter to measure the power consumed either by hater or by compressor.

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Precautions:
1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.

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2. The heater regulator should be switched off whenever not in use. Heating water beyond 40
0
C may lead to
permanent damage of the entire system. A high temperature cut off thermostat is provided in the water
chiller, to cut off the heater beyond 30

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0
C.Check the setting of the same before operation.
3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.
4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.
5. The solenoid thermostat is adjusted to cut at 15

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0
C and cut in at 10
0
C of the chilled water. Do not alter the
same.

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6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.
7. The space near the condenser should permit good ventilation to aid proper fan performance.
8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked
in
0

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F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,
calibrated in SI units, are not available.)
9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to
obtain the pressure in MN/m
2

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.e.g. P = x psig
= (x + 14.7) psia
= (x + 14.7) / 145 MN/m
2
(MPa)

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10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.
Formulae used:
Let, State 1 indicates the entry of compressor.
State 2 indicates the exit of compressor.
State 3 indicates the exit from condenser.

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State 4 indicates the entry to evaporator
P = Pressure (bar)
T = Temperature (
0
C)

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H = Specific enthalpy (kJ/kg)
v = Specific Volume (m
3
/Kg)
n = Number of revolutions of energy meter disc.

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t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)
t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)
K = Energy meter constant = 3200 lmp / kWh
N = Speed of compressor = 2840 rpm
h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

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h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2
h3 = Specific enthalpy at Pc and T3 (kJ/kg)

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h4 = h3
Stroke volume of compressor = (?/ 4) d
2
l = 12.58 x 10
-6

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m
3

1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar
2. Average condenser pressure, Pc = (P2 + P3) / 2 bar

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3. Heater input, Qe = (n / t1) x (3600 / k) kW
4. Compressor input, W = (n / t2) x (3600 / k) kW
5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1
6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)
7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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57 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

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Sl.
No.

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Initial
Temp.
of water

Final

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Temp.
of water
Duration
of exp.

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Delivery
pressure

Delivery
Temp.

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Condense
Outlet
Pressure

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Condense
Outlet
Temp.

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Pressure
after
throttling

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Temp.
After

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Throttli
ng


Suction

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pressur
e
Suction
Temp.

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Time for
10 rev. of

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compress
or energy
meter

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Height
of water
in the
vessel

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58 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
Load Test with Capillary tube as expansion device:
1. Fill the chilled water calorimeter with pure water so that the evaporative coils are

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fully immersed.
2. Select the capillary tube line by opening the shut-off valve on this line and closing
the one on the thermostatic expansion valve line. The solenoid switch is switched OFF.
3. Start the compressor and run for some time so that the chilled water temperature
is lowered to the given test temperature.

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4. Switch on the heater and slowly increase the power.
5. Allow The temperature in water calorimeter to reach the equilibrium
temperature.
6. Connect energy meter to motor and heater by the selector switch one after another
and note down the time taken for 10 pulses of the energy meter disc.

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7. Note down the pressure and temperature readings at locations 1,2,3 & 4 as
mentioned.
8. Switch OFF the heater and the mains.
Result:
The load test on a refrigeration test rig was conducted and the results are as follows.

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1. Actual C.O.P. of the system =____________.
2. Rhetorical C.O.P. of the system = ___________.
3. Volumetric Efficiency = ___________.

Outcome:

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From this experiment, conducting the load test on a refrigeration test rig and finding out the
volumetric efficiency and co-efficient of performance for any type of refrigerant is learnt and this experiment
could be used in the areas such as Refrigerator and Air Conditioning.
Applications:
Refrigerator, Air Conditioning.

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59 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? COP
2. Which thermodynamic cycle is used in air conditioning of airplanes using air as refrigerant?

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3. Define ? Ton of Refrigeration
4. What is meant by refrigeration?
5. What is meant by air conditioning?
6. What are the four important properties of a good refrigerant?
7. How does the actual vapour compression cycle differ from that of the ideal cycle?

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8. Name any four commonly used refrigerants.
9. What are the expansion devices used in a vapour compression plant?
10. Why throttle valve is used in place of expansion cylinder for vapour compression refrigerant machine?
11. What are the merits of air refrigeration system?
12. What are the demerits of air refrigeration system?

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13. Define ? Refrigerant
14. What is net refrigerating effect of the refrigerant?
15. What are the methods to obtain sub cooling of refrigerant?

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Viva ? voce

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60 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.12 EXPERIMENTS ON PSYCHROMETRIC PROCESS

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Aim:
To conduct an experiment on psychrometric processes with air conditioning system
Apparatus required:
(i) Thermometer
(ii) Electric Heater

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(iii) Stop watch
(iv) Digital anemometer
(v) Experimental setup
Description:
The test rig consist of

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1. An air duct support of stand
2. A blower to set up air flow through the duct along with a speed control to vary the
velocity of air.
3. A heater to rise the air temperature with regulator and energy meter.
4. Water spray, collecting tray, reservoir with gauge pump.

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5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.
(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after cooling coil).
6. The test rig consist of compressor, condenser unit placed inside trolley and fitted
with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for
condenser and (iv) Liquid receiver.

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7. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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61 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Observation Table: I

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Precautions:
1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence
avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kw only for the motor
circuit.

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2. Natural air currents in the room if in the direction of air duct may defect the experimental results and
hence the duct should be placed such that no wind from doors, windows, fan and cooling air from
other test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan
and should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase
beyond 240 psi.

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3. Never exceed dry bulb temperatures of 40
0
C after the heater (station 2) otherwise the air duct may be
damaged.
4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may

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exceed its maximum of 32
0
C and calibration may be affected.
5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not
running this will lead to rise in temperature at the heater and may damage the heater and the air duct.

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6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their
duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.
7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer
is placed inside the reservoir at the top. This may have to the cleaned when necessary.
8. Do not open the gate valve fully otherwise water may be splashed outside and the waster

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measurement may be in error.
S.
N
o
Inlet temp

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Outlet
temp
Pressu
re
P1

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Tem
p.
T1
Pressu
re

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P2
Temp.
T2
Pressu
re

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P3

Tem
p.
T3

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Pressu
re
P4

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Temp.
T4
Energy

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for 10
revolutio
ns
Twet Tdry Twet Tdry Lb/in
o

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C Lb/in
o
C Lb/in
o
C Lb/in

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o
C


62 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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9. If the low pressure cut out comes in to action, it means that the Freon charge is insufficient and may
have to be filled up. The suction pressure should never go below 2 psi as otherwise the compressor
seals will be damaged and air and moisture may enter the system.
10. The refrigerant strainer placed on the front panel should always be warm. If it cools and moisture

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condenser on it, then the strainer might have to be charged by an experienced refrigeration
mechanics.
11. The refrigerating system can work continuously for 2 hours, however if the room temperature is above
25
0

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C the condenser may be heated up and the delivery pressure may rise. Do not exceed 240 psi.
Pour one or two glasses of drinking water over the fins of the condenser in order to reduce the
delivery pressure.
12. After some months of operation the compressor may have to be topped up with oil and some quantity
of Freon-22 may have to be charged by an experienced mechanics.

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13. See that distilled water is filled up in the plastic dishes provided under the wet bulb thermometers and
that the wicks are in tact otherwise erroneous readings may be obtained. These thermometers will
show correct readings only when the fan is in operation.
14. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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Formulae used:
1. Corresponding to the dry and wet bulb temperature at all the stations obtain the specific enthalpy and
specific humidity values from psychrometric chart.
i.e., h1 and w1 at tb1 and tw1 and so on.

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2. Air flow rate, ma = (A x V) / v4 Kg / sec
Where, A = Area of duct at outlet in m
2
(0.46 m x 0.086 m)
V = Air velocity ( m / sec)

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V4 = Specific volume of moist air at station 4 using psychometric chart m
3
/Kg
3. Moisture added from psychrometric chart, mw1 = ma (w3-w2) Kg / sec.
Where, w3 = Specific humidity at station 3

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w2 = Specific humidity at station 2
4. Cooling effect produced on air, Qe = ma (h3 ? h4) kW.
Where, h3 = Specific enthalpy at state 3 kJ/kg
h4 = Specific enthalpy at state 4 kJ/kg
5. Moisture condensed, mcl = ma (w3 ? w4) kg/sec

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Where, w3 = Specific humidity at station 3
w4 = Specific humidity at station 4

63 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Fill water in the wet bulb temperature probe trays.
2. Start the main.
3. Start the blower and run it the required speed by keeping the speed regulator at
position.

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4. Start the spray pump and open the gate valve suitably.
5. Start the heater.
6. Select the expansion device (Capillary tube / Thermostatic expansion valve)
7. Start the cooling compressor.
8. Wait for some time till thermometers shown practically constant readings and note down the

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following readings:
(i) Dry bulb temperatures tdb1, tdb2, tdb3, tdb4.
(ii) Wet bulb temperatures twb1, twb2, twb3, twb4.
(iii) Spray water temperature, ts
(iv) Surface temperature of cooler, tm ( at control panel)

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(v) Pressure gauge reading, pd ( at control panel)
(vi) Compound gauge reading, Ps ( at control panel)
(vii) Level reduction?l? in spray reservoir (mm) during 5 min.
(viii) Amount of condensate collected ?lc?, in a measuring jar at cooler tray during a
run of 5 minutes at constant conditions.

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(ix) Time in second ?SH? for 10 pulses of the energy meter disc connected to the
heater.
(x) Time in seconds Sc for 10 pulses of the energy meter disc connected to cooler
compressor.
Result:

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Experiment on psychrometric processes with air conditioning system was drawn
Outcome:
From this experiment, conducting the test on psychrometric processes with air
conditioning system is learnt and this experiment could be used in all types of air conditioning systems.

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Applications:
Air Conditioning.

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64 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is the commonly used unit of refrigeration?

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2. Distinguish between summer air conditioning and winter air conditioning.
3. Define ? RSHF Line
4. Define ? By Pass Factor of a Heating Coil
5. What is the effect of sub cooling a refrigerant in a vapour compression cycle?
6. What is the function of analyzer and rectifier in an absorption system?

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7. What is the purpose of generator assembly in vapour absorption refrigeration system?
8. State the substance used in the Lithium Bromide system and their functions.
9. Differentiate wet compression from dry compression.
10. Define ? Apparatus Dew Point
11. What is meant by dew point temperature?

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12. Define ? Wet Bulb Temperature
13. Define ? Degree of Saturation
14. What is meant by specific humidity?
15. Define ? Relative Humidity

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Viva ? voce

65 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.13

PERFORMANCE TEST ON A RECIPROCATING
AIR COMPRESSOR

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Aim:
To conduct a load test on the 2 - stage reciprocating air compressor to determine the isothermal and
volumetric Efficiencies at various delivery pressures

Apparatus required:

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* Air compressor with accessories.
* Stop watch.
Description:
Two stage air compressors is a reciprocating type driven by a prime mover. The test rig consist of a base on
which the tank is mounted. The outlet of the compressor is connected to the receiver. The suction is

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connected to air tank with a calibrated orifice plate through a water manometer. The input to the motor is
recorded by an energy meter. The temperature and pressure of the air compressed is indicated by a
thermometer and pressure gauge.
Specifications:
1. Air compressor:

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* LP Bore, DLP = 63.0 mm.
* HP Bore, DHP = 79.0 mm.
* Stroke, L = 80.0 mm.
* Speed, N = 1440 rpm (5 HP)
* Effective radius = 0.193 m

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2. Air receiver capacity = 0.33 m3
3. Orifice, diameter, d0 = 12 mm
4. Orifice area,. A0 : ?d0
2
/ 4 = ----------- m

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2

5. Coefficient of discharge C d. = 0.6
6. Energy-meter constant = 200 rev / kWh

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66 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

Observation Table: II

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Sl.
No.
Actual
Discharge
Va

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Theoritical
Discharge
Vt
Volumetric
Efficiency

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?
Power
Input

Output

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Power

Overall
Efficiency
?0

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Isothermal
Workdone
IwD
Polytropic
Workdone

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PwD
Isothermal
Efficiency
?iso
m

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3
/sec m
3
/sec % kW kW % J/Kg J/Kg %

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Sl.
No.
Pressure
p

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Manometer
h1
Manometer
h2
Time for 5 revolutions Energy meter Speed of the compressor Temperature

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T1
Temperature
T1
Kg/cm
2

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Cm cm sec rpm
o
C
o
C

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67 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Check whether manometer is filled with water up to the required level.
2. The maximum pressure in the receiver tank should not exceed 12 kg / cm
2

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Procedure:
1. Ensure that gauge pressure in the tank is zero.
2. Start the compressor. Read the receiver pressure gauge for a particular pressure.
3. Maintain the pressure constant by adjusting the outlet valve.
4. Note down the manometer reading and time taken for 3 revolution of the energy

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Formulae used:
1. Density of air at RTP:
? RTP = ? NTP X 273 Kg/ m
3

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(273 + Room Temp)
Where density of air at NTP = 1.293 Kg/ m
3
.

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2. Air head causing flow:
ha RTP = (h1 - h2) x ? water m
?a RTP
Where,
(h1- h2) = Difference in manometer liquid, in m.

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3. Actual volume at RTP:
Va RTP = C.d x Ao x ? 2 g ha RTP
Where,
C d= Coefficient of discharge = 0.6.

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A o = Area of orifice = ?(d0)
2
m
2
.

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4
Diameter of orifice d o = 0.01 m.
4. Actual volume at NTP:
Va NTP = VaRTP x T NTP
T RTP

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Where,
T NTP = Normal temp - 273
o
k
T RTP = Room temp -

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o
c (273 + TROOM )

68 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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5. Theoretical Volume of air: (at intake conditions)
V T = ?D
2
x L x Nc m
3

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/ sec.
4 x 60
D = LP Bore diameter = 88.5 mm.
L = Stroke length = 88.9 mm.
Nc = Compressor speed rpm.

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6. Volumetric Efficiency:(for LP stage)
?vol = Va NTP x 100%
Vt
7. Shaft Input through Energy meter:

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= 1 x n x ?t x ?m x 3600 kw.
( Ec x t )
Where,
Ec = Energy meter constant = 200 rev / kWh
?t = Efficiency for transmission = 0.95.

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? m = Efficiency for motor = 0.90.
t = Time for 'n' revolution of energy meter disc.
n = no. of rev. of Energy meter disc.

8. Isothermal power:

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= Pa x Va RTP x log e (R) W
1000
Pa = Atmospheric pressure in N/ m
2
= 1.01325 x 10

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5
N / m
2
.
R = (Pressure gauge reading + atmospheric pressure)

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atmospheric pressure.
9. Isothermal efficiency:
? ISO = Isothermal power x 100%
Shaft input

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Result:
The values of isothermal and volumetric efficiency at various delivery pressures have been studied &
graph between Pressure Vs Volumetric efficiency and Pressure Vs Isothermal efficiency are drawn.

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69 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Outcome:
From this experiment, conducting the load test on two stage reciprocating air compressor for
determining the isothermal and volumetric Efficiencies at various delivery pressures is understood and this

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experiment could be used in the areas such as Refrigerator, Air Conditioning, IC engines, etc.

Applications:
Refrigerator, Air Conditioning, IC engines.

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1. How are air compressors classified?
2. Define ? Isothermal Efficiency of Air Compressor
3. What is meant by FAD (Free Air Delivery)?
4. What is meant by perfect inter-cooling?

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5. Define ? Clearance Ratio of an Air Compressor
6. List out the applications of compressed air.
7. What are the types of air compressors?
8. What is meant by single acting compressor?
9. What is meant by double acting compressor?

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10. What is meant by single stage compressor?
11. What is meant by multi stage compressor?
12. Indicate the applications of reciprocating compressors in industry>
13. Define ? Mechanical Efficiency
14. What is meant by compression ratio?

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15. What are the factors that affect the volumetric efficiency of a reciprocating compressor?

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Viva ? voce

70 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.14

PERFORMANCE TEST IN A HC REFRIGERATION
SYSTEM

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Aim:

To conduct the performance test on Vapour Compression Refrigeration System and to determine the

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Coefficient of Performance using solenoid valve by throttling method

Description:

In this system the working fluid is a HC out of a refrigeration system. The HC compression system is most

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important system from the view point of commercial and domestic utility. The HC refrigerant at low temp and
pressure enters the reciprocating compressor, where it is compressed isentropically and subsequently its temp
and pressure increases considerably. This HC after leaving the compressor enters the condenser where it is
cooled into low temperature. Then it is sucked by reciprocating compressor and is thus repeated.
Formula used:

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Actual COP = refrigerant effect
I/p energy to compressor
Refrigerant effect = mxCpx ? T
t

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m - mass of water (kg)
Cp - Sp. Heat of water (4.2 kJ/kg K)
?T ? decrease in temp (Ti-Ts)
t - timetaken duration of expt (sec)

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Energy input =n x 3600 /k x t
n ? number of revolutions in energy meter
t ? time taken of ?n? revolutions
k ? energy meter constant (3200)

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71 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:

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Pressure of the refrigerant (Mpa) Temperature Time for n?
rev of
energy
meter in
sec

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P1 P2 P3 P4 Circulating fluid
temp
Refrigerant temp

Ti Tf T1 T2 T3 T4

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72 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Model calculation:

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Actual COP = refrigerant effect
I/p energy to compressor

Refrigerant effect = mxCpx ? T
t

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m - mass of water (kg)
Cp - Sp. Heat of water (4.2 kJ/kg K)
?T ? decrease in temp (Ti-Ts)
t - time taken duration of experiment (sec)
Refrigerating effect = 8x4.2x (27-6)/1200=0.588 kw

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Energy input = n x 3600
n ? Number of revolutions in energy meter
t ? Time taken of ?n? revolutions
k ? Energy meter constant

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=3 x 3600/(1200 x 54)
=0.166 kW
Actual COP = refrigerant effect
I/p energy to compressor
= 0.588/0.166

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=3.526
Result:

The experiment was conducted successfully and coefficient of performance was found out is _______.

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Outcome:
From this experiment, conducting the performance test on Vapour Compression Refrigeration
System and to determine the Coefficient of Performance using solenoid valve by throttling method is
understood and this experiment could be used in the areas such as Refrigerator and Air Conditioning systems.
Applications:

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Refrigerator, Air Conditioning.

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FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________

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Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and

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enterprising professionals conforming to global standards through value based quality education and training.



? To provide competent technical manpower capable of meeting requirements of the industry

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? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING



Rendering the services to the global needs of engineering industries by educating students to become

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professionally sound mechanical engineers of excellent caliber



To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on

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experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould

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them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth

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To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up

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their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME OUTCOMES (POs)

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On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications

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4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability

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8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills

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11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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ME6512 ? THERMAL ENGINEERING LABORATORY ? II



? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the

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performance of refrigeration cycle / components

LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus

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2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder

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7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

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REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System

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15. Performance test in a fluidized Bed Cooling Tower



1. Able to find out the thermal conductivity of various materials.

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2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials

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6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.

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11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures

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14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
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CONTENTS


Sl.No.
Name of the experiment

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Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe

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apparatus
11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder

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15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS

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6
Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39

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9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58

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13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS

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16 Air conditioning test rig 75
PROJECT WORK 81

8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

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Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup

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(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to

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prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater

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assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved

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aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK

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3. Area, A = ( ?/4) d
2
(10 + x)

cm

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2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.

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2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there

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is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

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Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm

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4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40

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0
C ? 100
0
C
9. Maximum temperature of the hot plate = 170

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0
C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)

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13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)

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18. Temperature indicator = 0 ? 200
0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm

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21. Specimen used = Press wood

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Tabulation:

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Sl. No. Voltmeter
V
Ammeter
A
Main heater (

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0
C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water

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is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from

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thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably

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steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:

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Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded

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hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.

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6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer

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11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?

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16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

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Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup

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(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter
Theory:

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The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in

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the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:
1. Diameter of the heater Rod = 20 mm.

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2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).

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2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by

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Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging

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material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.
No.
Voltage

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(V)
Current
(A)
Heater Temperature
(

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0
C)
Asbestos Temperature
(
0

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C)
Saw dust
Temperature (
0
C)

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T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.

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4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.

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7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2

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-K

Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC

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engines, heat exchangers, etc. where heat transfer is to be found.

Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?

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4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?

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9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?

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14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis

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19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

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Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:
(i) Experimental setup

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(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at

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the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

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When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Schematic view of the test set-up:
mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm

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3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0

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C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V

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9. Heater = Cartridge type (400 W)

Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (

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0
c)

V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:

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1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2
K

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As = Area of heat transfer surface = ? x d x l m
2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0

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C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0
C) ?

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2. hL / k = A { g L
3
?T Cp ?/2v
2
}

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n

Where, hL / k are called Nusselt Number.
L
3

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g?T / v
2
is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.

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Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid

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? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0

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K
-1

Where Tf = (Ts + Ta )/ 2

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For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25
for 10

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4
< Gr.Pr.<10
8

hL / k = 0.13 (Gr.Pr)

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1/3
for 10
8
< Gr.Pr.<10
12

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Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

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Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2

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K
Experimental = ______________ W/ m
2
K

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Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?

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3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?

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8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer

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13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.

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18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No. 4

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

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Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:

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(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

Theory:

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Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat

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supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



Tabulations:

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Sl. No. Voltage Current Temperature in (
0
C)
Manometer

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reading of water
in h in meter

(V) (A)
T1

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T2

T3

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T4

T5

T6

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h1
cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm

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3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300

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0
C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A

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10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.

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4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:

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1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady

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state is reached.
4. Note down the heater input.

26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)

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?T = Temperature rise in air (
o
C)
= T6 ? T1.
2. m = Q?

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Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m

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3
/hr
3. ha = qa /A(Ts- Ta) W / m
2
K

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qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

Ta = Average temperature of air = (T1 + T6)/2

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o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C

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Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

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?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s

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2

using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number

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Where, V = velocity of air = Q/[(? x Di
2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2

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o
C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K

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Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

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k = Thermal conductivity of fluid W/m
2
K
Nu = 0.023 (Re)
0.8

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(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

Results:

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Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m
2
K

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htheoritical = -------------- W/m
2
K

Outcome:

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From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.

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6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?

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11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall

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Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The

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temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus

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uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.

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Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.

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Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.

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4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from

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the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate

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Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter
reading

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(V)
Ammeter
reading
(A)
T1

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(
0
C)
T2
(

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0
C)
T3
(
0

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C)
T4
(
0
C)

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T5
(
0
C)
T6

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(
0
C)
T7
(

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0
C)
T8
(
0

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C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:
The rate of heat transfer through different materials are found to be

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a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

Outcome:

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From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.



32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?

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3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.

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7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?

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12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

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Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between

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the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

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Procedure:

1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.

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3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter
reading( V)
Ammeter

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reading (A)
T1
(
0
C)

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T2
(
0
C)
T3

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(
0
C)
T4
(

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0
C)

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Calculations:

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The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Fig. 1 Apparatus of thermal conductivity of insulating powder

[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

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Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

Outcome:

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From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?

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6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?

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11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection

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16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.7

HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

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Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer
Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of

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the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:

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Forced convection:
Sl.
No.
V I

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Fin Temperatures (
0
C)
Ambient Temp
(

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0
C)
Manometer
Reading
(V)

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(A)

T1 T2 T3 T4 T5 T6 T7 T8
h1

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cm
h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm

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5. Diameter of the delivery pipe (O.D) = 46 mm

Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64

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8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0

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C
12. Temperature indicator = 0 ? 300
0
C
(With compensation of ambient temperature up-to 50

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0
C)
13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V

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T7 T6 T5 T4 T3 T2 T1
T8
Brass Pin Fin
Heater

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38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.

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7. Do not exceed 200 W.
Procedure:
Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.

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2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.

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Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D

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2
) /4}?2gha m
3
/s.
Where, ha (head of air) = (?w / ?a) x H m

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H = Difference of water level in manometer m
?w Density of water = 1000 kg/m
3

?a = Density of air = 1.165 kg/m

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3
g = acceleration due to gravity = 9.81 m/s
2

Cd = Coefficient of discharge = 0.64

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D = diameter of the orifice
3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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A = area of the duct
4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?

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D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2
o
C

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5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number
6. Nusselt Number:
Nu = CRe
m

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(Pr)
0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m

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k= 386 w/mk
m= ?(hp/kA)
A = area of fin = (? x D
2
) /4

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L = Length of the fin
Tw ? average temperature
T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:

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Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

Outcome:

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From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.

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40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.

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4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer
6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction

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9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?
11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?

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14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.8

DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

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Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer

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(ii) Electric Heater
(iii) Stop watch
(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The

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outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A

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chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:

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1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve

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6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C

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= (or) 0.1 Kcal / kg
0
C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

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42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

11. Temperature indicator digital 0.1
0

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C L.C 0 - 200
0
C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW

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13. Tank for hot water
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:

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Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4
? Td
4
)

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Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

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Schematic view of the test set-up:

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Heater

43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulations:

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Proc
edur
e:
1. H
eat the

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water
in the
tank by
the immersion heater up to a temperature of about 90
0

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C.
2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant

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cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

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Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m
2
k
4

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.

Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus

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is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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Sl. No.
Hemisphere Temperature(
0
C) Avg. Temp.

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of the
Hemisphere
(Th)
T4
Steady

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Temp. of
Disc
T0 (Td)
Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?
3. State Planck?s distribution law.

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4. Define ? Biot Number
5. State Wien?s displacement law.
6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.
8. What are the various types of convection?

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9. Define ? Condensation
10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?
13. State Krichoff's law or radiation

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14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.9

DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

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Aim:
To measure emissivity of the test plate surface at various temperature
Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer
Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide

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undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.

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Specifications:
1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.

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Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.

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9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300
0
C.

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.

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5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.
Tabulation:
Sl.
No

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Voltage

Current

Black body

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temp(
0
C)
Avg.
temp.

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Polished body
temp (
0
C)

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Avg.
temp.

Enclosure
Temp.

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(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:

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Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts
4
? Ta
4

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) A
Eb ? E = (W1 ? W2) / ? (Ts
4
? Ta
4

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) A
E = Eb ? {(W1 ? W2) / ? (Ts
4
? Ta
4

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) A}
Where,
W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd

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2
m
2

T = Temperature of black plate, k = (Ts + Ta) / 2

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Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)
Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

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47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

? = Stefan boltzman constant = 5.67 x 10
-8
W/m

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2
K
4

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Schematic view of the test set-up:


Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.

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And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by
the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

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Results:
The emissivity of the test plate surface is found to be _____________.
Outcome:
From this experiment, finding the emissivity of the test plate surface at various

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temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Emissivity

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2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?
4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?
6. What is meant by shape factor?

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7. Define ? Radiation
8. What is meant by monochromatic emissive power?
9. Define ? Emissive Power
10. What is meant by absorptivity?
11. Define ? Black Body

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12. What is meant by transmissivity?
13. State Plank's distribution law
14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.10

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EFFECTIVENESS OF PARALLEL / COUNTER
FLOW HEAT EXCHANGE

Aim:

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To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:
(i) Experimental Setup
(ii) Stop watch
(iii) Thermometer

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Theory:
Heat exchangers are classified in three categories:
1. Transfer type
2. Storage type
3. Direct contact type.

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A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.
The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.

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iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water
which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run

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as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:
1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm

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4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50
0
C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100

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0
C - 2 Nos.
7. Measuring flask = 0 ? 1000 CC

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8. Geyser: single phase type to obtain hot water supply
9. Thermo Cole insulation for outer pipe.
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically

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there is no temperature rise in the circuiting fluid.
Tabulations:
Sl.
No.
Flow Hot Fluid (

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0
C) Cold Fluid (
0
C)
Time for

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collection of
hot fluid
Kg/sec
Time for
collection

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of cold fluid
Kg/sec
1 Parallel flow
Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)
1. Area of the pipe A = ? (D ? d) L
Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube

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L = Length of the tube

2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

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Where, m = mass flow rate Kg/ sec.
m = ?v/t, ? = density of water and t = time taken for hot water
Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet

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Tho = Temperature of hot water outlet

3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W
Where, m = mass flow rate
Cp = Specific heat of capacity

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Tco = Temperature of cold water inlet
Tci = Temperature of cold water outlet
4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W
Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)

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?Tm = (?Ti - ?To) / In (?Ti/?To)
Where, ?To = Tho ? Tco
?Ti = Thi ? Tci
6. Over all heat transfer coefficient
h = Q?/?Tm A W/m

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2
K
where Q? = (Qa + Qc) / 2

Procedure:

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1. Place the thermometers in position and note down their readings when they are at room temperature and
no water is flowing at either side. This is required to correct the temperature.
2. Start the flow on hot water side.
3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.

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5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.
6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.
7. Keeping the flow rates same, wait till the steady state conditions are reached.
8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.

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10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Result:
1. The values of effectiveness of heat exchanger were found as
(i) Parallel flow = ________.
(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)

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(i) Parallel flow = ________.
(ii) Counter flow = _________.

Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow

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heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat
exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Heat Exchanger
2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?

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4. Write about the merits of drop wise condensation.
5. What is meant by film wise and drop wise condensation?
6. What is meant by effectiveness?
7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?

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9. Distinguish between regenerator and recuperates.
10. What is meant by parallel flow heat exchanger?
11. What is meant by counter flow heat exchanger?
12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?

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Viva ? voce

53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.11

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DETERMINATION OF COP OF A REFRIGERATION
SYSTEM

Aim:

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To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration
system
Apparatus required:
(i) Thermometer
(ii) Electric Heater

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(iii) Stop watch
(iv) Experimental setup
Description:
1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a
reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.

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2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated
wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a
low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the
temperature of chilled water. The above unit is located on the trolley behind front panel.
3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic

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expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum
strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure
gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high
pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy
meter to measure the power consumed either by hater or by compressor.

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54 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
A. A compressor condenser unit placed inside trolley and fitted with

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1. R-134a reciprocating compressor
2. Condenser
3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan
4. A receiver with angle check valve
B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity

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placed inside a well insulated wooden box and provided with
5. Evaporator coil
6. Stirrer
7. Electric heater 230 V, A.C.
8. The sensing bulb of low temperature thermostat.

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9. A high temperature thermostat.
10. A Thermometer to measure the chilled water temperature
C. The front panel on which are mounted the following
11. Capillary expansion tube with isolating valve.
12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator

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and isolating valve
13. Drier cum strainer and sight glass
14. Thermostat at inlet and outlet of both evaporator and condenser
15. Pressure gauge at inlet and outlet of evaporator and condenser
16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out

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17. Heat power regulator switch and regulator
18. Energy meter to measure the power consumed either by hater or by compressor.

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55 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.
2. The heater regulator should be switched off whenever not in use. Heating water beyond 40

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0
C may lead to
permanent damage of the entire system. A high temperature cut off thermostat is provided in the water
chiller, to cut off the heater beyond 30
0

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C.Check the setting of the same before operation.
3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.
4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.
5. The solenoid thermostat is adjusted to cut at 15
0

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C and cut in at 10
0
C of the chilled water. Do not alter the
same.
6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.

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7. The space near the condenser should permit good ventilation to aid proper fan performance.
8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked
in
0
F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,

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calibrated in SI units, are not available.)
9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to
obtain the pressure in MN/m
2
.e.g. P = x psig

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= (x + 14.7) psia
= (x + 14.7) / 145 MN/m
2
(MPa)
10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.

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Formulae used:
Let, State 1 indicates the entry of compressor.
State 2 indicates the exit of compressor.
State 3 indicates the exit from condenser.
State 4 indicates the entry to evaporator

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P = Pressure (bar)
T = Temperature (
0
C)
H = Specific enthalpy (kJ/kg)

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v = Specific Volume (m
3
/Kg)
n = Number of revolutions of energy meter disc.
t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)

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t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)
K = Energy meter constant = 3200 lmp / kWh
N = Speed of compressor = 2840 rpm
h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

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56 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2
h3 = Specific enthalpy at Pc and T3 (kJ/kg)
h4 = h3

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Stroke volume of compressor = (?/ 4) d
2
l = 12.58 x 10
-6
m

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3

1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar
2. Average condenser pressure, Pc = (P2 + P3) / 2 bar
3. Heater input, Qe = (n / t1) x (3600 / k) kW

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4. Compressor input, W = (n / t2) x (3600 / k) kW
5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1
6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)
7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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57 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

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Sl.
No.

Initial

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Temp.
of water

Final
Temp.

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of water
Duration
of exp.

Delivery

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pressure

Delivery
Temp.

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Condense
Outlet
Pressure

Condense

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Outlet
Temp.


Pressure

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after
throttling

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Temp.
After
Throttli

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ng


Suction
pressur

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e
Suction
Temp.

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Time for
10 rev. of
compress

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or energy
meter

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Height
of water
in the
vessel

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58 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
Load Test with Capillary tube as expansion device:
1. Fill the chilled water calorimeter with pure water so that the evaporative coils are
fully immersed.

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2. Select the capillary tube line by opening the shut-off valve on this line and closing
the one on the thermostatic expansion valve line. The solenoid switch is switched OFF.
3. Start the compressor and run for some time so that the chilled water temperature
is lowered to the given test temperature.
4. Switch on the heater and slowly increase the power.

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5. Allow The temperature in water calorimeter to reach the equilibrium
temperature.
6. Connect energy meter to motor and heater by the selector switch one after another
and note down the time taken for 10 pulses of the energy meter disc.
7. Note down the pressure and temperature readings at locations 1,2,3 & 4 as

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mentioned.
8. Switch OFF the heater and the mains.
Result:
The load test on a refrigeration test rig was conducted and the results are as follows.
1. Actual C.O.P. of the system =____________.

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2. Rhetorical C.O.P. of the system = ___________.
3. Volumetric Efficiency = ___________.

Outcome:
From this experiment, conducting the load test on a refrigeration test rig and finding out the

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volumetric efficiency and co-efficient of performance for any type of refrigerant is learnt and this experiment
could be used in the areas such as Refrigerator and Air Conditioning.
Applications:
Refrigerator, Air Conditioning.

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59 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? COP
2. Which thermodynamic cycle is used in air conditioning of airplanes using air as refrigerant?
3. Define ? Ton of Refrigeration

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4. What is meant by refrigeration?
5. What is meant by air conditioning?
6. What are the four important properties of a good refrigerant?
7. How does the actual vapour compression cycle differ from that of the ideal cycle?
8. Name any four commonly used refrigerants.

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9. What are the expansion devices used in a vapour compression plant?
10. Why throttle valve is used in place of expansion cylinder for vapour compression refrigerant machine?
11. What are the merits of air refrigeration system?
12. What are the demerits of air refrigeration system?
13. Define ? Refrigerant

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14. What is net refrigerating effect of the refrigerant?
15. What are the methods to obtain sub cooling of refrigerant?

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Viva ? voce

60 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.12 EXPERIMENTS ON PSYCHROMETRIC PROCESS

Aim:

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To conduct an experiment on psychrometric processes with air conditioning system
Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch

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(iv) Digital anemometer
(v) Experimental setup
Description:
The test rig consist of
1. An air duct support of stand

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2. A blower to set up air flow through the duct along with a speed control to vary the
velocity of air.
3. A heater to rise the air temperature with regulator and energy meter.
4. Water spray, collecting tray, reservoir with gauge pump.
5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.

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(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after cooling coil).
6. The test rig consist of compressor, condenser unit placed inside trolley and fitted
with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for
condenser and (iv) Liquid receiver.
7. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and

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corrosion damage.

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61 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Observation Table: I

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Precautions:
1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence
avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kw only for the motor
circuit.
2. Natural air currents in the room if in the direction of air duct may defect the experimental results and

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hence the duct should be placed such that no wind from doors, windows, fan and cooling air from
other test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan
and should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase
beyond 240 psi.
3. Never exceed dry bulb temperatures of 40

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0
C after the heater (station 2) otherwise the air duct may be
damaged.
4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may
exceed its maximum of 32

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0
C and calibration may be affected.
5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not
running this will lead to rise in temperature at the heater and may damage the heater and the air duct.
6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their

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duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.
7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer
is placed inside the reservoir at the top. This may have to the cleaned when necessary.
8. Do not open the gate valve fully otherwise water may be splashed outside and the waster
measurement may be in error.

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S.
N
o
Inlet temp
Outlet

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temp
Pressu
re
P1
Tem

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p.
T1
Pressu
re
P2

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Temp.
T2
Pressu
re
P3

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Tem
p.
T3

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Pressu
re
P4

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Temp.
T4
Energy
for 10

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revolutio
ns
Twet Tdry Twet Tdry Lb/in
o
C Lb/in

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o
C Lb/in
o
C Lb/in
o

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C


62 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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9. If the low pressure cut out comes in to action, it means that the Freon charge is insufficient and may
have to be filled up. The suction pressure should never go below 2 psi as otherwise the compressor
seals will be damaged and air and moisture may enter the system.
10. The refrigerant strainer placed on the front panel should always be warm. If it cools and moisture
condenser on it, then the strainer might have to be charged by an experienced refrigeration

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mechanics.
11. The refrigerating system can work continuously for 2 hours, however if the room temperature is above
25
0
C the condenser may be heated up and the delivery pressure may rise. Do not exceed 240 psi.

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Pour one or two glasses of drinking water over the fins of the condenser in order to reduce the
delivery pressure.
12. After some months of operation the compressor may have to be topped up with oil and some quantity
of Freon-22 may have to be charged by an experienced mechanics.
13. See that distilled water is filled up in the plastic dishes provided under the wet bulb thermometers and

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that the wicks are in tact otherwise erroneous readings may be obtained. These thermometers will
show correct readings only when the fan is in operation.
14. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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Formulae used:
1. Corresponding to the dry and wet bulb temperature at all the stations obtain the specific enthalpy and
specific humidity values from psychrometric chart.
i.e., h1 and w1 at tb1 and tw1 and so on.
2. Air flow rate, ma = (A x V) / v4 Kg / sec

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Where, A = Area of duct at outlet in m
2
(0.46 m x 0.086 m)
V = Air velocity ( m / sec)
V4 = Specific volume of moist air at station 4 using psychometric chart m

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3
/Kg
3. Moisture added from psychrometric chart, mw1 = ma (w3-w2) Kg / sec.
Where, w3 = Specific humidity at station 3
w2 = Specific humidity at station 2

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4. Cooling effect produced on air, Qe = ma (h3 ? h4) kW.
Where, h3 = Specific enthalpy at state 3 kJ/kg
h4 = Specific enthalpy at state 4 kJ/kg
5. Moisture condensed, mcl = ma (w3 ? w4) kg/sec
Where, w3 = Specific humidity at station 3

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w4 = Specific humidity at station 4

63 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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1. Fill water in the wet bulb temperature probe trays.
2. Start the main.
3. Start the blower and run it the required speed by keeping the speed regulator at
position.
4. Start the spray pump and open the gate valve suitably.

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5. Start the heater.
6. Select the expansion device (Capillary tube / Thermostatic expansion valve)
7. Start the cooling compressor.
8. Wait for some time till thermometers shown practically constant readings and note down the
following readings:

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(i) Dry bulb temperatures tdb1, tdb2, tdb3, tdb4.
(ii) Wet bulb temperatures twb1, twb2, twb3, twb4.
(iii) Spray water temperature, ts
(iv) Surface temperature of cooler, tm ( at control panel)
(v) Pressure gauge reading, pd ( at control panel)

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(vi) Compound gauge reading, Ps ( at control panel)
(vii) Level reduction?l? in spray reservoir (mm) during 5 min.
(viii) Amount of condensate collected ?lc?, in a measuring jar at cooler tray during a
run of 5 minutes at constant conditions.
(ix) Time in second ?SH? for 10 pulses of the energy meter disc connected to the

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heater.
(x) Time in seconds Sc for 10 pulses of the energy meter disc connected to cooler
compressor.
Result:
Experiment on psychrometric processes with air conditioning system was drawn

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Outcome:
From this experiment, conducting the test on psychrometric processes with air
conditioning system is learnt and this experiment could be used in all types of air conditioning systems.

Applications:

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Air Conditioning.



64 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the commonly used unit of refrigeration?
2. Distinguish between summer air conditioning and winter air conditioning.

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3. Define ? RSHF Line
4. Define ? By Pass Factor of a Heating Coil
5. What is the effect of sub cooling a refrigerant in a vapour compression cycle?
6. What is the function of analyzer and rectifier in an absorption system?
7. What is the purpose of generator assembly in vapour absorption refrigeration system?

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8. State the substance used in the Lithium Bromide system and their functions.
9. Differentiate wet compression from dry compression.
10. Define ? Apparatus Dew Point
11. What is meant by dew point temperature?
12. Define ? Wet Bulb Temperature

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13. Define ? Degree of Saturation
14. What is meant by specific humidity?
15. Define ? Relative Humidity

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Viva ? voce

65 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.13

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PERFORMANCE TEST ON A RECIPROCATING
AIR COMPRESSOR

Aim:

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To conduct a load test on the 2 - stage reciprocating air compressor to determine the isothermal and
volumetric Efficiencies at various delivery pressures

Apparatus required:
* Air compressor with accessories.

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* Stop watch.
Description:
Two stage air compressors is a reciprocating type driven by a prime mover. The test rig consist of a base on
which the tank is mounted. The outlet of the compressor is connected to the receiver. The suction is
connected to air tank with a calibrated orifice plate through a water manometer. The input to the motor is

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recorded by an energy meter. The temperature and pressure of the air compressed is indicated by a
thermometer and pressure gauge.
Specifications:
1. Air compressor:
* LP Bore, DLP = 63.0 mm.

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* HP Bore, DHP = 79.0 mm.
* Stroke, L = 80.0 mm.
* Speed, N = 1440 rpm (5 HP)
* Effective radius = 0.193 m
2. Air receiver capacity = 0.33 m3

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3. Orifice, diameter, d0 = 12 mm
4. Orifice area,. A0 : ?d0
2
/ 4 = ----------- m
2

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5. Coefficient of discharge C d. = 0.6
6. Energy-meter constant = 200 rev / kWh

66 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I

Observation Table: II
Sl.

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No.
Actual
Discharge
Va
Theoritical

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Discharge
Vt
Volumetric
Efficiency
?

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Power
Input

Output
Power

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Overall
Efficiency
?0
Isothermal

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Workdone
IwD
Polytropic
Workdone
PwD

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Isothermal
Efficiency
?iso
m
3

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/sec m
3
/sec % kW kW % J/Kg J/Kg %

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Sl.
No.
Pressure
p
Manometer

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h1
Manometer
h2
Time for 5 revolutions Energy meter Speed of the compressor Temperature
T1

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Temperature
T1
Kg/cm
2
Cm cm sec rpm

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o
C
o
C

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67 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:

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1. Check whether manometer is filled with water up to the required level.
2. The maximum pressure in the receiver tank should not exceed 12 kg / cm
2

Procedure:

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1. Ensure that gauge pressure in the tank is zero.
2. Start the compressor. Read the receiver pressure gauge for a particular pressure.
3. Maintain the pressure constant by adjusting the outlet valve.
4. Note down the manometer reading and time taken for 3 revolution of the energy
Formulae used:

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1. Density of air at RTP:
? RTP = ? NTP X 273 Kg/ m
3

(273 + Room Temp)

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Where density of air at NTP = 1.293 Kg/ m
3
.

2. Air head causing flow:

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ha RTP = (h1 - h2) x ? water m
?a RTP
Where,
(h1- h2) = Difference in manometer liquid, in m.

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3. Actual volume at RTP:
Va RTP = C.d x Ao x ? 2 g ha RTP
Where,
C d= Coefficient of discharge = 0.6.
A o = Area of orifice = ?(d0)

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2
m
2
.
4

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Diameter of orifice d o = 0.01 m.
4. Actual volume at NTP:
Va NTP = VaRTP x T NTP
T RTP
Where,

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T NTP = Normal temp - 273
o
k
T RTP = Room temp -
o

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c (273 + TROOM )

68 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

5. Theoretical Volume of air: (at intake conditions)

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V T = ?D
2
x L x Nc m
3
/ sec.

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4 x 60
D = LP Bore diameter = 88.5 mm.
L = Stroke length = 88.9 mm.
Nc = Compressor speed rpm.
6. Volumetric Efficiency:(for LP stage)

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?vol = Va NTP x 100%
Vt
7. Shaft Input through Energy meter:

= 1 x n x ?t x ?m x 3600 kw.

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( Ec x t )
Where,
Ec = Energy meter constant = 200 rev / kWh
?t = Efficiency for transmission = 0.95.
? m = Efficiency for motor = 0.90.

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t = Time for 'n' revolution of energy meter disc.
n = no. of rev. of Energy meter disc.

8. Isothermal power:
= Pa x Va RTP x log e (R) W

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1000
Pa = Atmospheric pressure in N/ m
2
= 1.01325 x 10
5

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N / m
2
.
R = (Pressure gauge reading + atmospheric pressure)
atmospheric pressure.

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9. Isothermal efficiency:
? ISO = Isothermal power x 100%
Shaft input

Result:

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The values of isothermal and volumetric efficiency at various delivery pressures have been studied &
graph between Pressure Vs Volumetric efficiency and Pressure Vs Isothermal efficiency are drawn.


69 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Outcome:
From this experiment, conducting the load test on two stage reciprocating air compressor for
determining the isothermal and volumetric Efficiencies at various delivery pressures is understood and this
experiment could be used in the areas such as Refrigerator, Air Conditioning, IC engines, etc.

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Applications:
Refrigerator, Air Conditioning, IC engines.

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1. How are air compressors classified?
2. Define ? Isothermal Efficiency of Air Compressor
3. What is meant by FAD (Free Air Delivery)?
4. What is meant by perfect inter-cooling?
5. Define ? Clearance Ratio of an Air Compressor

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6. List out the applications of compressed air.
7. What are the types of air compressors?
8. What is meant by single acting compressor?
9. What is meant by double acting compressor?
10. What is meant by single stage compressor?

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11. What is meant by multi stage compressor?
12. Indicate the applications of reciprocating compressors in industry>
13. Define ? Mechanical Efficiency
14. What is meant by compression ratio?
15. What are the factors that affect the volumetric efficiency of a reciprocating compressor?

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Viva ? voce

70 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.14

PERFORMANCE TEST IN A HC REFRIGERATION
SYSTEM

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Aim:

To conduct the performance test on Vapour Compression Refrigeration System and to determine the
Coefficient of Performance using solenoid valve by throttling method

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Description:

In this system the working fluid is a HC out of a refrigeration system. The HC compression system is most
important system from the view point of commercial and domestic utility. The HC refrigerant at low temp and

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pressure enters the reciprocating compressor, where it is compressed isentropically and subsequently its temp
and pressure increases considerably. This HC after leaving the compressor enters the condenser where it is
cooled into low temperature. Then it is sucked by reciprocating compressor and is thus repeated.
Formula used:

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Actual COP = refrigerant effect
I/p energy to compressor
Refrigerant effect = mxCpx ? T
t
m - mass of water (kg)

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Cp - Sp. Heat of water (4.2 kJ/kg K)
?T ? decrease in temp (Ti-Ts)
t - timetaken duration of expt (sec)

Energy input =n x 3600 /k x t

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n ? number of revolutions in energy meter
t ? time taken of ?n? revolutions
k ? energy meter constant (3200)

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71 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:

Pressure of the refrigerant (Mpa) Temperature Time for n?

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rev of
energy
meter in
sec
P1 P2 P3 P4 Circulating fluid

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temp
Refrigerant temp

Ti Tf T1 T2 T3 T4

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72 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Model calculation:

Actual COP = refrigerant effect

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I/p energy to compressor

Refrigerant effect = mxCpx ? T
t
m - mass of water (kg)

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Cp - Sp. Heat of water (4.2 kJ/kg K)
?T ? decrease in temp (Ti-Ts)
t - time taken duration of experiment (sec)
Refrigerating effect = 8x4.2x (27-6)/1200=0.588 kw

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Energy input = n x 3600
n ? Number of revolutions in energy meter
t ? Time taken of ?n? revolutions
k ? Energy meter constant
=3 x 3600/(1200 x 54)

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=0.166 kW
Actual COP = refrigerant effect
I/p energy to compressor
= 0.588/0.166
=3.526

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Result:

The experiment was conducted successfully and coefficient of performance was found out is _______.

Outcome:

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From this experiment, conducting the performance test on Vapour Compression Refrigeration
System and to determine the Coefficient of Performance using solenoid valve by throttling method is
understood and this experiment could be used in the areas such as Refrigerator and Air Conditioning systems.
Applications:
Refrigerator, Air Conditioning.

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73 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the difference between air conditioning and refrigeration?
2. Write any three important properties of a good refrigerant.
3. What is the function of analyzer and rectifier in an absorption system?
4. How does humidity affect human comfort?
5. What is the commonly used unit of refrigeration?

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6. Distinguish between summer air conditioning and winter air conditioning.
7. Define ? RSHF Line
8. Define ? By Pass Factor of a Heating Coil
9. What is the effect of sub cooling a refrigerant in a vapour compression cycle?
10. What is the function of analyzer and rectifier in an absorption system?

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11. What is the purpose of generator assembly in vapour absorption refrigeration system?
12. State the substance used in the Lithium Bromide system and their functions.
13. Differentiate wet compression from dry compression.
14. Define ? Apparatus Dew Point
15. What is meant by dew point temperature?

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16. Define ? Wet Bulb Temperature
17. Define ? Degree of Saturation
18. What is meant by specific humidity?
19. Define ? Relative Humidity
20. What is meant by dew point temperature?

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Viva ? voce
FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart

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and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION

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VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence

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To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design

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products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies

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5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering

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2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools

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6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms

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9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder

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4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant

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9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system

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12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection

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experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.

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12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC

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Boiler.



COURSE OBJECTIVES

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COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS

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1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11

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3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21

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5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31

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7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47

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CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14

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Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate

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method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters

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together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples

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No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2

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(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help

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of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:

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1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm

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6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100

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0
C
9. Maximum temperature of the hot plate = 170
0
C

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10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V

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15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0

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C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter
V

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Ammeter
A
Main heater (
0
C) Test Plate (

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0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:

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1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single

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phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.

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8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.

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3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?

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8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?

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13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?

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18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:

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To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple

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(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.

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There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.

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4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.

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4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging

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k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:

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Sl.
No.
Voltage
(V)
Current

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(A)
Heater Temperature
(
0
C)

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Asbestos Temperature
(
0
C)
Saw dust

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Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos

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layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:

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The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)

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6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?

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11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.

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16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical

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tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which

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in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.

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The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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Schematic view of the test set-up:

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mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch

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Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples

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6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}

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Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W

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Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L
3

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?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v
2

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is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid

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v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity

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?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.

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hL / k = 0.56 (Gr.Pr)
0.25
for 10
4
< Gr.Pr.<10

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8

hL / k = 0.13 (Gr.Pr)
1/3
for 10

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8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).

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3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:

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The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m

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2
K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing

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heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?

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5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)

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10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness

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15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?

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20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:

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To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer

Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air

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stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of

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orifice meter and the water manometer fitted on the board.


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Tabulations:

Sl. No. Voltage Current Temperature in (

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0
C)
Manometer
reading of water
in h in meter

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(V) (A)
T1

T2

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T3

T4

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T5

T6

h1

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cm
h2
cm

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor

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5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0
C

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(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:

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1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.

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6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.

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2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. The rate at which air is getting heated is calculated as

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qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o

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C)
= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate

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Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m
3
/hr

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3. ha = qa /A(Ts- Ta) W / m
2
K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m

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2

Ta = Average temperature of air = (T1 + T6)/2
o
C

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Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C
Cd = 0.64
H = Difference of water level in manometer m

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?w Density of water = 1000 Kg/m
3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

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d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

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using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2

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)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o
C

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5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

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27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k

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? = Viscosity Ns/m
2

k = Thermal conductivity of fluid W/m
2

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K
Nu = 0.023 (Re)
0.8
(Pr)
0.4

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Bulk mean temperature = (T1 + T6)/2

Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.

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hactual = -------------- W/m
2
K
htheoritical = -------------- W/m
2

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K

Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?

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3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?

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8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection

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13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

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Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,

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the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure

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temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat

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flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm

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2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.

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2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

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30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature

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gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:

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Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R

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Tabulation:
Sl.No. Voltmeter
reading
(V)
Ammeter

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reading
(A)
T1
(
0

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C)
T2
(
0
C)

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T3
(
0
C)
T4

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(
0
C)
T5
(

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0
C)
T6
(
0

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C)
T7
(
0
C)

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T8
(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Composite wall apparatus set-up

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Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W

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c. Asbestos section = ------------W

Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure

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Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?

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5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.

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9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

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33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

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DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

Aim:
To find out the thermal conductivity of insulating powder by conduction

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Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A

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multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

Procedure:

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1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.

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5. Repeat the experiments for different power inputs.


The readings are tabulated below

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Sl.No. Voltmeter
reading( V)
Ammeter
reading (A)
T1

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(
0
C)
T2
(

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0
C)
T3
(
0

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C)
T4
(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm

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The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Fig. 1 Apparatus of thermal conductivity of insulating powder

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[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

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Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam

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boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity

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3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.

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8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?

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13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?

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18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

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HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

Aim:

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To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is

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measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:
Sl.

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No.
V I

Fin Temperatures (
0

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C)
Ambient Temp
(
0
C)

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Manometer
Reading
(V)

(A)

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T1 T2 T3 T4 T5 T6 T7 T8
h1
cm
h2

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cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Duct size = 150 mm x 100 mm.

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2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

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Schematic view of the test set-up:



zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5

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10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C
12. Temperature indicator = 0 ? 300

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0
C
(With compensation of ambient temperature up-to 50
0
C)

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13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8

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Brass Pin Fin
Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.

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4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:

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Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.

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4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2

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Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m

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3
/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m

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3

?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s

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2

Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s

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Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

A = area of the duct

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4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.

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(T1 + T6) / 2
o
C
5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number

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6. Nusselt Number:
Nu = CRe
m
(Pr)
0.33

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7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk
m= ?(hp/kA)

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A = area of fin = (? x D
2
) /4
L = Length of the fin
Tw ? average temperature

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T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________

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Heat transfer, Q = ___________ W

Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.


40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer

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6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?

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11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.8

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DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

Aim:

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To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch

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(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water

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between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.

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When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere

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3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg

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8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C
= (or) 0.1 Kcal / kg
0

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C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

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11. Temperature indicator digital 0.1
0
C L.C 0 - 200
0

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C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water
Precautions:

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Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4

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? Td
4
)
Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)

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Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

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43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulations:
Proc
edur

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e:
1. H
eat the
water
in the

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tank by
the immersion heater up to a temperature of about 90
0
C.
2. Remove the disc, D before pouring the hot water in the jacket.

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3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.

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6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m

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2
k
4
.

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Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using

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boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

Sl. No.

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Hemisphere Temperature(
0
C) Avg. Temp.
of the
Hemisphere

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(Th)
T4
Steady
Temp. of
Disc

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T0 (Td)
Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number
5. State Wien?s displacement law.

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6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation
10. What are the various modes of condensation?

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11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.9

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DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

Aim:

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To measure emissivity of the test plate surface at various temperature
Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The

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temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.
Specifications:
1. Heater input to black plate W1 = V1 x I1 W

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2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V

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6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300

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0
C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.

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Tabulation:
Sl.
No
Voltage

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Current

Black body
temp(
0

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C)
Avg.
temp.

Polished body

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temp (
0
C)
Avg.
temp.

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Enclosure
Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts

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4
? Ta
4
) A
Eb ? E = (W1 ? W2) / ? (Ts

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4
? Ta
4
) A
E = Eb ? {(W1 ? W2) / ? (Ts

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4
? Ta
4
) A}
Where,

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W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd
2
m

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2

T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)

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Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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? = Stefan boltzman constant = 5.67 x 10
-8
W/m
2
K

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4


Schematic view of the test set-up:

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Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by

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the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

Results:

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The emissivity of the test plate surface is found to be _____________.
Outcome:
From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

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48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Emissivity
2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?

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4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?
6. What is meant by shape factor?
7. Define ? Radiation
8. What is meant by monochromatic emissive power?

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9. Define ? Emissive Power
10. What is meant by absorptivity?
11. Define ? Black Body
12. What is meant by transmissivity?
13. State Plank's distribution law

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14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

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49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.10

EFFECTIVENESS OF PARALLEL / COUNTER

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FLOW HEAT EXCHANGE

Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:

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(i) Experimental Setup
(ii) Stop watch
(iii) Thermometer
Theory:
Heat exchangers are classified in three categories:

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1. Transfer type
2. Storage type
3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.

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The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water

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which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:

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1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50

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0
C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100
0
C - 2 Nos.

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7. Measuring flask = 0 ? 1000 CC

50 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

8. Geyser: single phase type to obtain hot water supply

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9. Thermo Cole insulation for outer pipe.
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Tabulations:

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Sl.
No.
Flow Hot Fluid (
0
C) Cold Fluid (

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0
C)
Time for
collection of
hot fluid

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Kg/sec
Time for
collection
of cold fluid
Kg/sec

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1 Parallel flow
Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)

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1. Area of the pipe A = ? (D ? d) L
Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube
L = Length of the tube

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2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

51 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Where, m = mass flow rate Kg/ sec.

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m = ?v/t, ? = density of water and t = time taken for hot water
Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet
Tho = Temperature of hot water outlet

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3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W
Where, m = mass flow rate
Cp = Specific heat of capacity
Tco = Temperature of cold water inlet
Tci = Temperature of cold water outlet

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4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W
Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)
?Tm = (?Ti - ?To) / In (?Ti/?To)
Where, ?To = Tho ? Tco

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?Ti = Thi ? Tci
6. Over all heat transfer coefficient
h = Q?/?Tm A W/m
2
K

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where Q? = (Qa + Qc) / 2

Procedure:
1. Place the thermometers in position and note down their readings when they are at room temperature and
no water is flowing at either side. This is required to correct the temperature.

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2. Start the flow on hot water side.
3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.
5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.
6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.

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7. Keeping the flow rates same, wait till the steady state conditions are reached.
8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.
10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

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52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Result:
1. The values of effectiveness of heat exchanger were found as

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(i) Parallel flow = ________.
(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)
(i) Parallel flow = ________.
(ii) Counter flow = _________.

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Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow
heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat
exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Heat Exchanger
2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?
4. Write about the merits of drop wise condensation.
5. What is meant by film wise and drop wise condensation?

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6. What is meant by effectiveness?
7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?
9. Distinguish between regenerator and recuperates.
10. What is meant by parallel flow heat exchanger?

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11. What is meant by counter flow heat exchanger?
12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?
Viva ? voce

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53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.11

DETERMINATION OF COP OF A REFRIGERATION

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SYSTEM

Aim:
To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration
system

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Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Experimental setup

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Description:
1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a
reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.
2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated
wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a

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low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the
temperature of chilled water. The above unit is located on the trolley behind front panel.
3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic
expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum
strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure

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gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high
pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy
meter to measure the power consumed either by hater or by compressor.

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54 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
A. A compressor condenser unit placed inside trolley and fitted with
1. R-134a reciprocating compressor
2. Condenser

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3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan
4. A receiver with angle check valve
B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity
placed inside a well insulated wooden box and provided with
5. Evaporator coil

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6. Stirrer
7. Electric heater 230 V, A.C.
8. The sensing bulb of low temperature thermostat.
9. A high temperature thermostat.
10. A Thermometer to measure the chilled water temperature

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C. The front panel on which are mounted the following
11. Capillary expansion tube with isolating valve.
12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator
and isolating valve
13. Drier cum strainer and sight glass

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14. Thermostat at inlet and outlet of both evaporator and condenser
15. Pressure gauge at inlet and outlet of evaporator and condenser
16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out
17. Heat power regulator switch and regulator
18. Energy meter to measure the power consumed either by hater or by compressor.

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55 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.
2. The heater regulator should be switched off whenever not in use. Heating water beyond 40
0
C may lead to

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permanent damage of the entire system. A high temperature cut off thermostat is provided in the water
chiller, to cut off the heater beyond 30
0
C.Check the setting of the same before operation.
3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.

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4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.
5. The solenoid thermostat is adjusted to cut at 15
0
C and cut in at 10
0

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C of the chilled water. Do not alter the
same.
6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.
7. The space near the condenser should permit good ventilation to aid proper fan performance.
8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked

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in
0
F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,
calibrated in SI units, are not available.)
9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to

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obtain the pressure in MN/m
2
.e.g. P = x psig
= (x + 14.7) psia
= (x + 14.7) / 145 MN/m

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2
(MPa)
10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.
Formulae used:
Let, State 1 indicates the entry of compressor.

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State 2 indicates the exit of compressor.
State 3 indicates the exit from condenser.
State 4 indicates the entry to evaporator
P = Pressure (bar)
T = Temperature (

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0
C)
H = Specific enthalpy (kJ/kg)
v = Specific Volume (m
3

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/Kg)
n = Number of revolutions of energy meter disc.
t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)
t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)
K = Energy meter constant = 3200 lmp / kWh

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N = Speed of compressor = 2840 rpm
h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

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h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2
h3 = Specific enthalpy at Pc and T3 (kJ/kg)
h4 = h3
Stroke volume of compressor = (?/ 4) d
2

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l = 12.58 x 10
-6
m
3

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1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar
2. Average condenser pressure, Pc = (P2 + P3) / 2 bar
3. Heater input, Qe = (n / t1) x (3600 / k) kW
4. Compressor input, W = (n / t2) x (3600 / k) kW
5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1

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6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)
7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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57 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I


Sl.

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No.

Initial
Temp.
of water

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Final
Temp.
of water
Duration

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of exp.

Delivery
pressure

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Delivery
Temp.

Condense
Outlet

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Pressure

Condense
Outlet
Temp.

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Pressure
after
throttling

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Temp.
After
Throttli
ng

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Suction
pressur
e
Suction

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Temp.

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Time for
10 rev. of
compress
or energy
meter

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Height
of water

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in the
vessel

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58 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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Load Test with Capillary tube as expansion device:
1. Fill the chilled water calorimeter with pure water so that the evaporative coils are
fully immersed.
2. Select the capillary tube line by opening the shut-off valve on this line and closing
the one on the thermostatic expansion valve line. The solenoid switch is switched OFF.

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3. Start the compressor and run for some time so that the chilled water temperature
is lowered to the given test temperature.
4. Switch on the heater and slowly increase the power.
5. Allow The temperature in water calorimeter to reach the equilibrium
temperature.

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6. Connect energy meter to motor and heater by the selector switch one after another
and note down the time taken for 10 pulses of the energy meter disc.
7. Note down the pressure and temperature readings at locations 1,2,3 & 4 as
mentioned.
8. Switch OFF the heater and the mains.

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Result:
The load test on a refrigeration test rig was conducted and the results are as follows.
1. Actual C.O.P. of the system =____________.
2. Rhetorical C.O.P. of the system = ___________.
3. Volumetric Efficiency = ___________.

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Outcome:
From this experiment, conducting the load test on a refrigeration test rig and finding out the
volumetric efficiency and co-efficient of performance for any type of refrigerant is learnt and this experiment
could be used in the areas such as Refrigerator and Air Conditioning.

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Applications:
Refrigerator, Air Conditioning.

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59 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? COP
2. Which thermodynamic cycle is used in air conditioning of airplanes using air as refrigerant?
3. Define ? Ton of Refrigeration
4. What is meant by refrigeration?
5. What is meant by air conditioning?

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6. What are the four important properties of a good refrigerant?
7. How does the actual vapour compression cycle differ from that of the ideal cycle?
8. Name any four commonly used refrigerants.
9. What are the expansion devices used in a vapour compression plant?
10. Why throttle valve is used in place of expansion cylinder for vapour compression refrigerant machine?

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11. What are the merits of air refrigeration system?
12. What are the demerits of air refrigeration system?
13. Define ? Refrigerant
14. What is net refrigerating effect of the refrigerant?
15. What are the methods to obtain sub cooling of refrigerant?

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Viva ? voce

60 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.12 EXPERIMENTS ON PSYCHROMETRIC PROCESS

Aim:
To conduct an experiment on psychrometric processes with air conditioning system
Apparatus required:

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(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Digital anemometer
(v) Experimental setup

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Description:
The test rig consist of
1. An air duct support of stand
2. A blower to set up air flow through the duct along with a speed control to vary the
velocity of air.

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3. A heater to rise the air temperature with regulator and energy meter.
4. Water spray, collecting tray, reservoir with gauge pump.
5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.
(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after cooling coil).
6. The test rig consist of compressor, condenser unit placed inside trolley and fitted

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with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for
condenser and (iv) Liquid receiver.
7. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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61 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I

Precautions:
1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence

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avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kw only for the motor
circuit.
2. Natural air currents in the room if in the direction of air duct may defect the experimental results and
hence the duct should be placed such that no wind from doors, windows, fan and cooling air from
other test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan

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and should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase
beyond 240 psi.
3. Never exceed dry bulb temperatures of 40
0
C after the heater (station 2) otherwise the air duct may be

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damaged.
4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may
exceed its maximum of 32
0
C and calibration may be affected.

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5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not
running this will lead to rise in temperature at the heater and may damage the heater and the air duct.
6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their
duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.
7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer

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is placed inside the reservoir at the top. This may have to the cleaned when necessary.
8. Do not open the gate valve fully otherwise water may be splashed outside and the waster
measurement may be in error.
S.
N

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o
Inlet temp
Outlet
temp
Pressu

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re
P1
Tem
p.
T1

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Pressu
re
P2
Temp.
T2

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Pressu
re
P3

Tem

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p.
T3


Pressu

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re
P4


Temp.

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T4
Energy
for 10
revolutio
ns

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Twet Tdry Twet Tdry Lb/in
o
C Lb/in
o
C Lb/in

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o
C Lb/in
o
C

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62 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

9. If the low pressure cut out comes in to action, it means that the Freon charge is insufficient and may
have to be filled up. The suction pressure should never go below 2 psi as otherwise the compressor

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seals will be damaged and air and moisture may enter the system.
10. The refrigerant strainer placed on the front panel should always be warm. If it cools and moisture
condenser on it, then the strainer might have to be charged by an experienced refrigeration
mechanics.
11. The refrigerating system can work continuously for 2 hours, however if the room temperature is above

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25
0
C the condenser may be heated up and the delivery pressure may rise. Do not exceed 240 psi.
Pour one or two glasses of drinking water over the fins of the condenser in order to reduce the
delivery pressure.

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12. After some months of operation the compressor may have to be topped up with oil and some quantity
of Freon-22 may have to be charged by an experienced mechanics.
13. See that distilled water is filled up in the plastic dishes provided under the wet bulb thermometers and
that the wicks are in tact otherwise erroneous readings may be obtained. These thermometers will
show correct readings only when the fan is in operation.

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14. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

Formulae used:
1. Corresponding to the dry and wet bulb temperature at all the stations obtain the specific enthalpy and

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specific humidity values from psychrometric chart.
i.e., h1 and w1 at tb1 and tw1 and so on.
2. Air flow rate, ma = (A x V) / v4 Kg / sec
Where, A = Area of duct at outlet in m
2

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(0.46 m x 0.086 m)
V = Air velocity ( m / sec)
V4 = Specific volume of moist air at station 4 using psychometric chart m
3
/Kg

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3. Moisture added from psychrometric chart, mw1 = ma (w3-w2) Kg / sec.
Where, w3 = Specific humidity at station 3
w2 = Specific humidity at station 2
4. Cooling effect produced on air, Qe = ma (h3 ? h4) kW.
Where, h3 = Specific enthalpy at state 3 kJ/kg

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h4 = Specific enthalpy at state 4 kJ/kg
5. Moisture condensed, mcl = ma (w3 ? w4) kg/sec
Where, w3 = Specific humidity at station 3
w4 = Specific humidity at station 4

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63 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Fill water in the wet bulb temperature probe trays.
2. Start the main.

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3. Start the blower and run it the required speed by keeping the speed regulator at
position.
4. Start the spray pump and open the gate valve suitably.
5. Start the heater.
6. Select the expansion device (Capillary tube / Thermostatic expansion valve)

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7. Start the cooling compressor.
8. Wait for some time till thermometers shown practically constant readings and note down the
following readings:
(i) Dry bulb temperatures tdb1, tdb2, tdb3, tdb4.
(ii) Wet bulb temperatures twb1, twb2, twb3, twb4.

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(iii) Spray water temperature, ts
(iv) Surface temperature of cooler, tm ( at control panel)
(v) Pressure gauge reading, pd ( at control panel)
(vi) Compound gauge reading, Ps ( at control panel)
(vii) Level reduction?l? in spray reservoir (mm) during 5 min.

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(viii) Amount of condensate collected ?lc?, in a measuring jar at cooler tray during a
run of 5 minutes at constant conditions.
(ix) Time in second ?SH? for 10 pulses of the energy meter disc connected to the
heater.
(x) Time in seconds Sc for 10 pulses of the energy meter disc connected to cooler

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compressor.
Result:
Experiment on psychrometric processes with air conditioning system was drawn
Outcome:
From this experiment, conducting the test on psychrometric processes with air

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conditioning system is learnt and this experiment could be used in all types of air conditioning systems.

Applications:
Air Conditioning.

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64 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the commonly used unit of refrigeration?
2. Distinguish between summer air conditioning and winter air conditioning.
3. Define ? RSHF Line
4. Define ? By Pass Factor of a Heating Coil

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5. What is the effect of sub cooling a refrigerant in a vapour compression cycle?
6. What is the function of analyzer and rectifier in an absorption system?
7. What is the purpose of generator assembly in vapour absorption refrigeration system?
8. State the substance used in the Lithium Bromide system and their functions.
9. Differentiate wet compression from dry compression.

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10. Define ? Apparatus Dew Point
11. What is meant by dew point temperature?
12. Define ? Wet Bulb Temperature
13. Define ? Degree of Saturation
14. What is meant by specific humidity?

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15. Define ? Relative Humidity

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Viva ? voce

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65 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.13

PERFORMANCE TEST ON A RECIPROCATING

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AIR COMPRESSOR

Aim:
To conduct a load test on the 2 - stage reciprocating air compressor to determine the isothermal and
volumetric Efficiencies at various delivery pressures

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Apparatus required:
* Air compressor with accessories.
* Stop watch.
Description:

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Two stage air compressors is a reciprocating type driven by a prime mover. The test rig consist of a base on
which the tank is mounted. The outlet of the compressor is connected to the receiver. The suction is
connected to air tank with a calibrated orifice plate through a water manometer. The input to the motor is
recorded by an energy meter. The temperature and pressure of the air compressed is indicated by a
thermometer and pressure gauge.

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Specifications:
1. Air compressor:
* LP Bore, DLP = 63.0 mm.
* HP Bore, DHP = 79.0 mm.
* Stroke, L = 80.0 mm.

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* Speed, N = 1440 rpm (5 HP)
* Effective radius = 0.193 m
2. Air receiver capacity = 0.33 m3
3. Orifice, diameter, d0 = 12 mm
4. Orifice area,. A0 : ?d0

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2
/ 4 = ----------- m
2

5. Coefficient of discharge C d. = 0.6

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6. Energy-meter constant = 200 rev / kWh

66 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

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Observation Table: II
Sl.
No.
Actual

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Discharge
Va
Theoritical
Discharge
Vt

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Volumetric
Efficiency
?
Power
Input

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Output
Power

Overall

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Efficiency
?0
Isothermal
Workdone
IwD

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Polytropic
Workdone
PwD
Isothermal
Efficiency

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?iso
m
3
/sec m
3

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/sec % kW kW % J/Kg J/Kg %


Sl.
No.

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Pressure
p
Manometer
h1
Manometer

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h2
Time for 5 revolutions Energy meter Speed of the compressor Temperature
T1
Temperature
T1

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Kg/cm
2
Cm cm sec rpm
o
C

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o
C

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67 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Check whether manometer is filled with water up to the required level.
2. The maximum pressure in the receiver tank should not exceed 12 kg / cm

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2

Procedure:
1. Ensure that gauge pressure in the tank is zero.
2. Start the compressor. Read the receiver pressure gauge for a particular pressure.

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3. Maintain the pressure constant by adjusting the outlet valve.
4. Note down the manometer reading and time taken for 3 revolution of the energy
Formulae used:
1. Density of air at RTP:
? RTP = ? NTP X 273 Kg/ m

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3

(273 + Room Temp)
Where density of air at NTP = 1.293 Kg/ m
3

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.

2. Air head causing flow:
ha RTP = (h1 - h2) x ? water m
?a RTP

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Where,
(h1- h2) = Difference in manometer liquid, in m.

3. Actual volume at RTP:
Va RTP = C.d x Ao x ? 2 g ha RTP

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Where,
C d= Coefficient of discharge = 0.6.
A o = Area of orifice = ?(d0)
2
m

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2
.
4
Diameter of orifice d o = 0.01 m.
4. Actual volume at NTP:

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Va NTP = VaRTP x T NTP
T RTP
Where,
T NTP = Normal temp - 273
o

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k
T RTP = Room temp -
o
c (273 + TROOM )

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68 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

5. Theoretical Volume of air: (at intake conditions)
V T = ?D
2

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x L x Nc m
3
/ sec.
4 x 60
D = LP Bore diameter = 88.5 mm.

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L = Stroke length = 88.9 mm.
Nc = Compressor speed rpm.
6. Volumetric Efficiency:(for LP stage)
?vol = Va NTP x 100%
Vt

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7. Shaft Input through Energy meter:

= 1 x n x ?t x ?m x 3600 kw.
( Ec x t )
Where,

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Ec = Energy meter constant = 200 rev / kWh
?t = Efficiency for transmission = 0.95.
? m = Efficiency for motor = 0.90.
t = Time for 'n' revolution of energy meter disc.
n = no. of rev. of Energy meter disc.

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8. Isothermal power:
= Pa x Va RTP x log e (R) W
1000
Pa = Atmospheric pressure in N/ m

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2
= 1.01325 x 10
5
N / m
2

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.
R = (Pressure gauge reading + atmospheric pressure)
atmospheric pressure.
9. Isothermal efficiency:
? ISO = Isothermal power x 100%

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Shaft input

Result:
The values of isothermal and volumetric efficiency at various delivery pressures have been studied &
graph between Pressure Vs Volumetric efficiency and Pressure Vs Isothermal efficiency are drawn.

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69 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Outcome:

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From this experiment, conducting the load test on two stage reciprocating air compressor for
determining the isothermal and volumetric Efficiencies at various delivery pressures is understood and this
experiment could be used in the areas such as Refrigerator, Air Conditioning, IC engines, etc.

Applications:

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Refrigerator, Air Conditioning, IC engines.


1. How are air compressors classified?
2. Define ? Isothermal Efficiency of Air Compressor

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3. What is meant by FAD (Free Air Delivery)?
4. What is meant by perfect inter-cooling?
5. Define ? Clearance Ratio of an Air Compressor
6. List out the applications of compressed air.
7. What are the types of air compressors?

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8. What is meant by single acting compressor?
9. What is meant by double acting compressor?
10. What is meant by single stage compressor?
11. What is meant by multi stage compressor?
12. Indicate the applications of reciprocating compressors in industry>

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13. Define ? Mechanical Efficiency
14. What is meant by compression ratio?
15. What are the factors that affect the volumetric efficiency of a reciprocating compressor?

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Viva ? voce

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70 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.14

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PERFORMANCE TEST IN A HC REFRIGERATION
SYSTEM


Aim:

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To conduct the performance test on Vapour Compression Refrigeration System and to determine the
Coefficient of Performance using solenoid valve by throttling method

Description:

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In this system the working fluid is a HC out of a refrigeration system. The HC compression system is most
important system from the view point of commercial and domestic utility. The HC refrigerant at low temp and
pressure enters the reciprocating compressor, where it is compressed isentropically and subsequently its temp
and pressure increases considerably. This HC after leaving the compressor enters the condenser where it is

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cooled into low temperature. Then it is sucked by reciprocating compressor and is thus repeated.
Formula used:

Actual COP = refrigerant effect
I/p energy to compressor

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Refrigerant effect = mxCpx ? T
t
m - mass of water (kg)
Cp - Sp. Heat of water (4.2 kJ/kg K)
?T ? decrease in temp (Ti-Ts)

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t - timetaken duration of expt (sec)

Energy input =n x 3600 /k x t
n ? number of revolutions in energy meter
t ? time taken of ?n? revolutions

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k ? energy meter constant (3200)


71 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulation:

Pressure of the refrigerant (Mpa) Temperature Time for n?
rev of
energy

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meter in
sec
P1 P2 P3 P4 Circulating fluid
temp
Refrigerant temp

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Ti Tf T1 T2 T3 T4

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72 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Model calculation:

Actual COP = refrigerant effect
I/p energy to compressor

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Refrigerant effect = mxCpx ? T
t
m - mass of water (kg)
Cp - Sp. Heat of water (4.2 kJ/kg K)
?T ? decrease in temp (Ti-Ts)

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t - time taken duration of experiment (sec)
Refrigerating effect = 8x4.2x (27-6)/1200=0.588 kw

Energy input = n x 3600
n ? Number of revolutions in energy meter

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t ? Time taken of ?n? revolutions
k ? Energy meter constant
=3 x 3600/(1200 x 54)
=0.166 kW
Actual COP = refrigerant effect

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I/p energy to compressor
= 0.588/0.166
=3.526
Result:

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The experiment was conducted successfully and coefficient of performance was found out is _______.

Outcome:
From this experiment, conducting the performance test on Vapour Compression Refrigeration
System and to determine the Coefficient of Performance using solenoid valve by throttling method is

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understood and this experiment could be used in the areas such as Refrigerator and Air Conditioning systems.
Applications:
Refrigerator, Air Conditioning.

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73 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the difference between air conditioning and refrigeration?
2. Write any three important properties of a good refrigerant.

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3. What is the function of analyzer and rectifier in an absorption system?
4. How does humidity affect human comfort?
5. What is the commonly used unit of refrigeration?
6. Distinguish between summer air conditioning and winter air conditioning.
7. Define ? RSHF Line

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8. Define ? By Pass Factor of a Heating Coil
9. What is the effect of sub cooling a refrigerant in a vapour compression cycle?
10. What is the function of analyzer and rectifier in an absorption system?
11. What is the purpose of generator assembly in vapour absorption refrigeration system?
12. State the substance used in the Lithium Bromide system and their functions.

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13. Differentiate wet compression from dry compression.
14. Define ? Apparatus Dew Point
15. What is meant by dew point temperature?
16. Define ? Wet Bulb Temperature
17. Define ? Degree of Saturation

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18. What is meant by specific humidity?
19. Define ? Relative Humidity
20. What is meant by dew point temperature?

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Viva ? voce

74 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.15

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PERFORMANCE TEST IN A FLUIDIZED BED
COOLING SYSTEM

Aim:

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To determine the performance test on cooling tower
Introduction:
The cooling tower is one of the most important device in chemical industries for example when the hot
water come from heat exchanger we use the cooling tower to cool it The purpose of cooling tower is to cool
relatively warm water by contacting with unsaturated air. The evaporation of water mainly provides cooling. In

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typical water cooling water tower warm water flows countercurrent to an airstream. Typically, the warm water
enters the top of the packed tower and cascades down through the packing , leaving at the bottom Air enters
at the bottom of the tower and flows upward through the descending water . The tower packing often consist of
slats of plastic or of packed bed. The water is distributed by troughs and overflows to cascade over slat
gratings or packing that provides large interfacial areas of contact between the water and air in the form of

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droplets and films of water. The flow of air upward through the tower can be induced by the buoyancy of the
warm air in the tower (natural draft) or by the action of a fan . The water cannot be cooled below the wet bulb
temperature. The driving force for the evaporation of water is approximately the vapour pressure of the water
less the vapour pressure it would have at the wet bulb temperature
Procedure:

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1. Introduce water and record its flow rate.
2. Switch ON the heaters on so that water is heated to the required temperature.
3. Introduce air and record its flow rate.
4. Wait for steady state then record steady state dry and wet bulb temperature of air at the entrance and
exit.

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5. Record the inlet and outlet temperature and flow rate of water also record temperature at different
stages.
Tabulation:

Sl.No. T1 (

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0
c) T2 (
0
c) T3 (
0

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c) Efficiency

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T1 = room temperature
FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?



DEPARTMENT OF

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MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

--- Content provided by FirstRanker.com ---

Name : _______________________________________

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Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

--- Content provided by FirstRanker.com ---

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VISION
MISSION
VISION
MISSION

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4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals

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To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them

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3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills

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To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering

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and to create awareness about the need for lifelong learning and pursuing advanced degrees

--- Content provided by FirstRanker.com ---

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME OUTCOMES (POs)

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On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship

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3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical

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environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination

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10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:

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1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall

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6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

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REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor

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14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus

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5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.

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10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at

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various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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CONTENTS


Sl.No.

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Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2

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Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3
Determination of heat transfer coefficient under natural convection from a

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vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27

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CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34

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8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51

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12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72

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ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

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Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:

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(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:

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The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.

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Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts

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on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:
1. Power input, Q = V ? A / 2 W

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2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:

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1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do

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not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm

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3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm

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8. Mean temperature range = 40
0
C ? 100
0
C

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9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)

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12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)

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17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C
19. Width of gap between two heater plates (x) = 2.5 mm

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20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter
V
Ammeter
A

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Main heater (
0
C) Test Plate (
0
C)

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T1 T2 T3 T4 T5 T6



Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.

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2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.

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5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

Outcome:

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From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

Applications:

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Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins

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5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?

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10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?

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15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?

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20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE

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APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:

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(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter

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Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:

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1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the

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experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:

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The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.

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L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.
No.

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Voltage
(V)
Current
(A)
Heater Temperature

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(
0
C)
Asbestos Temperature
(

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0
C)
Saw dust
Temperature (
0

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C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.

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3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by

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thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m

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2
-K

Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe

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apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?

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3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection

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8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?

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13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?

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18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

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Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:

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(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:

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The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is

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measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the

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relative motion of hot and cold fluid particles.

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Schematic view of the test set-up:
mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm

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2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300

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0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V

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8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

Tabulation:
Sl. No.

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Voltage Current Temperature of Thermocouple (
0
c)

V A

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T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2

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K
As = Area of heat transfer surface = ? x d x l m
2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7

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0
C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0

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C) ?
2. hL / k = A { g L
3
?T Cp ?/2v
2

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}
n

Where, hL / k are called Nusselt Number.
L

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3
g?T / v
2
is called Grashof number.
?Cp / k called Prandtl Number.

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A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid

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Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)

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0
K
-1

Where Tf = (Ts + Ta )/ 2

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For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25

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for 10
4
< Gr.Pr.<10
8

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hL / k = 0.13 (Gr.Pr)
1/3
for 10
8
< Gr.Pr.<10

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12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).

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5. Repeat the experiment at different heat inputs.

Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m

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2
K
Experimental = ______________ W/ m
2
K

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Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be

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found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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1. Define ? Grash of Number(Gr)

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2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness

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7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?

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12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.

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17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No. 4

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION

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FROM A TUBE

Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater

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is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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Tabulations:

Sl. No. Voltage Current Temperature in (
0
C)

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Manometer
reading of water
in h in meter

(V) (A)

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T1

T2

T3

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T4

T5

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T6

h1
cm
h2

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cm

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Specifications:
1. Pipe diameter outside (Do) = 40 mm

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2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C

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7. Temperature Indicator = Range 0 to 300
0
C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V

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9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.

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3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W

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Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.

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3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)

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Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o
C)
= T6 ? T1.

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2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di
2

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?2gH x (?w / ?a) m
3
/hr
3. ha = qa /A(Ts- Ta) W / m
2

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K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

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Ta = Average temperature of air = (T1 + T6)/2
o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o

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C
Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

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?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

d = diameter of orifice meter = 0.014 m

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g = acceleration due to gravity = 9.81 m/s
2

using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:

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Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature

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(T1 + T6)/2
o
C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number

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K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

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k = Thermal conductivity of fluid W/m
2
K
Nu = 0.023 (Re)

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0.8
(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

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Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m
2

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K
htheoritical = -------------- W/m
2
K

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Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.

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5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.

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10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?

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15. Define ? Momentum Thickness

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Viva ? voce

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29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:

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To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different

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materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A

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channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in

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series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm

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4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.

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3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as

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Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3

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Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter

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reading
(V)
Ammeter
reading
(A)

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T1
(
0
C)
T2

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(
0
C)
T3
(

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0
C)
T4
(
0

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C)
T5
(
0
C)

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T6
(
0
C)
T7

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(
0
C)
T8
(

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0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:

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The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

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Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. Define ? Heat Transfer

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2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?

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6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?
10. Define ? Heat Exchanger

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11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

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Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

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The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input

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power and dimmer stat is provided to vary the input power.

Procedure:

1. Switch on the unit and adjust the input power to the required extent.

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2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter
reading( V)

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Ammeter
reading (A)
T1
(
0

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C)
T2
(
0
C)

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T3
(
0
C)
T4

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(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the

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inner sphere, and the outer sphere respectively.


34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Fig. 1 Apparatus of thermal conductivity of insulating powder

[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

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Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

Outcome:

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From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?

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5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?

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10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)

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15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?

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20. What is meant by steady state heat conduction?

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Viva ? voce

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36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

HEAT TRANSFER FROM PIN-FIN APPARATUS

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(NATURAL AND FORCED CONVECTION MODES)

Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:

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(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is

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connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.

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Tabulations:
Forced convection:
Sl.
No.
V I

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Fin Temperatures (
0
C)
Ambient Temp

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(
0
C)
Manometer
Reading

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(V)

(A)

T1 T2 T3 T4 T5 T6 T7 T8

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h1
cm
h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm

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4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm

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7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.

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0
C
12. Temperature indicator = 0 ? 300
0
C

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(With compensation of ambient temperature up-to 50
0
C)
13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)

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15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8
Brass Pin Fin
Heater

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38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

16. Ammeter = 0 ? 2 A
Precautions:

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1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.

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6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:
Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,

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100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.

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5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)

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2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m
3
/s.

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Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m
3

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?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s
2

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Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

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39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

A = area of the duct
4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number

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Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2
o

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C
5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number
6. Nusselt Number:
Nu = CRe

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m
(Pr)
0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,

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Where, p = perimeter in m
k= 386 w/mk
m= ?(hp/kA)
A = area of fin = (? x D
2

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) /4
L = Length of the fin
Tw ? average temperature
T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL

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Results:
Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

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Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.

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40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Extended Surface
2. What is meant by convective mass transfer?

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3. State the applications of fins.
4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer
6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?

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8. Define ? Conduction
9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?
11. Define ? Convection
12. What is meant by transient heat conduction?

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13. What is meant by radiation?
14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

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41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.8

DETERMINATION OF STEFAN ? BOLTZMANN

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CONSTANT

Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:

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(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Geyser water
Theory:

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The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a

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hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.

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Specifications:
1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm

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5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0

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C
= (or) 0.1 Kcal / kg
0
C
9. No. of thermocouples mounted on B = 4 Nos.

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10. No. of thermocouples mounted on D = 1 No.

42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

11. Temperature indicator digital 0.1

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0
C L.C 0 - 200
0
C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.

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12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.

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Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4
? Td
4

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)
Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

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Schematic view of the test set-up:

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Heater

43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:
Proc
edur
e:
1. H

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eat the
water
in the
tank by
the immersion heater up to a temperature of about 90

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0
C.
2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling

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the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

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Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m
2
k

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4
.

Outcome:

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From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.
.Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

Sl. No.
Hemisphere Temperature(
0

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C) Avg. Temp.
of the
Hemisphere
(Th)
T4

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Steady
Temp. of
Disc
T0 (Td)
Time

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(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?

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3. State Planck?s distribution law.
4. Define ? Biot Number
5. State Wien?s displacement law.
6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.

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8. What are the various types of convection?
9. Define ? Condensation
10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?

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13. State Krichoff's law or radiation
14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

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45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.9

DETERMINATION OF EMISSIVITY OF A GREY

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SURFACE

Aim:
To measure emissivity of the test plate surface at various temperature
Apparatus required:

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(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with

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heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be

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determined.
Specifications:
1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)

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4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V

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8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300
0
C.

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.

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4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.
Tabulation:
Sl.

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No
Voltage

Current

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Black body
temp(
0
C)
Avg.

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temp.

Polished body
temp (
0

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C)
Avg.
temp.

Enclosure

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Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts
4
? Ta

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4
) A
Eb ? E = (W1 ? W2) / ? (Ts
4
? Ta

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4
) A
E = Eb ? {(W1 ? W2) / ? (Ts
4
? Ta

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4
) A}
Where,
W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W

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A = area of plates = 2 (?/4) xd
2
m
2

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T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)
Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

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47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

? = Stefan boltzman constant = 5.67 x 10
-8

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W/m
2
K
4

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Schematic view of the test set-up:


Procedure:

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1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by
the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state

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condition.

Results:
The emissivity of the test plate surface is found to be _____________.
Outcome:

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From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Emissivity
2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?
4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?

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6. What is meant by shape factor?
7. Define ? Radiation
8. What is meant by monochromatic emissive power?
9. Define ? Emissive Power
10. What is meant by absorptivity?

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11. Define ? Black Body
12. What is meant by transmissivity?
13. State Plank's distribution law
14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.10

EFFECTIVENESS OF PARALLEL / COUNTER
FLOW HEAT EXCHANGE

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Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:
(i) Experimental Setup
(ii) Stop watch

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(iii) Thermometer
Theory:
Heat exchangers are classified in three categories:
1. Transfer type
2. Storage type

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3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.
The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.

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ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water
which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by

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means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:
1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm

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3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50
0
C - 2 Nos.

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6. Thermometers (for hot water) = 0 ? 100
0
C - 2 Nos.
7. Measuring flask = 0 ? 1000 CC

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50 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

8. Geyser: single phase type to obtain hot water supply
9. Thermo Cole insulation for outer pipe.
Precautions:

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Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Tabulations:
Sl.
No.

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Flow Hot Fluid (
0
C) Cold Fluid (
0
C)

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Time for
collection of
hot fluid
Kg/sec
Time for

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collection
of cold fluid
Kg/sec
1 Parallel flow
Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)
1. Area of the pipe A = ? (D ? d) L
Where, D = inlet diameter of the outer tube

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d = outlet diameter of the inner tube
L = Length of the tube

2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

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51 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Where, m = mass flow rate Kg/ sec.
m = ?v/t, ? = density of water and t = time taken for hot water
Cp = Specific heat of capacity 4.187 kJ/kg -K

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Thi = Temperature of hot water inlet
Tho = Temperature of hot water outlet

3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W
Where, m = mass flow rate

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Cp = Specific heat of capacity
Tco = Temperature of cold water inlet
Tci = Temperature of cold water outlet
4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W
Where, Q? = (Qa + Qc) / 2

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5. Logarithmic mean temperature difference( L M T D)
?Tm = (?Ti - ?To) / In (?Ti/?To)
Where, ?To = Tho ? Tco
?Ti = Thi ? Tci
6. Over all heat transfer coefficient

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h = Q?/?Tm A W/m
2
K
where Q? = (Qa + Qc) / 2

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Procedure:
1. Place the thermometers in position and note down their readings when they are at room temperature and
no water is flowing at either side. This is required to correct the temperature.
2. Start the flow on hot water side.
3. Start the flow through annulus and run the exchanger as parallel flow unit.

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4. Put ON the geyser.
5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.
6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.
7. Keeping the flow rates same, wait till the steady state conditions are reached.
8. Record the temperatures on hot water and cold water side and also the flow rates accurately.

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9. Repeat the experiment with a counter flow under identical flow conditions.
10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Result:
1. The values of effectiveness of heat exchanger were found as
(i) Parallel flow = ________.
(ii) Counter flow = _________.

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2. Over all heat exchanger (heat transfer coefficient)
(i) Parallel flow = ________.
(ii) Counter flow = _________.

Outcome:

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From this experiment, determining the values of effectiveness of parallel and counter flow
heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat
exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Heat Exchanger
2. What are the types of heat exchangers?

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3. What is meant by indirect contact heat exchanger?
4. Write about the merits of drop wise condensation.
5. What is meant by film wise and drop wise condensation?
6. What is meant by effectiveness?
7. Define ? Direct Heat Exchanger

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8. What is meant by fouling factor?
9. Distinguish between regenerator and recuperates.
10. What is meant by parallel flow heat exchanger?
11. What is meant by counter flow heat exchanger?
12. What is meant by cross flow heat exchanger?

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13. What is meant by shell and tube heat exchanger?
Viva ? voce

53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.11

DETERMINATION OF COP OF A REFRIGERATION
SYSTEM

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Aim:
To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration
system
Apparatus required:
(i) Thermometer

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(ii) Electric Heater
(iii) Stop watch
(iv) Experimental setup
Description:
1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a

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reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.
2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated
wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a
low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the
temperature of chilled water. The above unit is located on the trolley behind front panel.

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3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic
expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum
strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure
gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high
pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy

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meter to measure the power consumed either by hater or by compressor.

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54 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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A. A compressor condenser unit placed inside trolley and fitted with
1. R-134a reciprocating compressor
2. Condenser
3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan
4. A receiver with angle check valve

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B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity
placed inside a well insulated wooden box and provided with
5. Evaporator coil
6. Stirrer
7. Electric heater 230 V, A.C.

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8. The sensing bulb of low temperature thermostat.
9. A high temperature thermostat.
10. A Thermometer to measure the chilled water temperature
C. The front panel on which are mounted the following
11. Capillary expansion tube with isolating valve.

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12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator
and isolating valve
13. Drier cum strainer and sight glass
14. Thermostat at inlet and outlet of both evaporator and condenser
15. Pressure gauge at inlet and outlet of evaporator and condenser

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16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out
17. Heat power regulator switch and regulator
18. Energy meter to measure the power consumed either by hater or by compressor.

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55 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.

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2. The heater regulator should be switched off whenever not in use. Heating water beyond 40
0
C may lead to
permanent damage of the entire system. A high temperature cut off thermostat is provided in the water
chiller, to cut off the heater beyond 30

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0
C.Check the setting of the same before operation.
3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.
4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.
5. The solenoid thermostat is adjusted to cut at 15

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0
C and cut in at 10
0
C of the chilled water. Do not alter the
same.

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6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.
7. The space near the condenser should permit good ventilation to aid proper fan performance.
8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked
in
0

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F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,
calibrated in SI units, are not available.)
9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to
obtain the pressure in MN/m
2

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.e.g. P = x psig
= (x + 14.7) psia
= (x + 14.7) / 145 MN/m
2
(MPa)

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10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.
Formulae used:
Let, State 1 indicates the entry of compressor.
State 2 indicates the exit of compressor.
State 3 indicates the exit from condenser.

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State 4 indicates the entry to evaporator
P = Pressure (bar)
T = Temperature (
0
C)

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H = Specific enthalpy (kJ/kg)
v = Specific Volume (m
3
/Kg)
n = Number of revolutions of energy meter disc.

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t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)
t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)
K = Energy meter constant = 3200 lmp / kWh
N = Speed of compressor = 2840 rpm
h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

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56 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2
h3 = Specific enthalpy at Pc and T3 (kJ/kg)

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h4 = h3
Stroke volume of compressor = (?/ 4) d
2
l = 12.58 x 10
-6

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m
3

1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar
2. Average condenser pressure, Pc = (P2 + P3) / 2 bar

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3. Heater input, Qe = (n / t1) x (3600 / k) kW
4. Compressor input, W = (n / t2) x (3600 / k) kW
5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1
6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)
7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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57 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

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Sl.
No.

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Initial
Temp.
of water

Final

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Temp.
of water
Duration
of exp.

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Delivery
pressure

Delivery
Temp.

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Condense
Outlet
Pressure

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Condense
Outlet
Temp.

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Pressure
after
throttling

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Temp.
After

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Throttli
ng


Suction

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pressur
e
Suction
Temp.

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Time for
10 rev. of

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compress
or energy
meter

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Height
of water
in the
vessel

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58 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
Load Test with Capillary tube as expansion device:
1. Fill the chilled water calorimeter with pure water so that the evaporative coils are

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fully immersed.
2. Select the capillary tube line by opening the shut-off valve on this line and closing
the one on the thermostatic expansion valve line. The solenoid switch is switched OFF.
3. Start the compressor and run for some time so that the chilled water temperature
is lowered to the given test temperature.

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4. Switch on the heater and slowly increase the power.
5. Allow The temperature in water calorimeter to reach the equilibrium
temperature.
6. Connect energy meter to motor and heater by the selector switch one after another
and note down the time taken for 10 pulses of the energy meter disc.

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7. Note down the pressure and temperature readings at locations 1,2,3 & 4 as
mentioned.
8. Switch OFF the heater and the mains.
Result:
The load test on a refrigeration test rig was conducted and the results are as follows.

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1. Actual C.O.P. of the system =____________.
2. Rhetorical C.O.P. of the system = ___________.
3. Volumetric Efficiency = ___________.

Outcome:

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From this experiment, conducting the load test on a refrigeration test rig and finding out the
volumetric efficiency and co-efficient of performance for any type of refrigerant is learnt and this experiment
could be used in the areas such as Refrigerator and Air Conditioning.
Applications:
Refrigerator, Air Conditioning.

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59 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? COP
2. Which thermodynamic cycle is used in air conditioning of airplanes using air as refrigerant?

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3. Define ? Ton of Refrigeration
4. What is meant by refrigeration?
5. What is meant by air conditioning?
6. What are the four important properties of a good refrigerant?
7. How does the actual vapour compression cycle differ from that of the ideal cycle?

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8. Name any four commonly used refrigerants.
9. What are the expansion devices used in a vapour compression plant?
10. Why throttle valve is used in place of expansion cylinder for vapour compression refrigerant machine?
11. What are the merits of air refrigeration system?
12. What are the demerits of air refrigeration system?

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13. Define ? Refrigerant
14. What is net refrigerating effect of the refrigerant?
15. What are the methods to obtain sub cooling of refrigerant?

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Viva ? voce

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60 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.12 EXPERIMENTS ON PSYCHROMETRIC PROCESS

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Aim:
To conduct an experiment on psychrometric processes with air conditioning system
Apparatus required:
(i) Thermometer
(ii) Electric Heater

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(iii) Stop watch
(iv) Digital anemometer
(v) Experimental setup
Description:
The test rig consist of

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1. An air duct support of stand
2. A blower to set up air flow through the duct along with a speed control to vary the
velocity of air.
3. A heater to rise the air temperature with regulator and energy meter.
4. Water spray, collecting tray, reservoir with gauge pump.

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5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.
(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after cooling coil).
6. The test rig consist of compressor, condenser unit placed inside trolley and fitted
with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for
condenser and (iv) Liquid receiver.

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7. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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61 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Observation Table: I

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Precautions:
1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence
avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kw only for the motor
circuit.

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2. Natural air currents in the room if in the direction of air duct may defect the experimental results and
hence the duct should be placed such that no wind from doors, windows, fan and cooling air from
other test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan
and should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase
beyond 240 psi.

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3. Never exceed dry bulb temperatures of 40
0
C after the heater (station 2) otherwise the air duct may be
damaged.
4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may

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exceed its maximum of 32
0
C and calibration may be affected.
5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not
running this will lead to rise in temperature at the heater and may damage the heater and the air duct.

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6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their
duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.
7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer
is placed inside the reservoir at the top. This may have to the cleaned when necessary.
8. Do not open the gate valve fully otherwise water may be splashed outside and the waster

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measurement may be in error.
S.
N
o
Inlet temp

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Outlet
temp
Pressu
re
P1

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Tem
p.
T1
Pressu
re

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P2
Temp.
T2
Pressu
re

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P3

Tem
p.
T3

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Pressu
re
P4

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Temp.
T4
Energy

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for 10
revolutio
ns
Twet Tdry Twet Tdry Lb/in
o

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C Lb/in
o
C Lb/in
o
C Lb/in

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o
C


62 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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9. If the low pressure cut out comes in to action, it means that the Freon charge is insufficient and may
have to be filled up. The suction pressure should never go below 2 psi as otherwise the compressor
seals will be damaged and air and moisture may enter the system.
10. The refrigerant strainer placed on the front panel should always be warm. If it cools and moisture

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condenser on it, then the strainer might have to be charged by an experienced refrigeration
mechanics.
11. The refrigerating system can work continuously for 2 hours, however if the room temperature is above
25
0

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C the condenser may be heated up and the delivery pressure may rise. Do not exceed 240 psi.
Pour one or two glasses of drinking water over the fins of the condenser in order to reduce the
delivery pressure.
12. After some months of operation the compressor may have to be topped up with oil and some quantity
of Freon-22 may have to be charged by an experienced mechanics.

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13. See that distilled water is filled up in the plastic dishes provided under the wet bulb thermometers and
that the wicks are in tact otherwise erroneous readings may be obtained. These thermometers will
show correct readings only when the fan is in operation.
14. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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Formulae used:
1. Corresponding to the dry and wet bulb temperature at all the stations obtain the specific enthalpy and
specific humidity values from psychrometric chart.
i.e., h1 and w1 at tb1 and tw1 and so on.

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2. Air flow rate, ma = (A x V) / v4 Kg / sec
Where, A = Area of duct at outlet in m
2
(0.46 m x 0.086 m)
V = Air velocity ( m / sec)

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V4 = Specific volume of moist air at station 4 using psychometric chart m
3
/Kg
3. Moisture added from psychrometric chart, mw1 = ma (w3-w2) Kg / sec.
Where, w3 = Specific humidity at station 3

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w2 = Specific humidity at station 2
4. Cooling effect produced on air, Qe = ma (h3 ? h4) kW.
Where, h3 = Specific enthalpy at state 3 kJ/kg
h4 = Specific enthalpy at state 4 kJ/kg
5. Moisture condensed, mcl = ma (w3 ? w4) kg/sec

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Where, w3 = Specific humidity at station 3
w4 = Specific humidity at station 4

63 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Fill water in the wet bulb temperature probe trays.
2. Start the main.
3. Start the blower and run it the required speed by keeping the speed regulator at
position.

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4. Start the spray pump and open the gate valve suitably.
5. Start the heater.
6. Select the expansion device (Capillary tube / Thermostatic expansion valve)
7. Start the cooling compressor.
8. Wait for some time till thermometers shown practically constant readings and note down the

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following readings:
(i) Dry bulb temperatures tdb1, tdb2, tdb3, tdb4.
(ii) Wet bulb temperatures twb1, twb2, twb3, twb4.
(iii) Spray water temperature, ts
(iv) Surface temperature of cooler, tm ( at control panel)

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(v) Pressure gauge reading, pd ( at control panel)
(vi) Compound gauge reading, Ps ( at control panel)
(vii) Level reduction?l? in spray reservoir (mm) during 5 min.
(viii) Amount of condensate collected ?lc?, in a measuring jar at cooler tray during a
run of 5 minutes at constant conditions.

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(ix) Time in second ?SH? for 10 pulses of the energy meter disc connected to the
heater.
(x) Time in seconds Sc for 10 pulses of the energy meter disc connected to cooler
compressor.
Result:

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Experiment on psychrometric processes with air conditioning system was drawn
Outcome:
From this experiment, conducting the test on psychrometric processes with air
conditioning system is learnt and this experiment could be used in all types of air conditioning systems.

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Applications:
Air Conditioning.

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64 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is the commonly used unit of refrigeration?

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2. Distinguish between summer air conditioning and winter air conditioning.
3. Define ? RSHF Line
4. Define ? By Pass Factor of a Heating Coil
5. What is the effect of sub cooling a refrigerant in a vapour compression cycle?
6. What is the function of analyzer and rectifier in an absorption system?

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7. What is the purpose of generator assembly in vapour absorption refrigeration system?
8. State the substance used in the Lithium Bromide system and their functions.
9. Differentiate wet compression from dry compression.
10. Define ? Apparatus Dew Point
11. What is meant by dew point temperature?

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12. Define ? Wet Bulb Temperature
13. Define ? Degree of Saturation
14. What is meant by specific humidity?
15. Define ? Relative Humidity

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Viva ? voce

65 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.13

PERFORMANCE TEST ON A RECIPROCATING
AIR COMPRESSOR

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Aim:
To conduct a load test on the 2 - stage reciprocating air compressor to determine the isothermal and
volumetric Efficiencies at various delivery pressures

Apparatus required:

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* Air compressor with accessories.
* Stop watch.
Description:
Two stage air compressors is a reciprocating type driven by a prime mover. The test rig consist of a base on
which the tank is mounted. The outlet of the compressor is connected to the receiver. The suction is

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connected to air tank with a calibrated orifice plate through a water manometer. The input to the motor is
recorded by an energy meter. The temperature and pressure of the air compressed is indicated by a
thermometer and pressure gauge.
Specifications:
1. Air compressor:

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* LP Bore, DLP = 63.0 mm.
* HP Bore, DHP = 79.0 mm.
* Stroke, L = 80.0 mm.
* Speed, N = 1440 rpm (5 HP)
* Effective radius = 0.193 m

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2. Air receiver capacity = 0.33 m3
3. Orifice, diameter, d0 = 12 mm
4. Orifice area,. A0 : ?d0
2
/ 4 = ----------- m

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2

5. Coefficient of discharge C d. = 0.6
6. Energy-meter constant = 200 rev / kWh

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66 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

Observation Table: II

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Sl.
No.
Actual
Discharge
Va

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Theoritical
Discharge
Vt
Volumetric
Efficiency

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?
Power
Input

Output

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Power

Overall
Efficiency
?0

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Isothermal
Workdone
IwD
Polytropic
Workdone

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PwD
Isothermal
Efficiency
?iso
m

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3
/sec m
3
/sec % kW kW % J/Kg J/Kg %

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Sl.
No.
Pressure
p

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Manometer
h1
Manometer
h2
Time for 5 revolutions Energy meter Speed of the compressor Temperature

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T1
Temperature
T1
Kg/cm
2

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Cm cm sec rpm
o
C
o
C

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67 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Check whether manometer is filled with water up to the required level.
2. The maximum pressure in the receiver tank should not exceed 12 kg / cm
2

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Procedure:
1. Ensure that gauge pressure in the tank is zero.
2. Start the compressor. Read the receiver pressure gauge for a particular pressure.
3. Maintain the pressure constant by adjusting the outlet valve.
4. Note down the manometer reading and time taken for 3 revolution of the energy

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Formulae used:
1. Density of air at RTP:
? RTP = ? NTP X 273 Kg/ m
3

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(273 + Room Temp)
Where density of air at NTP = 1.293 Kg/ m
3
.

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2. Air head causing flow:
ha RTP = (h1 - h2) x ? water m
?a RTP
Where,
(h1- h2) = Difference in manometer liquid, in m.

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3. Actual volume at RTP:
Va RTP = C.d x Ao x ? 2 g ha RTP
Where,
C d= Coefficient of discharge = 0.6.

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A o = Area of orifice = ?(d0)
2
m
2
.

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4
Diameter of orifice d o = 0.01 m.
4. Actual volume at NTP:
Va NTP = VaRTP x T NTP
T RTP

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Where,
T NTP = Normal temp - 273
o
k
T RTP = Room temp -

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o
c (273 + TROOM )

68 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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5. Theoretical Volume of air: (at intake conditions)
V T = ?D
2
x L x Nc m
3

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/ sec.
4 x 60
D = LP Bore diameter = 88.5 mm.
L = Stroke length = 88.9 mm.
Nc = Compressor speed rpm.

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6. Volumetric Efficiency:(for LP stage)
?vol = Va NTP x 100%
Vt
7. Shaft Input through Energy meter:

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= 1 x n x ?t x ?m x 3600 kw.
( Ec x t )
Where,
Ec = Energy meter constant = 200 rev / kWh
?t = Efficiency for transmission = 0.95.

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? m = Efficiency for motor = 0.90.
t = Time for 'n' revolution of energy meter disc.
n = no. of rev. of Energy meter disc.

8. Isothermal power:

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= Pa x Va RTP x log e (R) W
1000
Pa = Atmospheric pressure in N/ m
2
= 1.01325 x 10

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5
N / m
2
.
R = (Pressure gauge reading + atmospheric pressure)

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atmospheric pressure.
9. Isothermal efficiency:
? ISO = Isothermal power x 100%
Shaft input

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Result:
The values of isothermal and volumetric efficiency at various delivery pressures have been studied &
graph between Pressure Vs Volumetric efficiency and Pressure Vs Isothermal efficiency are drawn.

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69 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Outcome:
From this experiment, conducting the load test on two stage reciprocating air compressor for
determining the isothermal and volumetric Efficiencies at various delivery pressures is understood and this

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experiment could be used in the areas such as Refrigerator, Air Conditioning, IC engines, etc.

Applications:
Refrigerator, Air Conditioning, IC engines.

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1. How are air compressors classified?
2. Define ? Isothermal Efficiency of Air Compressor
3. What is meant by FAD (Free Air Delivery)?
4. What is meant by perfect inter-cooling?

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5. Define ? Clearance Ratio of an Air Compressor
6. List out the applications of compressed air.
7. What are the types of air compressors?
8. What is meant by single acting compressor?
9. What is meant by double acting compressor?

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10. What is meant by single stage compressor?
11. What is meant by multi stage compressor?
12. Indicate the applications of reciprocating compressors in industry>
13. Define ? Mechanical Efficiency
14. What is meant by compression ratio?

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15. What are the factors that affect the volumetric efficiency of a reciprocating compressor?

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Viva ? voce

70 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.14

PERFORMANCE TEST IN A HC REFRIGERATION
SYSTEM

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Aim:

To conduct the performance test on Vapour Compression Refrigeration System and to determine the

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Coefficient of Performance using solenoid valve by throttling method

Description:

In this system the working fluid is a HC out of a refrigeration system. The HC compression system is most

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important system from the view point of commercial and domestic utility. The HC refrigerant at low temp and
pressure enters the reciprocating compressor, where it is compressed isentropically and subsequently its temp
and pressure increases considerably. This HC after leaving the compressor enters the condenser where it is
cooled into low temperature. Then it is sucked by reciprocating compressor and is thus repeated.
Formula used:

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Actual COP = refrigerant effect
I/p energy to compressor
Refrigerant effect = mxCpx ? T
t

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m - mass of water (kg)
Cp - Sp. Heat of water (4.2 kJ/kg K)
?T ? decrease in temp (Ti-Ts)
t - timetaken duration of expt (sec)

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Energy input =n x 3600 /k x t
n ? number of revolutions in energy meter
t ? time taken of ?n? revolutions
k ? energy meter constant (3200)

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71 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:

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Pressure of the refrigerant (Mpa) Temperature Time for n?
rev of
energy
meter in
sec

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P1 P2 P3 P4 Circulating fluid
temp
Refrigerant temp

Ti Tf T1 T2 T3 T4

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72 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Model calculation:

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Actual COP = refrigerant effect
I/p energy to compressor

Refrigerant effect = mxCpx ? T
t

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m - mass of water (kg)
Cp - Sp. Heat of water (4.2 kJ/kg K)
?T ? decrease in temp (Ti-Ts)
t - time taken duration of experiment (sec)
Refrigerating effect = 8x4.2x (27-6)/1200=0.588 kw

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Energy input = n x 3600
n ? Number of revolutions in energy meter
t ? Time taken of ?n? revolutions
k ? Energy meter constant

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=3 x 3600/(1200 x 54)
=0.166 kW
Actual COP = refrigerant effect
I/p energy to compressor
= 0.588/0.166

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=3.526
Result:

The experiment was conducted successfully and coefficient of performance was found out is _______.

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Outcome:
From this experiment, conducting the performance test on Vapour Compression Refrigeration
System and to determine the Coefficient of Performance using solenoid valve by throttling method is
understood and this experiment could be used in the areas such as Refrigerator and Air Conditioning systems.
Applications:

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Refrigerator, Air Conditioning.

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73 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the difference between air conditioning and refrigeration?
2. Write any three important properties of a good refrigerant.
3. What is the function of analyzer and rectifier in an absorption system?
4. How does humidity affect human comfort?

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5. What is the commonly used unit of refrigeration?
6. Distinguish between summer air conditioning and winter air conditioning.
7. Define ? RSHF Line
8. Define ? By Pass Factor of a Heating Coil
9. What is the effect of sub cooling a refrigerant in a vapour compression cycle?

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10. What is the function of analyzer and rectifier in an absorption system?
11. What is the purpose of generator assembly in vapour absorption refrigeration system?
12. State the substance used in the Lithium Bromide system and their functions.
13. Differentiate wet compression from dry compression.
14. Define ? Apparatus Dew Point

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15. What is meant by dew point temperature?
16. Define ? Wet Bulb Temperature
17. Define ? Degree of Saturation
18. What is meant by specific humidity?
19. Define ? Relative Humidity

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20. What is meant by dew point temperature?

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Viva ? voce

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74 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.15

PERFORMANCE TEST IN A FLUIDIZED BED

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COOLING SYSTEM

Aim:
To determine the performance test on cooling tower
Introduction:

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The cooling tower is one of the most important device in chemical industries for example when the hot
water come from heat exchanger we use the cooling tower to cool it The purpose of cooling tower is to cool
relatively warm water by contacting with unsaturated air. The evaporation of water mainly provides cooling. In
typical water cooling water tower warm water flows countercurrent to an airstream. Typically, the warm water
enters the top of the packed tower and cascades down through the packing , leaving at the bottom Air enters

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at the bottom of the tower and flows upward through the descending water . The tower packing often consist of
slats of plastic or of packed bed. The water is distributed by troughs and overflows to cascade over slat
gratings or packing that provides large interfacial areas of contact between the water and air in the form of
droplets and films of water. The flow of air upward through the tower can be induced by the buoyancy of the
warm air in the tower (natural draft) or by the action of a fan . The water cannot be cooled below the wet bulb

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temperature. The driving force for the evaporation of water is approximately the vapour pressure of the water
less the vapour pressure it would have at the wet bulb temperature
Procedure:
1. Introduce water and record its flow rate.
2. Switch ON the heaters on so that water is heated to the required temperature.

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3. Introduce air and record its flow rate.
4. Wait for steady state then record steady state dry and wet bulb temperature of air at the entrance and
exit.
5. Record the inlet and outlet temperature and flow rate of water also record temperature at different
stages.

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Tabulation:

Sl.No. T1 (
0
c) T2 (

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0
c) T3 (
0
c) Efficiency

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T1 = room temperature

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75 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

T2 = water inlet
T3 = water outlet

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Efficiency of cooling tower

ECT = T3/T2/*100

Model calculation:

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Efficiency of cooling tower = water outlet
--------------- *100
Water inlet

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= 36/40 *100

= 90
Result:
The performance test in cooling tower is determined as ______%.

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Outcome:
From this experiment, conducting the performance test on cooling tower is understood and this
experiment could be used in various power plants where cooling tower is used.
Applications:
Power Plant Cooling Tower, Cooling Tower.

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1. What are functions of a draught system?
2. What are the advantages of burning coal in pulverized form?
3. What are the functions of cooling tower?

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4. What are the different types of draught system?
5. What are the methods used for handling of coal?
6. What is meant by fluidized bed combustion?
7. What is the use of fluidized bed boiler?
8. What are the types of fluidized bed boiler?

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9. State the purpose of condenser in fluidized bed boiler.
10. What is meant by pulveriser and why it is used?
11. State the disadvantages of pulverized coal firing.
12. Distinguish between fouling and slagging.
Viva ? voce

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________

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Section : _______________________________________

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LABORATORY MANUAL
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is committed to provide highly disciplined, conscientious and

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enterprising professionals conforming to global standards through value based quality education and training.



? To provide competent technical manpower capable of meeting requirements of the industry

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? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
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professionally sound mechanical engineers of excellent caliber



To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on

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experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould

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them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth

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To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up

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their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME OUTCOMES (POs)

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On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications

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4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability

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8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills

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11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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ME6512 ? THERMAL ENGINEERING LABORATORY ? II



? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the

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performance of refrigeration cycle / components

LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus

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2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder

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7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

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REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System

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15. Performance test in a fluidized Bed Cooling Tower



1. Able to find out the thermal conductivity of various materials.

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2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials

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6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.

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11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures

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14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
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CONTENTS


Sl.No.
Name of the experiment

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Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe

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apparatus
11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder

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15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS

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6
Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39

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9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58

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13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS

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16 Air conditioning test rig 75
PROJECT WORK 81

8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

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Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup

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(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to

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prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater

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assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved

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aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK

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3. Area, A = ( ?/4) d
2
(10 + x)

cm

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2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.

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2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there

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is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

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Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm

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4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40

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0
C ? 100
0
C
9. Maximum temperature of the hot plate = 170

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0
C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)

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13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)

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18. Temperature indicator = 0 ? 200
0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm

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21. Specimen used = Press wood

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Tabulation:

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Sl. No. Voltmeter
V
Ammeter
A
Main heater (

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0
C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water

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is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from

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thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably

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steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:

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Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded

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hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.

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6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer

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11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?

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16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

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Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup

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(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter
Theory:

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The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in

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the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:
1. Diameter of the heater Rod = 20 mm.

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2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).

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2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by

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Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging

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material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.
No.
Voltage

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(V)
Current
(A)
Heater Temperature
(

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0
C)
Asbestos Temperature
(
0

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C)
Saw dust
Temperature (
0
C)

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T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.

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4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.

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7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2

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-K

Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC

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engines, heat exchangers, etc. where heat transfer is to be found.

Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?

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4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?

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9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?

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14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis

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19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

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Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:
(i) Experimental setup

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(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at

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the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

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When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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Schematic view of the test set-up:
mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm

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3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0

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C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V

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9. Heater = Cartridge type (400 W)

Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (

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0
c)

V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:

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1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2
K

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As = Area of heat transfer surface = ? x d x l m
2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0

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C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0
C) ?

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2. hL / k = A { g L
3
?T Cp ?/2v
2
}

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n

Where, hL / k are called Nusselt Number.
L
3

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g?T / v
2
is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.

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Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid

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? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0

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K
-1

Where Tf = (Ts + Ta )/ 2

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For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25
for 10

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4
< Gr.Pr.<10
8

hL / k = 0.13 (Gr.Pr)

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1/3
for 10
8
< Gr.Pr.<10
12

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Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

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Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2

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K
Experimental = ______________ W/ m
2
K

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Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?

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3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?

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8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer

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13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.

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18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No. 4

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

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Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:

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(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

Theory:

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Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat

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supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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Tabulations:

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Sl. No. Voltage Current Temperature in (
0
C)
Manometer

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reading of water
in h in meter

(V) (A)
T1

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T2

T3

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T4

T5

T6

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h1
cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm

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3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300

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0
C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A

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10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.

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4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:

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1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady

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state is reached.
4. Note down the heater input.

26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)

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?T = Temperature rise in air (
o
C)
= T6 ? T1.
2. m = Q?

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Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m

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3
/hr
3. ha = qa /A(Ts- Ta) W / m
2
K

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qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

Ta = Average temperature of air = (T1 + T6)/2

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o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C

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Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

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?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s

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2

using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number

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Where, V = velocity of air = Q/[(? x Di
2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2

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o
C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K

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Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

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Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

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k = Thermal conductivity of fluid W/m
2
K
Nu = 0.023 (Re)
0.8

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(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

Results:

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Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m
2
K

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htheoritical = -------------- W/m
2
K

Outcome:

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From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.

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6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?

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11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall

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Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The

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temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus

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uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.

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Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.

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Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.

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4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from

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the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate

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Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter
reading

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(V)
Ammeter
reading
(A)
T1

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(
0
C)
T2
(

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0
C)
T3
(
0

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C)
T4
(
0
C)

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T5
(
0
C)
T6

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(
0
C)
T7
(

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0
C)
T8
(
0

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C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:
The rate of heat transfer through different materials are found to be

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a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

Outcome:

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From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.



32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?

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3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.

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7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?

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12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

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Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between

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the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

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Procedure:

1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.

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3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter
reading( V)
Ammeter

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reading (A)
T1
(
0
C)

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T2
(
0
C)
T3

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(
0
C)
T4
(

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0
C)

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Calculations:

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The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Fig. 1 Apparatus of thermal conductivity of insulating powder

[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

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Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

Outcome:

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From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?

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6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?

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11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection

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16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.7

HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

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Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer
Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of

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the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:

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Forced convection:
Sl.
No.
V I

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Fin Temperatures (
0
C)
Ambient Temp
(

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0
C)
Manometer
Reading
(V)

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(A)

T1 T2 T3 T4 T5 T6 T7 T8
h1

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cm
h2
cm

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Specifications:
1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm

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5. Diameter of the delivery pipe (O.D) = 46 mm

Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64

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8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0

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C
12. Temperature indicator = 0 ? 300
0
C
(With compensation of ambient temperature up-to 50

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0
C)
13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V

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T7 T6 T5 T4 T3 T2 T1
T8
Brass Pin Fin
Heater

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38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.

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7. Do not exceed 200 W.
Procedure:
Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.

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2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.

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Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D

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2
) /4}?2gha m
3
/s.
Where, ha (head of air) = (?w / ?a) x H m

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H = Difference of water level in manometer m
?w Density of water = 1000 kg/m
3

?a = Density of air = 1.165 kg/m

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3
g = acceleration due to gravity = 9.81 m/s
2

Cd = Coefficient of discharge = 0.64

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D = diameter of the orifice
3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

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A = area of the duct
4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?

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D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2
o
C

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5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number
6. Nusselt Number:
Nu = CRe
m

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(Pr)
0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m

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k= 386 w/mk
m= ?(hp/kA)
A = area of fin = (? x D
2
) /4

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L = Length of the fin
Tw ? average temperature
T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:

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Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

Outcome:

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From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.

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40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.

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4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer
6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction

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9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?
11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?

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14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.8

DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

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Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer

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(ii) Electric Heater
(iii) Stop watch
(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The

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outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A

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chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:

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1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve

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6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C

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= (or) 0.1 Kcal / kg
0
C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

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42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

11. Temperature indicator digital 0.1
0

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C L.C 0 - 200
0
C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW

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13. Tank for hot water
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:

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Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4
? Td
4
)

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Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

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Schematic view of the test set-up:

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Heater

43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulations:

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Proc
edur
e:
1. H
eat the

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water
in the
tank by
the immersion heater up to a temperature of about 90
0

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C.
2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant

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cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

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Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m
2
k
4

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.

Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus

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is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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Sl. No.
Hemisphere Temperature(
0
C) Avg. Temp.

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of the
Hemisphere
(Th)
T4
Steady

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Temp. of
Disc
T0 (Td)
Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?
3. State Planck?s distribution law.

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4. Define ? Biot Number
5. State Wien?s displacement law.
6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.
8. What are the various types of convection?

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9. Define ? Condensation
10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?
13. State Krichoff's law or radiation

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14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.9

DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

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Aim:
To measure emissivity of the test plate surface at various temperature
Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer
Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide

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undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.

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Specifications:
1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.

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Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.

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9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300
0
C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.

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5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.
Tabulation:
Sl.
No

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Voltage

Current

Black body

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temp(
0
C)
Avg.
temp.

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Polished body
temp (
0
C)

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Avg.
temp.

Enclosure
Temp.

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(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:

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Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts
4
? Ta
4

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) A
Eb ? E = (W1 ? W2) / ? (Ts
4
? Ta
4

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) A
E = Eb ? {(W1 ? W2) / ? (Ts
4
? Ta
4

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) A}
Where,
W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd

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2
m
2

T = Temperature of black plate, k = (Ts + Ta) / 2

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Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)
Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

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47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

? = Stefan boltzman constant = 5.67 x 10
-8
W/m

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2
K
4

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Schematic view of the test set-up:


Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.

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And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by
the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

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Results:
The emissivity of the test plate surface is found to be _____________.
Outcome:
From this experiment, finding the emissivity of the test plate surface at various

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temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Emissivity

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2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?
4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?
6. What is meant by shape factor?

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7. Define ? Radiation
8. What is meant by monochromatic emissive power?
9. Define ? Emissive Power
10. What is meant by absorptivity?
11. Define ? Black Body

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12. What is meant by transmissivity?
13. State Plank's distribution law
14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.10

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EFFECTIVENESS OF PARALLEL / COUNTER
FLOW HEAT EXCHANGE

Aim:

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To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:
(i) Experimental Setup
(ii) Stop watch
(iii) Thermometer

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Theory:
Heat exchangers are classified in three categories:
1. Transfer type
2. Storage type
3. Direct contact type.

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A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.
The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.

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iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water
which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run

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as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:
1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm

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4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50
0
C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100

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0
C - 2 Nos.
7. Measuring flask = 0 ? 1000 CC

50 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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8. Geyser: single phase type to obtain hot water supply
9. Thermo Cole insulation for outer pipe.
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically

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there is no temperature rise in the circuiting fluid.
Tabulations:
Sl.
No.
Flow Hot Fluid (

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0
C) Cold Fluid (
0
C)
Time for

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collection of
hot fluid
Kg/sec
Time for
collection

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of cold fluid
Kg/sec
1 Parallel flow
Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)
1. Area of the pipe A = ? (D ? d) L
Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube

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L = Length of the tube

2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

51 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Where, m = mass flow rate Kg/ sec.
m = ?v/t, ? = density of water and t = time taken for hot water
Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet

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Tho = Temperature of hot water outlet

3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W
Where, m = mass flow rate
Cp = Specific heat of capacity

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Tco = Temperature of cold water inlet
Tci = Temperature of cold water outlet
4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W
Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)

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?Tm = (?Ti - ?To) / In (?Ti/?To)
Where, ?To = Tho ? Tco
?Ti = Thi ? Tci
6. Over all heat transfer coefficient
h = Q?/?Tm A W/m

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2
K
where Q? = (Qa + Qc) / 2

Procedure:

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1. Place the thermometers in position and note down their readings when they are at room temperature and
no water is flowing at either side. This is required to correct the temperature.
2. Start the flow on hot water side.
3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.

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5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.
6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.
7. Keeping the flow rates same, wait till the steady state conditions are reached.
8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.

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10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Result:
1. The values of effectiveness of heat exchanger were found as
(i) Parallel flow = ________.
(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)

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(i) Parallel flow = ________.
(ii) Counter flow = _________.

Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow

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heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat
exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Heat Exchanger
2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?

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4. Write about the merits of drop wise condensation.
5. What is meant by film wise and drop wise condensation?
6. What is meant by effectiveness?
7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?

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9. Distinguish between regenerator and recuperates.
10. What is meant by parallel flow heat exchanger?
11. What is meant by counter flow heat exchanger?
12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?

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Viva ? voce

53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.11

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DETERMINATION OF COP OF A REFRIGERATION
SYSTEM

Aim:

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To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration
system
Apparatus required:
(i) Thermometer
(ii) Electric Heater

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(iii) Stop watch
(iv) Experimental setup
Description:
1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a
reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.

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2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated
wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a
low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the
temperature of chilled water. The above unit is located on the trolley behind front panel.
3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic

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expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum
strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure
gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high
pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy
meter to measure the power consumed either by hater or by compressor.

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54 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
A. A compressor condenser unit placed inside trolley and fitted with

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1. R-134a reciprocating compressor
2. Condenser
3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan
4. A receiver with angle check valve
B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity

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placed inside a well insulated wooden box and provided with
5. Evaporator coil
6. Stirrer
7. Electric heater 230 V, A.C.
8. The sensing bulb of low temperature thermostat.

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9. A high temperature thermostat.
10. A Thermometer to measure the chilled water temperature
C. The front panel on which are mounted the following
11. Capillary expansion tube with isolating valve.
12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator

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and isolating valve
13. Drier cum strainer and sight glass
14. Thermostat at inlet and outlet of both evaporator and condenser
15. Pressure gauge at inlet and outlet of evaporator and condenser
16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out

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17. Heat power regulator switch and regulator
18. Energy meter to measure the power consumed either by hater or by compressor.

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55 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.
2. The heater regulator should be switched off whenever not in use. Heating water beyond 40

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0
C may lead to
permanent damage of the entire system. A high temperature cut off thermostat is provided in the water
chiller, to cut off the heater beyond 30
0

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C.Check the setting of the same before operation.
3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.
4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.
5. The solenoid thermostat is adjusted to cut at 15
0

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C and cut in at 10
0
C of the chilled water. Do not alter the
same.
6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.

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7. The space near the condenser should permit good ventilation to aid proper fan performance.
8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked
in
0
F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,

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calibrated in SI units, are not available.)
9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to
obtain the pressure in MN/m
2
.e.g. P = x psig

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= (x + 14.7) psia
= (x + 14.7) / 145 MN/m
2
(MPa)
10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.

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Formulae used:
Let, State 1 indicates the entry of compressor.
State 2 indicates the exit of compressor.
State 3 indicates the exit from condenser.
State 4 indicates the entry to evaporator

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P = Pressure (bar)
T = Temperature (
0
C)
H = Specific enthalpy (kJ/kg)

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v = Specific Volume (m
3
/Kg)
n = Number of revolutions of energy meter disc.
t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)

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t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)
K = Energy meter constant = 3200 lmp / kWh
N = Speed of compressor = 2840 rpm
h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

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56 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2
h3 = Specific enthalpy at Pc and T3 (kJ/kg)
h4 = h3

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Stroke volume of compressor = (?/ 4) d
2
l = 12.58 x 10
-6
m

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3

1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar
2. Average condenser pressure, Pc = (P2 + P3) / 2 bar
3. Heater input, Qe = (n / t1) x (3600 / k) kW

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4. Compressor input, W = (n / t2) x (3600 / k) kW
5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1
6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)
7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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57 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

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Sl.
No.

Initial

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Temp.
of water

Final
Temp.

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of water
Duration
of exp.

Delivery

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pressure

Delivery
Temp.

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Condense
Outlet
Pressure

Condense

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Outlet
Temp.


Pressure

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after
throttling

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Temp.
After
Throttli

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ng


Suction
pressur

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e
Suction
Temp.

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Time for
10 rev. of
compress

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or energy
meter

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Height
of water
in the
vessel

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58 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
Load Test with Capillary tube as expansion device:
1. Fill the chilled water calorimeter with pure water so that the evaporative coils are
fully immersed.

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2. Select the capillary tube line by opening the shut-off valve on this line and closing
the one on the thermostatic expansion valve line. The solenoid switch is switched OFF.
3. Start the compressor and run for some time so that the chilled water temperature
is lowered to the given test temperature.
4. Switch on the heater and slowly increase the power.

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5. Allow The temperature in water calorimeter to reach the equilibrium
temperature.
6. Connect energy meter to motor and heater by the selector switch one after another
and note down the time taken for 10 pulses of the energy meter disc.
7. Note down the pressure and temperature readings at locations 1,2,3 & 4 as

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mentioned.
8. Switch OFF the heater and the mains.
Result:
The load test on a refrigeration test rig was conducted and the results are as follows.
1. Actual C.O.P. of the system =____________.

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2. Rhetorical C.O.P. of the system = ___________.
3. Volumetric Efficiency = ___________.

Outcome:
From this experiment, conducting the load test on a refrigeration test rig and finding out the

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volumetric efficiency and co-efficient of performance for any type of refrigerant is learnt and this experiment
could be used in the areas such as Refrigerator and Air Conditioning.
Applications:
Refrigerator, Air Conditioning.

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59 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? COP
2. Which thermodynamic cycle is used in air conditioning of airplanes using air as refrigerant?
3. Define ? Ton of Refrigeration

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4. What is meant by refrigeration?
5. What is meant by air conditioning?
6. What are the four important properties of a good refrigerant?
7. How does the actual vapour compression cycle differ from that of the ideal cycle?
8. Name any four commonly used refrigerants.

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9. What are the expansion devices used in a vapour compression plant?
10. Why throttle valve is used in place of expansion cylinder for vapour compression refrigerant machine?
11. What are the merits of air refrigeration system?
12. What are the demerits of air refrigeration system?
13. Define ? Refrigerant

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14. What is net refrigerating effect of the refrigerant?
15. What are the methods to obtain sub cooling of refrigerant?

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Viva ? voce

60 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.12 EXPERIMENTS ON PSYCHROMETRIC PROCESS

Aim:

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To conduct an experiment on psychrometric processes with air conditioning system
Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch

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(iv) Digital anemometer
(v) Experimental setup
Description:
The test rig consist of
1. An air duct support of stand

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2. A blower to set up air flow through the duct along with a speed control to vary the
velocity of air.
3. A heater to rise the air temperature with regulator and energy meter.
4. Water spray, collecting tray, reservoir with gauge pump.
5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.

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(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after cooling coil).
6. The test rig consist of compressor, condenser unit placed inside trolley and fitted
with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for
condenser and (iv) Liquid receiver.
7. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and

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corrosion damage.

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61 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Observation Table: I

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Precautions:
1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence
avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kw only for the motor
circuit.
2. Natural air currents in the room if in the direction of air duct may defect the experimental results and

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hence the duct should be placed such that no wind from doors, windows, fan and cooling air from
other test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan
and should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase
beyond 240 psi.
3. Never exceed dry bulb temperatures of 40

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0
C after the heater (station 2) otherwise the air duct may be
damaged.
4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may
exceed its maximum of 32

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0
C and calibration may be affected.
5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not
running this will lead to rise in temperature at the heater and may damage the heater and the air duct.
6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their

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duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.
7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer
is placed inside the reservoir at the top. This may have to the cleaned when necessary.
8. Do not open the gate valve fully otherwise water may be splashed outside and the waster
measurement may be in error.

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S.
N
o
Inlet temp
Outlet

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temp
Pressu
re
P1
Tem

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p.
T1
Pressu
re
P2

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Temp.
T2
Pressu
re
P3

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Tem
p.
T3

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Pressu
re
P4

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Temp.
T4
Energy
for 10

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revolutio
ns
Twet Tdry Twet Tdry Lb/in
o
C Lb/in

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o
C Lb/in
o
C Lb/in
o

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C


62 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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9. If the low pressure cut out comes in to action, it means that the Freon charge is insufficient and may
have to be filled up. The suction pressure should never go below 2 psi as otherwise the compressor
seals will be damaged and air and moisture may enter the system.
10. The refrigerant strainer placed on the front panel should always be warm. If it cools and moisture
condenser on it, then the strainer might have to be charged by an experienced refrigeration

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mechanics.
11. The refrigerating system can work continuously for 2 hours, however if the room temperature is above
25
0
C the condenser may be heated up and the delivery pressure may rise. Do not exceed 240 psi.

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Pour one or two glasses of drinking water over the fins of the condenser in order to reduce the
delivery pressure.
12. After some months of operation the compressor may have to be topped up with oil and some quantity
of Freon-22 may have to be charged by an experienced mechanics.
13. See that distilled water is filled up in the plastic dishes provided under the wet bulb thermometers and

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that the wicks are in tact otherwise erroneous readings may be obtained. These thermometers will
show correct readings only when the fan is in operation.
14. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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Formulae used:
1. Corresponding to the dry and wet bulb temperature at all the stations obtain the specific enthalpy and
specific humidity values from psychrometric chart.
i.e., h1 and w1 at tb1 and tw1 and so on.
2. Air flow rate, ma = (A x V) / v4 Kg / sec

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Where, A = Area of duct at outlet in m
2
(0.46 m x 0.086 m)
V = Air velocity ( m / sec)
V4 = Specific volume of moist air at station 4 using psychometric chart m

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3
/Kg
3. Moisture added from psychrometric chart, mw1 = ma (w3-w2) Kg / sec.
Where, w3 = Specific humidity at station 3
w2 = Specific humidity at station 2

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4. Cooling effect produced on air, Qe = ma (h3 ? h4) kW.
Where, h3 = Specific enthalpy at state 3 kJ/kg
h4 = Specific enthalpy at state 4 kJ/kg
5. Moisture condensed, mcl = ma (w3 ? w4) kg/sec
Where, w3 = Specific humidity at station 3

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w4 = Specific humidity at station 4

63 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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1. Fill water in the wet bulb temperature probe trays.
2. Start the main.
3. Start the blower and run it the required speed by keeping the speed regulator at
position.
4. Start the spray pump and open the gate valve suitably.

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5. Start the heater.
6. Select the expansion device (Capillary tube / Thermostatic expansion valve)
7. Start the cooling compressor.
8. Wait for some time till thermometers shown practically constant readings and note down the
following readings:

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(i) Dry bulb temperatures tdb1, tdb2, tdb3, tdb4.
(ii) Wet bulb temperatures twb1, twb2, twb3, twb4.
(iii) Spray water temperature, ts
(iv) Surface temperature of cooler, tm ( at control panel)
(v) Pressure gauge reading, pd ( at control panel)

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(vi) Compound gauge reading, Ps ( at control panel)
(vii) Level reduction?l? in spray reservoir (mm) during 5 min.
(viii) Amount of condensate collected ?lc?, in a measuring jar at cooler tray during a
run of 5 minutes at constant conditions.
(ix) Time in second ?SH? for 10 pulses of the energy meter disc connected to the

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heater.
(x) Time in seconds Sc for 10 pulses of the energy meter disc connected to cooler
compressor.
Result:
Experiment on psychrometric processes with air conditioning system was drawn

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Outcome:
From this experiment, conducting the test on psychrometric processes with air
conditioning system is learnt and this experiment could be used in all types of air conditioning systems.

Applications:

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Air Conditioning.



64 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the commonly used unit of refrigeration?
2. Distinguish between summer air conditioning and winter air conditioning.

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3. Define ? RSHF Line
4. Define ? By Pass Factor of a Heating Coil
5. What is the effect of sub cooling a refrigerant in a vapour compression cycle?
6. What is the function of analyzer and rectifier in an absorption system?
7. What is the purpose of generator assembly in vapour absorption refrigeration system?

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8. State the substance used in the Lithium Bromide system and their functions.
9. Differentiate wet compression from dry compression.
10. Define ? Apparatus Dew Point
11. What is meant by dew point temperature?
12. Define ? Wet Bulb Temperature

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13. Define ? Degree of Saturation
14. What is meant by specific humidity?
15. Define ? Relative Humidity

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Viva ? voce

65 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.13

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PERFORMANCE TEST ON A RECIPROCATING
AIR COMPRESSOR

Aim:

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To conduct a load test on the 2 - stage reciprocating air compressor to determine the isothermal and
volumetric Efficiencies at various delivery pressures

Apparatus required:
* Air compressor with accessories.

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* Stop watch.
Description:
Two stage air compressors is a reciprocating type driven by a prime mover. The test rig consist of a base on
which the tank is mounted. The outlet of the compressor is connected to the receiver. The suction is
connected to air tank with a calibrated orifice plate through a water manometer. The input to the motor is

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recorded by an energy meter. The temperature and pressure of the air compressed is indicated by a
thermometer and pressure gauge.
Specifications:
1. Air compressor:
* LP Bore, DLP = 63.0 mm.

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* HP Bore, DHP = 79.0 mm.
* Stroke, L = 80.0 mm.
* Speed, N = 1440 rpm (5 HP)
* Effective radius = 0.193 m
2. Air receiver capacity = 0.33 m3

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3. Orifice, diameter, d0 = 12 mm
4. Orifice area,. A0 : ?d0
2
/ 4 = ----------- m
2

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5. Coefficient of discharge C d. = 0.6
6. Energy-meter constant = 200 rev / kWh

66 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I

Observation Table: II
Sl.

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No.
Actual
Discharge
Va
Theoritical

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Discharge
Vt
Volumetric
Efficiency
?

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Power
Input

Output
Power

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Overall
Efficiency
?0
Isothermal

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Workdone
IwD
Polytropic
Workdone
PwD

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Isothermal
Efficiency
?iso
m
3

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/sec m
3
/sec % kW kW % J/Kg J/Kg %

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Sl.
No.
Pressure
p
Manometer

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h1
Manometer
h2
Time for 5 revolutions Energy meter Speed of the compressor Temperature
T1

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Temperature
T1
Kg/cm
2
Cm cm sec rpm

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o
C
o
C

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67 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:

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1. Check whether manometer is filled with water up to the required level.
2. The maximum pressure in the receiver tank should not exceed 12 kg / cm
2

Procedure:

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1. Ensure that gauge pressure in the tank is zero.
2. Start the compressor. Read the receiver pressure gauge for a particular pressure.
3. Maintain the pressure constant by adjusting the outlet valve.
4. Note down the manometer reading and time taken for 3 revolution of the energy
Formulae used:

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1. Density of air at RTP:
? RTP = ? NTP X 273 Kg/ m
3

(273 + Room Temp)

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Where density of air at NTP = 1.293 Kg/ m
3
.

2. Air head causing flow:

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ha RTP = (h1 - h2) x ? water m
?a RTP
Where,
(h1- h2) = Difference in manometer liquid, in m.

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3. Actual volume at RTP:
Va RTP = C.d x Ao x ? 2 g ha RTP
Where,
C d= Coefficient of discharge = 0.6.
A o = Area of orifice = ?(d0)

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2
m
2
.
4

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Diameter of orifice d o = 0.01 m.
4. Actual volume at NTP:
Va NTP = VaRTP x T NTP
T RTP
Where,

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T NTP = Normal temp - 273
o
k
T RTP = Room temp -
o

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c (273 + TROOM )

68 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

5. Theoretical Volume of air: (at intake conditions)

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V T = ?D
2
x L x Nc m
3
/ sec.

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4 x 60
D = LP Bore diameter = 88.5 mm.
L = Stroke length = 88.9 mm.
Nc = Compressor speed rpm.
6. Volumetric Efficiency:(for LP stage)

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?vol = Va NTP x 100%
Vt
7. Shaft Input through Energy meter:

= 1 x n x ?t x ?m x 3600 kw.

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( Ec x t )
Where,
Ec = Energy meter constant = 200 rev / kWh
?t = Efficiency for transmission = 0.95.
? m = Efficiency for motor = 0.90.

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t = Time for 'n' revolution of energy meter disc.
n = no. of rev. of Energy meter disc.

8. Isothermal power:
= Pa x Va RTP x log e (R) W

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1000
Pa = Atmospheric pressure in N/ m
2
= 1.01325 x 10
5

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N / m
2
.
R = (Pressure gauge reading + atmospheric pressure)
atmospheric pressure.

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9. Isothermal efficiency:
? ISO = Isothermal power x 100%
Shaft input

Result:

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The values of isothermal and volumetric efficiency at various delivery pressures have been studied &
graph between Pressure Vs Volumetric efficiency and Pressure Vs Isothermal efficiency are drawn.


69 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Outcome:
From this experiment, conducting the load test on two stage reciprocating air compressor for
determining the isothermal and volumetric Efficiencies at various delivery pressures is understood and this
experiment could be used in the areas such as Refrigerator, Air Conditioning, IC engines, etc.

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Applications:
Refrigerator, Air Conditioning, IC engines.

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1. How are air compressors classified?
2. Define ? Isothermal Efficiency of Air Compressor
3. What is meant by FAD (Free Air Delivery)?
4. What is meant by perfect inter-cooling?
5. Define ? Clearance Ratio of an Air Compressor

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6. List out the applications of compressed air.
7. What are the types of air compressors?
8. What is meant by single acting compressor?
9. What is meant by double acting compressor?
10. What is meant by single stage compressor?

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11. What is meant by multi stage compressor?
12. Indicate the applications of reciprocating compressors in industry>
13. Define ? Mechanical Efficiency
14. What is meant by compression ratio?
15. What are the factors that affect the volumetric efficiency of a reciprocating compressor?

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Viva ? voce

70 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.14

PERFORMANCE TEST IN A HC REFRIGERATION
SYSTEM

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Aim:

To conduct the performance test on Vapour Compression Refrigeration System and to determine the
Coefficient of Performance using solenoid valve by throttling method

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Description:

In this system the working fluid is a HC out of a refrigeration system. The HC compression system is most
important system from the view point of commercial and domestic utility. The HC refrigerant at low temp and

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pressure enters the reciprocating compressor, where it is compressed isentropically and subsequently its temp
and pressure increases considerably. This HC after leaving the compressor enters the condenser where it is
cooled into low temperature. Then it is sucked by reciprocating compressor and is thus repeated.
Formula used:

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Actual COP = refrigerant effect
I/p energy to compressor
Refrigerant effect = mxCpx ? T
t
m - mass of water (kg)

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Cp - Sp. Heat of water (4.2 kJ/kg K)
?T ? decrease in temp (Ti-Ts)
t - timetaken duration of expt (sec)

Energy input =n x 3600 /k x t

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n ? number of revolutions in energy meter
t ? time taken of ?n? revolutions
k ? energy meter constant (3200)

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71 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:

Pressure of the refrigerant (Mpa) Temperature Time for n?

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rev of
energy
meter in
sec
P1 P2 P3 P4 Circulating fluid

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temp
Refrigerant temp

Ti Tf T1 T2 T3 T4

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72 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Model calculation:

Actual COP = refrigerant effect

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I/p energy to compressor

Refrigerant effect = mxCpx ? T
t
m - mass of water (kg)

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Cp - Sp. Heat of water (4.2 kJ/kg K)
?T ? decrease in temp (Ti-Ts)
t - time taken duration of experiment (sec)
Refrigerating effect = 8x4.2x (27-6)/1200=0.588 kw

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Energy input = n x 3600
n ? Number of revolutions in energy meter
t ? Time taken of ?n? revolutions
k ? Energy meter constant
=3 x 3600/(1200 x 54)

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=0.166 kW
Actual COP = refrigerant effect
I/p energy to compressor
= 0.588/0.166
=3.526

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Result:

The experiment was conducted successfully and coefficient of performance was found out is _______.

Outcome:

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From this experiment, conducting the performance test on Vapour Compression Refrigeration
System and to determine the Coefficient of Performance using solenoid valve by throttling method is
understood and this experiment could be used in the areas such as Refrigerator and Air Conditioning systems.
Applications:
Refrigerator, Air Conditioning.

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73 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the difference between air conditioning and refrigeration?
2. Write any three important properties of a good refrigerant.
3. What is the function of analyzer and rectifier in an absorption system?
4. How does humidity affect human comfort?
5. What is the commonly used unit of refrigeration?

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6. Distinguish between summer air conditioning and winter air conditioning.
7. Define ? RSHF Line
8. Define ? By Pass Factor of a Heating Coil
9. What is the effect of sub cooling a refrigerant in a vapour compression cycle?
10. What is the function of analyzer and rectifier in an absorption system?

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11. What is the purpose of generator assembly in vapour absorption refrigeration system?
12. State the substance used in the Lithium Bromide system and their functions.
13. Differentiate wet compression from dry compression.
14. Define ? Apparatus Dew Point
15. What is meant by dew point temperature?

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16. Define ? Wet Bulb Temperature
17. Define ? Degree of Saturation
18. What is meant by specific humidity?
19. Define ? Relative Humidity
20. What is meant by dew point temperature?

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Viva ? voce

74 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.15

PERFORMANCE TEST IN A FLUIDIZED BED
COOLING SYSTEM

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Aim:
To determine the performance test on cooling tower
Introduction:
The cooling tower is one of the most important device in chemical industries for example when the hot

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water come from heat exchanger we use the cooling tower to cool it The purpose of cooling tower is to cool
relatively warm water by contacting with unsaturated air. The evaporation of water mainly provides cooling. In
typical water cooling water tower warm water flows countercurrent to an airstream. Typically, the warm water
enters the top of the packed tower and cascades down through the packing , leaving at the bottom Air enters
at the bottom of the tower and flows upward through the descending water . The tower packing often consist of

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slats of plastic or of packed bed. The water is distributed by troughs and overflows to cascade over slat
gratings or packing that provides large interfacial areas of contact between the water and air in the form of
droplets and films of water. The flow of air upward through the tower can be induced by the buoyancy of the
warm air in the tower (natural draft) or by the action of a fan . The water cannot be cooled below the wet bulb
temperature. The driving force for the evaporation of water is approximately the vapour pressure of the water

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less the vapour pressure it would have at the wet bulb temperature
Procedure:
1. Introduce water and record its flow rate.
2. Switch ON the heaters on so that water is heated to the required temperature.
3. Introduce air and record its flow rate.

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4. Wait for steady state then record steady state dry and wet bulb temperature of air at the entrance and
exit.
5. Record the inlet and outlet temperature and flow rate of water also record temperature at different
stages.
Tabulation:

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Sl.No. T1 (
0
c) T2 (
0

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c) T3 (
0
c) Efficiency

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T1 = room temperature

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T2 = water inlet
T3 = water outlet

Efficiency of cooling tower

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ECT = T3/T2/*100

Model calculation:

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Efficiency of cooling tower = water outlet
--------------- *100
Water inlet

= 36/40 *100

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= 90
Result:
The performance test in cooling tower is determined as ______%.
Outcome:

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From this experiment, conducting the performance test on cooling tower is understood and this
experiment could be used in various power plants where cooling tower is used.
Applications:
Power Plant Cooling Tower, Cooling Tower.

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1. What are functions of a draught system?
2. What are the advantages of burning coal in pulverized form?
3. What are the functions of cooling tower?
4. What are the different types of draught system?

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5. What are the methods used for handling of coal?
6. What is meant by fluidized bed combustion?
7. What is the use of fluidized bed boiler?
8. What are the types of fluidized bed boiler?
9. State the purpose of condenser in fluidized bed boiler.

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10. What is meant by pulveriser and why it is used?
11. State the disadvantages of pulverized coal firing.
12. Distinguish between fouling and slagging.
Viva ? voce

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76 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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ADDITIONAL EXPERIMENTS
BEYOND THE SYLLABUS

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FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?



DEPARTMENT OF

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MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

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Name : _______________________________________

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Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION
MISSION

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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals

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To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them

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3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills

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To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering

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and to create awareness about the need for lifelong learning and pursuing advanced degrees

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PROGRAMME OUTCOMES (POs)

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On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship

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3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical

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environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination

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10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:

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1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall

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6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

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REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor

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14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus

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5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.

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10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at

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various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
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CONTENTS


Sl.No.

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Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2

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Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3
Determination of heat transfer coefficient under natural convection from a

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vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27

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CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34

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8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51

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12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72

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ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

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Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:

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(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:

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The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.

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Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts

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on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:
1. Power input, Q = V ? A / 2 W

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2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:

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1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do

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not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm

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3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm

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8. Mean temperature range = 40
0
C ? 100
0
C

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9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)

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12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)

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17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C
19. Width of gap between two heater plates (x) = 2.5 mm

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20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter
V
Ammeter
A

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Main heater (
0
C) Test Plate (
0
C)

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T1 T2 T3 T4 T5 T6



Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.

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2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.

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5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

Outcome:

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From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

Applications:

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Pipe lines, IC engines, heat exchangers

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins

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5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?

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10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?

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15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?

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20. State the advantages of dimensional analysis.

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Viva ? voce

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE

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APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:

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(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter

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Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:

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1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the

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experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:

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The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.

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L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.
No.

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Voltage
(V)
Current
(A)
Heater Temperature

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(
0
C)
Asbestos Temperature
(

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0
C)
Saw dust
Temperature (
0

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C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.

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3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by

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thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m

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2
-K

Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe

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apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:
Exhaust pipe lines, IC engines, heat exchangers

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?

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3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection

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8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?

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13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?

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18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

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Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:

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(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:

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The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is

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measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the

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relative motion of hot and cold fluid particles.

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Schematic view of the test set-up:
mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm

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2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300

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0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V

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8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

Tabulation:
Sl. No.

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Voltage Current Temperature of Thermocouple (
0
c)

V A

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T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2

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K
As = Area of heat transfer surface = ? x d x l m
2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7

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0
C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0

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C) ?
2. hL / k = A { g L
3
?T Cp ?/2v
2

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}
n

Where, hL / k are called Nusselt Number.
L

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3
g?T / v
2
is called Grashof number.
?Cp / k called Prandtl Number.

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A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid

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Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)

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0
K
-1

Where Tf = (Ts + Ta )/ 2

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For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25

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for 10
4
< Gr.Pr.<10
8

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hL / k = 0.13 (Gr.Pr)
1/3
for 10
8
< Gr.Pr.<10

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12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).

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5. Repeat the experiment at different heat inputs.

Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m

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2
K
Experimental = ______________ W/ m
2
K

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Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be

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found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)

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2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness

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7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?

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12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.

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17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No. 4

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION

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FROM A TUBE

Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater

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is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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Tabulations:

Sl. No. Voltage Current Temperature in (
0
C)

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Manometer
reading of water
in h in meter

(V) (A)

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T1

T2

T3

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T4

T5

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T6

h1
cm
h2

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cm

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Specifications:
1. Pipe diameter outside (Do) = 40 mm

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2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C

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7. Temperature Indicator = Range 0 to 300
0
C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V

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9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.

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3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W

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Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.

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3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)

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Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o
C)
= T6 ? T1.

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2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di
2

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?2gH x (?w / ?a) m
3
/hr
3. ha = qa /A(Ts- Ta) W / m
2

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K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

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Ta = Average temperature of air = (T1 + T6)/2
o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o

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C
Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

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?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

d = diameter of orifice meter = 0.014 m

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g = acceleration due to gravity = 9.81 m/s
2

using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:

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Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature

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(T1 + T6)/2
o
C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number

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K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

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k = Thermal conductivity of fluid W/m
2
K
Nu = 0.023 (Re)

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0.8
(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

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Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m
2

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K
htheoritical = -------------- W/m
2
K

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Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.

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5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.

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10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?

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15. Define ? Momentum Thickness

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Viva ? voce

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29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:

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To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different

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materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A

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channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in

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series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm

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4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.

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3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as

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Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3

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Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter

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reading
(V)
Ammeter
reading
(A)

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T1
(
0
C)
T2

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(
0
C)
T3
(

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0
C)
T4
(
0

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C)
T5
(
0
C)

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T6
(
0
C)
T7

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(
0
C)
T8
(

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0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:

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The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

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Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. Define ? Heat Transfer

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2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?

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6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?
10. Define ? Heat Exchanger

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11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

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Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

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The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input

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power and dimmer stat is provided to vary the input power.

Procedure:

1. Switch on the unit and adjust the input power to the required extent.

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2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter
reading( V)

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Ammeter
reading (A)
T1
(
0

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C)
T2
(
0
C)

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T3
(
0
C)
T4

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(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the

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inner sphere, and the outer sphere respectively.


34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Fig. 1 Apparatus of thermal conductivity of insulating powder

[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

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Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

Outcome:

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From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?

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5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?

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10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)

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15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?

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20. What is meant by steady state heat conduction?

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Viva ? voce

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36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

HEAT TRANSFER FROM PIN-FIN APPARATUS

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(NATURAL AND FORCED CONVECTION MODES)

Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:

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(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is

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connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.

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Tabulations:
Forced convection:
Sl.
No.
V I

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Fin Temperatures (
0
C)
Ambient Temp

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(
0
C)
Manometer
Reading

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(V)

(A)

T1 T2 T3 T4 T5 T6 T7 T8

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h1
cm
h2
cm

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Specifications:
1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm

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4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm

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7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.

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0
C
12. Temperature indicator = 0 ? 300
0
C

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(With compensation of ambient temperature up-to 50
0
C)
13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)

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15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8
Brass Pin Fin
Heater

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38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

16. Ammeter = 0 ? 2 A
Precautions:

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1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.

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6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:
Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,

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100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.

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5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)

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2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m
3
/s.

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Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m
3

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?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s
2

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Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

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39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

A = area of the duct
4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number

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Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2
o

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C
5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number
6. Nusselt Number:
Nu = CRe

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m
(Pr)
0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,

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Where, p = perimeter in m
k= 386 w/mk
m= ?(hp/kA)
A = area of fin = (? x D
2

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) /4
L = Length of the fin
Tw ? average temperature
T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL

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Results:
Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

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Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.

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40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Extended Surface
2. What is meant by convective mass transfer?

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3. State the applications of fins.
4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer
6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?

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8. Define ? Conduction
9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?
11. Define ? Convection
12. What is meant by transient heat conduction?

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13. What is meant by radiation?
14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

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41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.8

DETERMINATION OF STEFAN ? BOLTZMANN

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CONSTANT

Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:

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(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Geyser water
Theory:

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The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a

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hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.

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Specifications:
1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm

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5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0

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C
= (or) 0.1 Kcal / kg
0
C
9. No. of thermocouples mounted on B = 4 Nos.

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10. No. of thermocouples mounted on D = 1 No.

42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

11. Temperature indicator digital 0.1

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0
C L.C 0 - 200
0
C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.

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12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.

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Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4
? Td
4

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)
Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

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Schematic view of the test set-up:

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Heater

43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:
Proc
edur
e:
1. H

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eat the
water
in the
tank by
the immersion heater up to a temperature of about 90

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0
C.
2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling

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the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

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Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m
2
k

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4
.

Outcome:

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From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.
.Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

Sl. No.
Hemisphere Temperature(
0

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C) Avg. Temp.
of the
Hemisphere
(Th)
T4

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Steady
Temp. of
Disc
T0 (Td)
Time

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(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?

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3. State Planck?s distribution law.
4. Define ? Biot Number
5. State Wien?s displacement law.
6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.

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8. What are the various types of convection?
9. Define ? Condensation
10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?

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13. State Krichoff's law or radiation
14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

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45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.9

DETERMINATION OF EMISSIVITY OF A GREY

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SURFACE

Aim:
To measure emissivity of the test plate surface at various temperature
Apparatus required:

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(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with

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heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be

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determined.
Specifications:
1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)

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4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V

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8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300
0
C.

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.

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4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.
Tabulation:
Sl.

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No
Voltage

Current

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Black body
temp(
0
C)
Avg.

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temp.

Polished body
temp (
0

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C)
Avg.
temp.

Enclosure

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Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts
4
? Ta

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4
) A
Eb ? E = (W1 ? W2) / ? (Ts
4
? Ta

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4
) A
E = Eb ? {(W1 ? W2) / ? (Ts
4
? Ta

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4
) A}
Where,
W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W

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A = area of plates = 2 (?/4) xd
2
m
2

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T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)
Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

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47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

? = Stefan boltzman constant = 5.67 x 10
-8

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W/m
2
K
4

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Schematic view of the test set-up:


Procedure:

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1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by
the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state

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condition.

Results:
The emissivity of the test plate surface is found to be _____________.
Outcome:

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From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Emissivity
2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?
4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?

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6. What is meant by shape factor?
7. Define ? Radiation
8. What is meant by monochromatic emissive power?
9. Define ? Emissive Power
10. What is meant by absorptivity?

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11. Define ? Black Body
12. What is meant by transmissivity?
13. State Plank's distribution law
14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.10

EFFECTIVENESS OF PARALLEL / COUNTER
FLOW HEAT EXCHANGE

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Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:
(i) Experimental Setup
(ii) Stop watch

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(iii) Thermometer
Theory:
Heat exchangers are classified in three categories:
1. Transfer type
2. Storage type

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3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.
The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.

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ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water
which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by

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means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:
1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm

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3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50
0
C - 2 Nos.

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6. Thermometers (for hot water) = 0 ? 100
0
C - 2 Nos.
7. Measuring flask = 0 ? 1000 CC

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50 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

8. Geyser: single phase type to obtain hot water supply
9. Thermo Cole insulation for outer pipe.
Precautions:

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Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Tabulations:
Sl.
No.

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Flow Hot Fluid (
0
C) Cold Fluid (
0
C)

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Time for
collection of
hot fluid
Kg/sec
Time for

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collection
of cold fluid
Kg/sec
1 Parallel flow
Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)
1. Area of the pipe A = ? (D ? d) L
Where, D = inlet diameter of the outer tube

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d = outlet diameter of the inner tube
L = Length of the tube

2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

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51 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Where, m = mass flow rate Kg/ sec.
m = ?v/t, ? = density of water and t = time taken for hot water
Cp = Specific heat of capacity 4.187 kJ/kg -K

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Thi = Temperature of hot water inlet
Tho = Temperature of hot water outlet

3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W
Where, m = mass flow rate

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Cp = Specific heat of capacity
Tco = Temperature of cold water inlet
Tci = Temperature of cold water outlet
4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W
Where, Q? = (Qa + Qc) / 2

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5. Logarithmic mean temperature difference( L M T D)
?Tm = (?Ti - ?To) / In (?Ti/?To)
Where, ?To = Tho ? Tco
?Ti = Thi ? Tci
6. Over all heat transfer coefficient

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h = Q?/?Tm A W/m
2
K
where Q? = (Qa + Qc) / 2

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Procedure:
1. Place the thermometers in position and note down their readings when they are at room temperature and
no water is flowing at either side. This is required to correct the temperature.
2. Start the flow on hot water side.
3. Start the flow through annulus and run the exchanger as parallel flow unit.

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4. Put ON the geyser.
5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.
6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.
7. Keeping the flow rates same, wait till the steady state conditions are reached.
8. Record the temperatures on hot water and cold water side and also the flow rates accurately.

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9. Repeat the experiment with a counter flow under identical flow conditions.
10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Result:
1. The values of effectiveness of heat exchanger were found as
(i) Parallel flow = ________.
(ii) Counter flow = _________.

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2. Over all heat exchanger (heat transfer coefficient)
(i) Parallel flow = ________.
(ii) Counter flow = _________.

Outcome:

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From this experiment, determining the values of effectiveness of parallel and counter flow
heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat
exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Heat Exchanger
2. What are the types of heat exchangers?

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3. What is meant by indirect contact heat exchanger?
4. Write about the merits of drop wise condensation.
5. What is meant by film wise and drop wise condensation?
6. What is meant by effectiveness?
7. Define ? Direct Heat Exchanger

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8. What is meant by fouling factor?
9. Distinguish between regenerator and recuperates.
10. What is meant by parallel flow heat exchanger?
11. What is meant by counter flow heat exchanger?
12. What is meant by cross flow heat exchanger?

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13. What is meant by shell and tube heat exchanger?
Viva ? voce

53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.11

DETERMINATION OF COP OF A REFRIGERATION
SYSTEM

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Aim:
To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration
system
Apparatus required:
(i) Thermometer

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(ii) Electric Heater
(iii) Stop watch
(iv) Experimental setup
Description:
1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a

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reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.
2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated
wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a
low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the
temperature of chilled water. The above unit is located on the trolley behind front panel.

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3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic
expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum
strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure
gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high
pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy

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meter to measure the power consumed either by hater or by compressor.

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54 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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A. A compressor condenser unit placed inside trolley and fitted with
1. R-134a reciprocating compressor
2. Condenser
3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan
4. A receiver with angle check valve

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B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity
placed inside a well insulated wooden box and provided with
5. Evaporator coil
6. Stirrer
7. Electric heater 230 V, A.C.

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8. The sensing bulb of low temperature thermostat.
9. A high temperature thermostat.
10. A Thermometer to measure the chilled water temperature
C. The front panel on which are mounted the following
11. Capillary expansion tube with isolating valve.

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12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator
and isolating valve
13. Drier cum strainer and sight glass
14. Thermostat at inlet and outlet of both evaporator and condenser
15. Pressure gauge at inlet and outlet of evaporator and condenser

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16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out
17. Heat power regulator switch and regulator
18. Energy meter to measure the power consumed either by hater or by compressor.

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55 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.

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2. The heater regulator should be switched off whenever not in use. Heating water beyond 40
0
C may lead to
permanent damage of the entire system. A high temperature cut off thermostat is provided in the water
chiller, to cut off the heater beyond 30

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0
C.Check the setting of the same before operation.
3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.
4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.
5. The solenoid thermostat is adjusted to cut at 15

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0
C and cut in at 10
0
C of the chilled water. Do not alter the
same.

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6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.
7. The space near the condenser should permit good ventilation to aid proper fan performance.
8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked
in
0

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F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,
calibrated in SI units, are not available.)
9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to
obtain the pressure in MN/m
2

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.e.g. P = x psig
= (x + 14.7) psia
= (x + 14.7) / 145 MN/m
2
(MPa)

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10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.
Formulae used:
Let, State 1 indicates the entry of compressor.
State 2 indicates the exit of compressor.
State 3 indicates the exit from condenser.

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State 4 indicates the entry to evaporator
P = Pressure (bar)
T = Temperature (
0
C)

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H = Specific enthalpy (kJ/kg)
v = Specific Volume (m
3
/Kg)
n = Number of revolutions of energy meter disc.

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t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)
t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)
K = Energy meter constant = 3200 lmp / kWh
N = Speed of compressor = 2840 rpm
h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

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56 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2
h3 = Specific enthalpy at Pc and T3 (kJ/kg)

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h4 = h3
Stroke volume of compressor = (?/ 4) d
2
l = 12.58 x 10
-6

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m
3

1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar
2. Average condenser pressure, Pc = (P2 + P3) / 2 bar

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3. Heater input, Qe = (n / t1) x (3600 / k) kW
4. Compressor input, W = (n / t2) x (3600 / k) kW
5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1
6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)
7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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57 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

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Sl.
No.

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Initial
Temp.
of water

Final

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Temp.
of water
Duration
of exp.

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Delivery
pressure

Delivery
Temp.

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Condense
Outlet
Pressure

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Condense
Outlet
Temp.

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Pressure
after
throttling

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Temp.
After

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Throttli
ng


Suction

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pressur
e
Suction
Temp.

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Time for
10 rev. of

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compress
or energy
meter

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Height
of water
in the
vessel

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58 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
Load Test with Capillary tube as expansion device:
1. Fill the chilled water calorimeter with pure water so that the evaporative coils are

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fully immersed.
2. Select the capillary tube line by opening the shut-off valve on this line and closing
the one on the thermostatic expansion valve line. The solenoid switch is switched OFF.
3. Start the compressor and run for some time so that the chilled water temperature
is lowered to the given test temperature.

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4. Switch on the heater and slowly increase the power.
5. Allow The temperature in water calorimeter to reach the equilibrium
temperature.
6. Connect energy meter to motor and heater by the selector switch one after another
and note down the time taken for 10 pulses of the energy meter disc.

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7. Note down the pressure and temperature readings at locations 1,2,3 & 4 as
mentioned.
8. Switch OFF the heater and the mains.
Result:
The load test on a refrigeration test rig was conducted and the results are as follows.

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1. Actual C.O.P. of the system =____________.
2. Rhetorical C.O.P. of the system = ___________.
3. Volumetric Efficiency = ___________.

Outcome:

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From this experiment, conducting the load test on a refrigeration test rig and finding out the
volumetric efficiency and co-efficient of performance for any type of refrigerant is learnt and this experiment
could be used in the areas such as Refrigerator and Air Conditioning.
Applications:
Refrigerator, Air Conditioning.

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59 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? COP
2. Which thermodynamic cycle is used in air conditioning of airplanes using air as refrigerant?

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3. Define ? Ton of Refrigeration
4. What is meant by refrigeration?
5. What is meant by air conditioning?
6. What are the four important properties of a good refrigerant?
7. How does the actual vapour compression cycle differ from that of the ideal cycle?

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8. Name any four commonly used refrigerants.
9. What are the expansion devices used in a vapour compression plant?
10. Why throttle valve is used in place of expansion cylinder for vapour compression refrigerant machine?
11. What are the merits of air refrigeration system?
12. What are the demerits of air refrigeration system?

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13. Define ? Refrigerant
14. What is net refrigerating effect of the refrigerant?
15. What are the methods to obtain sub cooling of refrigerant?

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Viva ? voce

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60 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.12 EXPERIMENTS ON PSYCHROMETRIC PROCESS

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Aim:
To conduct an experiment on psychrometric processes with air conditioning system
Apparatus required:
(i) Thermometer
(ii) Electric Heater

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(iii) Stop watch
(iv) Digital anemometer
(v) Experimental setup
Description:
The test rig consist of

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1. An air duct support of stand
2. A blower to set up air flow through the duct along with a speed control to vary the
velocity of air.
3. A heater to rise the air temperature with regulator and energy meter.
4. Water spray, collecting tray, reservoir with gauge pump.

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5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.
(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after cooling coil).
6. The test rig consist of compressor, condenser unit placed inside trolley and fitted
with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for
condenser and (iv) Liquid receiver.

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7. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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61 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Observation Table: I

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Precautions:
1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence
avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kw only for the motor
circuit.

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2. Natural air currents in the room if in the direction of air duct may defect the experimental results and
hence the duct should be placed such that no wind from doors, windows, fan and cooling air from
other test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan
and should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase
beyond 240 psi.

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3. Never exceed dry bulb temperatures of 40
0
C after the heater (station 2) otherwise the air duct may be
damaged.
4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may

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exceed its maximum of 32
0
C and calibration may be affected.
5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not
running this will lead to rise in temperature at the heater and may damage the heater and the air duct.

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6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their
duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.
7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer
is placed inside the reservoir at the top. This may have to the cleaned when necessary.
8. Do not open the gate valve fully otherwise water may be splashed outside and the waster

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measurement may be in error.
S.
N
o
Inlet temp

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Outlet
temp
Pressu
re
P1

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Tem
p.
T1
Pressu
re

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P2
Temp.
T2
Pressu
re

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P3

Tem
p.
T3

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Pressu
re
P4

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Temp.
T4
Energy

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for 10
revolutio
ns
Twet Tdry Twet Tdry Lb/in
o

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C Lb/in
o
C Lb/in
o
C Lb/in

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o
C


62 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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9. If the low pressure cut out comes in to action, it means that the Freon charge is insufficient and may
have to be filled up. The suction pressure should never go below 2 psi as otherwise the compressor
seals will be damaged and air and moisture may enter the system.
10. The refrigerant strainer placed on the front panel should always be warm. If it cools and moisture

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condenser on it, then the strainer might have to be charged by an experienced refrigeration
mechanics.
11. The refrigerating system can work continuously for 2 hours, however if the room temperature is above
25
0

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C the condenser may be heated up and the delivery pressure may rise. Do not exceed 240 psi.
Pour one or two glasses of drinking water over the fins of the condenser in order to reduce the
delivery pressure.
12. After some months of operation the compressor may have to be topped up with oil and some quantity
of Freon-22 may have to be charged by an experienced mechanics.

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13. See that distilled water is filled up in the plastic dishes provided under the wet bulb thermometers and
that the wicks are in tact otherwise erroneous readings may be obtained. These thermometers will
show correct readings only when the fan is in operation.
14. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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Formulae used:
1. Corresponding to the dry and wet bulb temperature at all the stations obtain the specific enthalpy and
specific humidity values from psychrometric chart.
i.e., h1 and w1 at tb1 and tw1 and so on.

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2. Air flow rate, ma = (A x V) / v4 Kg / sec
Where, A = Area of duct at outlet in m
2
(0.46 m x 0.086 m)
V = Air velocity ( m / sec)

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V4 = Specific volume of moist air at station 4 using psychometric chart m
3
/Kg
3. Moisture added from psychrometric chart, mw1 = ma (w3-w2) Kg / sec.
Where, w3 = Specific humidity at station 3

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w2 = Specific humidity at station 2
4. Cooling effect produced on air, Qe = ma (h3 ? h4) kW.
Where, h3 = Specific enthalpy at state 3 kJ/kg
h4 = Specific enthalpy at state 4 kJ/kg
5. Moisture condensed, mcl = ma (w3 ? w4) kg/sec

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Where, w3 = Specific humidity at station 3
w4 = Specific humidity at station 4

63 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Fill water in the wet bulb temperature probe trays.
2. Start the main.
3. Start the blower and run it the required speed by keeping the speed regulator at
position.

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4. Start the spray pump and open the gate valve suitably.
5. Start the heater.
6. Select the expansion device (Capillary tube / Thermostatic expansion valve)
7. Start the cooling compressor.
8. Wait for some time till thermometers shown practically constant readings and note down the

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following readings:
(i) Dry bulb temperatures tdb1, tdb2, tdb3, tdb4.
(ii) Wet bulb temperatures twb1, twb2, twb3, twb4.
(iii) Spray water temperature, ts
(iv) Surface temperature of cooler, tm ( at control panel)

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(v) Pressure gauge reading, pd ( at control panel)
(vi) Compound gauge reading, Ps ( at control panel)
(vii) Level reduction?l? in spray reservoir (mm) during 5 min.
(viii) Amount of condensate collected ?lc?, in a measuring jar at cooler tray during a
run of 5 minutes at constant conditions.

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(ix) Time in second ?SH? for 10 pulses of the energy meter disc connected to the
heater.
(x) Time in seconds Sc for 10 pulses of the energy meter disc connected to cooler
compressor.
Result:

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Experiment on psychrometric processes with air conditioning system was drawn
Outcome:
From this experiment, conducting the test on psychrometric processes with air
conditioning system is learnt and this experiment could be used in all types of air conditioning systems.

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Applications:
Air Conditioning.

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64 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is the commonly used unit of refrigeration?

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2. Distinguish between summer air conditioning and winter air conditioning.
3. Define ? RSHF Line
4. Define ? By Pass Factor of a Heating Coil
5. What is the effect of sub cooling a refrigerant in a vapour compression cycle?
6. What is the function of analyzer and rectifier in an absorption system?

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7. What is the purpose of generator assembly in vapour absorption refrigeration system?
8. State the substance used in the Lithium Bromide system and their functions.
9. Differentiate wet compression from dry compression.
10. Define ? Apparatus Dew Point
11. What is meant by dew point temperature?

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12. Define ? Wet Bulb Temperature
13. Define ? Degree of Saturation
14. What is meant by specific humidity?
15. Define ? Relative Humidity

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Viva ? voce

65 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.13

PERFORMANCE TEST ON A RECIPROCATING
AIR COMPRESSOR

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Aim:
To conduct a load test on the 2 - stage reciprocating air compressor to determine the isothermal and
volumetric Efficiencies at various delivery pressures

Apparatus required:

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* Air compressor with accessories.
* Stop watch.
Description:
Two stage air compressors is a reciprocating type driven by a prime mover. The test rig consist of a base on
which the tank is mounted. The outlet of the compressor is connected to the receiver. The suction is

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connected to air tank with a calibrated orifice plate through a water manometer. The input to the motor is
recorded by an energy meter. The temperature and pressure of the air compressed is indicated by a
thermometer and pressure gauge.
Specifications:
1. Air compressor:

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* LP Bore, DLP = 63.0 mm.
* HP Bore, DHP = 79.0 mm.
* Stroke, L = 80.0 mm.
* Speed, N = 1440 rpm (5 HP)
* Effective radius = 0.193 m

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2. Air receiver capacity = 0.33 m3
3. Orifice, diameter, d0 = 12 mm
4. Orifice area,. A0 : ?d0
2
/ 4 = ----------- m

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2

5. Coefficient of discharge C d. = 0.6
6. Energy-meter constant = 200 rev / kWh

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66 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

Observation Table: II

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Sl.
No.
Actual
Discharge
Va

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Theoritical
Discharge
Vt
Volumetric
Efficiency

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?
Power
Input

Output

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Power

Overall
Efficiency
?0

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Isothermal
Workdone
IwD
Polytropic
Workdone

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PwD
Isothermal
Efficiency
?iso
m

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3
/sec m
3
/sec % kW kW % J/Kg J/Kg %

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Sl.
No.
Pressure
p

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Manometer
h1
Manometer
h2
Time for 5 revolutions Energy meter Speed of the compressor Temperature

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T1
Temperature
T1
Kg/cm
2

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Cm cm sec rpm
o
C
o
C

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67 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Check whether manometer is filled with water up to the required level.
2. The maximum pressure in the receiver tank should not exceed 12 kg / cm
2

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Procedure:
1. Ensure that gauge pressure in the tank is zero.
2. Start the compressor. Read the receiver pressure gauge for a particular pressure.
3. Maintain the pressure constant by adjusting the outlet valve.
4. Note down the manometer reading and time taken for 3 revolution of the energy

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Formulae used:
1. Density of air at RTP:
? RTP = ? NTP X 273 Kg/ m
3

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(273 + Room Temp)
Where density of air at NTP = 1.293 Kg/ m
3
.

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2. Air head causing flow:
ha RTP = (h1 - h2) x ? water m
?a RTP
Where,
(h1- h2) = Difference in manometer liquid, in m.

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3. Actual volume at RTP:
Va RTP = C.d x Ao x ? 2 g ha RTP
Where,
C d= Coefficient of discharge = 0.6.

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A o = Area of orifice = ?(d0)
2
m
2
.

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4
Diameter of orifice d o = 0.01 m.
4. Actual volume at NTP:
Va NTP = VaRTP x T NTP
T RTP

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Where,
T NTP = Normal temp - 273
o
k
T RTP = Room temp -

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o
c (273 + TROOM )

68 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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5. Theoretical Volume of air: (at intake conditions)
V T = ?D
2
x L x Nc m
3

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/ sec.
4 x 60
D = LP Bore diameter = 88.5 mm.
L = Stroke length = 88.9 mm.
Nc = Compressor speed rpm.

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6. Volumetric Efficiency:(for LP stage)
?vol = Va NTP x 100%
Vt
7. Shaft Input through Energy meter:

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= 1 x n x ?t x ?m x 3600 kw.
( Ec x t )
Where,
Ec = Energy meter constant = 200 rev / kWh
?t = Efficiency for transmission = 0.95.

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? m = Efficiency for motor = 0.90.
t = Time for 'n' revolution of energy meter disc.
n = no. of rev. of Energy meter disc.

8. Isothermal power:

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= Pa x Va RTP x log e (R) W
1000
Pa = Atmospheric pressure in N/ m
2
= 1.01325 x 10

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5
N / m
2
.
R = (Pressure gauge reading + atmospheric pressure)

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atmospheric pressure.
9. Isothermal efficiency:
? ISO = Isothermal power x 100%
Shaft input

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Result:
The values of isothermal and volumetric efficiency at various delivery pressures have been studied &
graph between Pressure Vs Volumetric efficiency and Pressure Vs Isothermal efficiency are drawn.

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69 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Outcome:
From this experiment, conducting the load test on two stage reciprocating air compressor for
determining the isothermal and volumetric Efficiencies at various delivery pressures is understood and this

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experiment could be used in the areas such as Refrigerator, Air Conditioning, IC engines, etc.

Applications:
Refrigerator, Air Conditioning, IC engines.

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1. How are air compressors classified?
2. Define ? Isothermal Efficiency of Air Compressor
3. What is meant by FAD (Free Air Delivery)?
4. What is meant by perfect inter-cooling?

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5. Define ? Clearance Ratio of an Air Compressor
6. List out the applications of compressed air.
7. What are the types of air compressors?
8. What is meant by single acting compressor?
9. What is meant by double acting compressor?

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10. What is meant by single stage compressor?
11. What is meant by multi stage compressor?
12. Indicate the applications of reciprocating compressors in industry>
13. Define ? Mechanical Efficiency
14. What is meant by compression ratio?

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15. What are the factors that affect the volumetric efficiency of a reciprocating compressor?

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Viva ? voce

70 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.14

PERFORMANCE TEST IN A HC REFRIGERATION
SYSTEM

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Aim:

To conduct the performance test on Vapour Compression Refrigeration System and to determine the

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Coefficient of Performance using solenoid valve by throttling method

Description:

In this system the working fluid is a HC out of a refrigeration system. The HC compression system is most

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important system from the view point of commercial and domestic utility. The HC refrigerant at low temp and
pressure enters the reciprocating compressor, where it is compressed isentropically and subsequently its temp
and pressure increases considerably. This HC after leaving the compressor enters the condenser where it is
cooled into low temperature. Then it is sucked by reciprocating compressor and is thus repeated.
Formula used:

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Actual COP = refrigerant effect
I/p energy to compressor
Refrigerant effect = mxCpx ? T
t

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m - mass of water (kg)
Cp - Sp. Heat of water (4.2 kJ/kg K)
?T ? decrease in temp (Ti-Ts)
t - timetaken duration of expt (sec)

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Energy input =n x 3600 /k x t
n ? number of revolutions in energy meter
t ? time taken of ?n? revolutions
k ? energy meter constant (3200)

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71 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:

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Pressure of the refrigerant (Mpa) Temperature Time for n?
rev of
energy
meter in
sec

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P1 P2 P3 P4 Circulating fluid
temp
Refrigerant temp

Ti Tf T1 T2 T3 T4

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72 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Model calculation:

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Actual COP = refrigerant effect
I/p energy to compressor

Refrigerant effect = mxCpx ? T
t

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m - mass of water (kg)
Cp - Sp. Heat of water (4.2 kJ/kg K)
?T ? decrease in temp (Ti-Ts)
t - time taken duration of experiment (sec)
Refrigerating effect = 8x4.2x (27-6)/1200=0.588 kw

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Energy input = n x 3600
n ? Number of revolutions in energy meter
t ? Time taken of ?n? revolutions
k ? Energy meter constant

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=3 x 3600/(1200 x 54)
=0.166 kW
Actual COP = refrigerant effect
I/p energy to compressor
= 0.588/0.166

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=3.526
Result:

The experiment was conducted successfully and coefficient of performance was found out is _______.

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Outcome:
From this experiment, conducting the performance test on Vapour Compression Refrigeration
System and to determine the Coefficient of Performance using solenoid valve by throttling method is
understood and this experiment could be used in the areas such as Refrigerator and Air Conditioning systems.
Applications:

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Refrigerator, Air Conditioning.

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73 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the difference between air conditioning and refrigeration?
2. Write any three important properties of a good refrigerant.
3. What is the function of analyzer and rectifier in an absorption system?
4. How does humidity affect human comfort?

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5. What is the commonly used unit of refrigeration?
6. Distinguish between summer air conditioning and winter air conditioning.
7. Define ? RSHF Line
8. Define ? By Pass Factor of a Heating Coil
9. What is the effect of sub cooling a refrigerant in a vapour compression cycle?

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10. What is the function of analyzer and rectifier in an absorption system?
11. What is the purpose of generator assembly in vapour absorption refrigeration system?
12. State the substance used in the Lithium Bromide system and their functions.
13. Differentiate wet compression from dry compression.
14. Define ? Apparatus Dew Point

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15. What is meant by dew point temperature?
16. Define ? Wet Bulb Temperature
17. Define ? Degree of Saturation
18. What is meant by specific humidity?
19. Define ? Relative Humidity

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20. What is meant by dew point temperature?

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Viva ? voce

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74 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.15

PERFORMANCE TEST IN A FLUIDIZED BED

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COOLING SYSTEM

Aim:
To determine the performance test on cooling tower
Introduction:

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The cooling tower is one of the most important device in chemical industries for example when the hot
water come from heat exchanger we use the cooling tower to cool it The purpose of cooling tower is to cool
relatively warm water by contacting with unsaturated air. The evaporation of water mainly provides cooling. In
typical water cooling water tower warm water flows countercurrent to an airstream. Typically, the warm water
enters the top of the packed tower and cascades down through the packing , leaving at the bottom Air enters

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at the bottom of the tower and flows upward through the descending water . The tower packing often consist of
slats of plastic or of packed bed. The water is distributed by troughs and overflows to cascade over slat
gratings or packing that provides large interfacial areas of contact between the water and air in the form of
droplets and films of water. The flow of air upward through the tower can be induced by the buoyancy of the
warm air in the tower (natural draft) or by the action of a fan . The water cannot be cooled below the wet bulb

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temperature. The driving force for the evaporation of water is approximately the vapour pressure of the water
less the vapour pressure it would have at the wet bulb temperature
Procedure:
1. Introduce water and record its flow rate.
2. Switch ON the heaters on so that water is heated to the required temperature.

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3. Introduce air and record its flow rate.
4. Wait for steady state then record steady state dry and wet bulb temperature of air at the entrance and
exit.
5. Record the inlet and outlet temperature and flow rate of water also record temperature at different
stages.

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Tabulation:

Sl.No. T1 (
0
c) T2 (

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0
c) T3 (
0
c) Efficiency

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T1 = room temperature

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T2 = water inlet
T3 = water outlet

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Efficiency of cooling tower

ECT = T3/T2/*100

Model calculation:

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Efficiency of cooling tower = water outlet
--------------- *100
Water inlet

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= 36/40 *100

= 90
Result:
The performance test in cooling tower is determined as ______%.

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Outcome:
From this experiment, conducting the performance test on cooling tower is understood and this
experiment could be used in various power plants where cooling tower is used.
Applications:
Power Plant Cooling Tower, Cooling Tower.

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1. What are functions of a draught system?
2. What are the advantages of burning coal in pulverized form?
3. What are the functions of cooling tower?

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4. What are the different types of draught system?
5. What are the methods used for handling of coal?
6. What is meant by fluidized bed combustion?
7. What is the use of fluidized bed boiler?
8. What are the types of fluidized bed boiler?

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9. State the purpose of condenser in fluidized bed boiler.
10. What is meant by pulveriser and why it is used?
11. State the disadvantages of pulverized coal firing.
12. Distinguish between fouling and slagging.
Viva ? voce

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ADDITIONAL EXPERIMENTS
BEYOND THE SYLLABUS

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77 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.16 AIR CONDITIONING TEST RIG

Aim:
To conduct a performance test on air conditioning test rig and determine the Coefficient of Performance of
air conditioning system

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Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Digital anemometer

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(v) Experimental setup
Description:
The test rig consist of
1. An air duct support of stand
2. A blower to set up air flow through the duct along with a speed control to vary the

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velocity of air.
3. A heater to rise the air temperature with regulator and energy meter.
4. Water spray, collecting tray, reservoir with gauge pump.
5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.
(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after

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cooling coil).
6. The test rig consists of compressor, condenser unit placed inside trolley and fitted
with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan
for condenser and (iv) Liquid receiver.

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FirstRanker.com - FirstRanker's Choice

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1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL

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2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels

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? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION

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MISSION
VISION
MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals

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2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which

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enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt

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and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able

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1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution

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5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both

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verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus

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3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)

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8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:

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11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus

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3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction

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7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-

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efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.

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15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
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CONTENTS

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Sl.No.
Name of the experiment
Page No.

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CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus

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11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15

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4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6

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Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43

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10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63

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14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75

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PROJECT WORK 81

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Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:

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To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in

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which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.

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Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d

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2
(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.

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4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

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Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm

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5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0

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C ? 100
0
C
9. Maximum temperature of the hot plate = 170
0

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C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V

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14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200

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0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter

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V
Ammeter
A
Main heater (
0

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C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.

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3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.

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7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be

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k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat

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exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

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1. Define ? Thermal Conductivity

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2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?

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7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.

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12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.

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17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

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Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus

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(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is

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transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside

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an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm

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3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.

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3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)

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Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found

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Tabulation:
Sl.
No.
Voltage
(V)

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Current
(A)
Heater Temperature
(
0

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C)
Asbestos Temperature
(
0
C)

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Saw dust
Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.

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5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.

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Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?

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5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?

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10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow

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15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.

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20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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Expt. No.3

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:

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To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple

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(iii) Ammeter
(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of

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the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

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When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Schematic view of the test set-up:
mm
mm

19 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm

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4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel

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thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0

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c)

V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Heat transfer coefficient is given by

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h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m

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2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C

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q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L

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3
?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v

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2
is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface

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K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid

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G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K

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-1

Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been

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determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25
for 10
4

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< Gr.Pr.<10
8

hL / k = 0.13 (Gr.Pr)
1/3

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for 10
8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.

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2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

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Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K

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Experimental = ______________ W/ m
2
K

Outcomes:

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From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.

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4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.

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9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?

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14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness

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19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

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Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer

Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band

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heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to

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measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.


24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

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Sl. No. Voltage Current Temperature in (
0
C)
Manometer
reading of water

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in h in meter

(V) (A)
T1

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T2

T3

T4

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T5

T6

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h1
cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm

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4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0

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C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.

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5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference

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in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.

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4. Note down the heater input.

26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:

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1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (

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o
C)
= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr

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Q = Volume flow rate
Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m
3

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/hr
3. ha = qa /A(Ts- Ta) W / m
2
K
qa = Rate of which air is getting heated.

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A = Test section area = ? x Di x L m
2

Ta = Average temperature of air = (T1 + T6)/2
o

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C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C
Cd = 0.64

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H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m

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3

d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

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using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di

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2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o

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C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings

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6. Prandtl Number:

27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k

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Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

k = Thermal conductivity of fluid W/m

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2
K
Nu = 0.023 (Re)
0.8
(Pr)

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0.4
Bulk mean temperature = (T1 + T6)/2

Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection

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apparatus.
hactual = -------------- W/m
2
K
htheoritical = -------------- W/m

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2
K

Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection

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apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is meant by boiling and condensation?

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2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?

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7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?

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12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:

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When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly

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temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The

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apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:

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1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:

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1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.

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5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)

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6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.

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Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities

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Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter
reading
(V)

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Ammeter
reading
(A)
T1
(

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0
C)
T2
(
0

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C)
T3
(
0
C)

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T4
(
0
C)
T5

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(
0
C)
T6
(

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0
C)
T7
(
0

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C)
T8
(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W

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b. Wood section = ---------------W
c. Asbestos section = ------------W

Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt

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and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.

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4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.

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8. Explain the significance of Fourier number.
9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

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DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

Aim:

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To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and

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T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

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Procedure:

1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.

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4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.


The readings are tabulated below

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Sl.No. Voltmeter
reading( V)
Ammeter
reading (A)

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T1
(
0
C)
T2

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(
0
C)
T3
(

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0
C)
T4
(
0

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C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm

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The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Fig. 1 Apparatus of thermal conductivity of insulating powder

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[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

Result:

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The thermal conductivity of insulating powder by conduction is found and the result is, ___________

Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is

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analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is the need for conducting this experiment?

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2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.

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7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?

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12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?

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17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.7

HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

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Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer
Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the

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fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:

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Sl.
No.
V I

Fin Temperatures (

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0
C)
Ambient Temp
(
0

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C)
Manometer
Reading
(V)

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(A)

T1 T2 T3 T4 T5 T6 T7 T8
h1
cm

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h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:

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1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

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Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor

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9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C

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12. Temperature indicator = 0 ? 300
0
C
(With compensation of ambient temperature up-to 50
0

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C)
13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1

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T8
Brass Pin Fin
Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.

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3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.

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Procedure:
Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.

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3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)

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1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2

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) /4}?2gha m
3
/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m

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?w Density of water = 1000 kg/m
3

?a = Density of air = 1.165 kg/m
3

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g = acceleration due to gravity = 9.81 m/s
2

Cd = Coefficient of discharge = 0.64
D = diameter of the orifice

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3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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A = area of the duct
4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin

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v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2
o
C
5. Heat transfer coefficient, h = Nu k / D

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Where Nu = Nusselt Number
6. Nusselt Number:
Nu = CRe
m
(Pr)

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0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk

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m= ?(hp/kA)
A = area of fin = (? x D
2
) /4
L = Length of the fin

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Tw ? average temperature
T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were

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Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced

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convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.

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40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?

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5. Define ? Heat Transfer
6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?

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10. What is meant by steady state heat conduction?
11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number

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15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.8

DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

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Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer
(ii) Electric Heater

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(iii) Stop watch
(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.

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The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on

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the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm

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2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm

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7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C
= (or) 0.1 Kcal / kg

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0
C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

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42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

11. Temperature indicator digital 0.1
0
C L.C 0 - 200

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0
C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water

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Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th

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4
? Td
4
)
Where, A = area of the disc

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Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

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43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulations:
Proc

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edur
e:
1. H
eat the
water

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in the
tank by
the immersion heater up to a temperature of about 90
0
C.

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2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.

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5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

Result:

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The Stefan Boltzman constant was found out to be = _______________________ m/m
2
k
4
.

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Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,

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Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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Sl. No.
Hemisphere Temperature(
0
C) Avg. Temp.
of the

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Hemisphere
(Th)
T4
Steady
Temp. of

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Disc
T0 (Td)
Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number

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5. State Wien?s displacement law.
6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation

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10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?

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15. Explain the concept of black body.

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Viva ? voce

45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.9

DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

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Aim:
To measure emissivity of the test plate surface at various temperature
Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer
Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats

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and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.
Specifications:

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1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each

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5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.

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10. Temperature Indicator = 0 ? 300
0
C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:

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1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.

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6. See that the black plate is having a layer of lamp black uniformly.
Tabulation:
Sl.
No
Voltage

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Current

Black body
temp(

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0
C)
Avg.
temp.

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Polished body
temp (
0
C)
Avg.

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temp.

Enclosure
Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,

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W1 ? W2 = (Eb ? E) ? (Ts
4
? Ta
4
) A

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Eb ? E = (W1 ? W2) / ? (Ts
4
? Ta
4
) A

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E = Eb ? {(W1 ? W2) / ? (Ts
4
? Ta
4
) A}

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Where,
W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd
2

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m
2

T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure

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Ts = surface temperature of the discs (or T1)
Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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? = Stefan boltzman constant = 5.67 x 10
-8
W/m
2

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K
4


Schematic view of the test set-up:

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Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,

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2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by
the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

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Results:
The emissivity of the test plate surface is found to be _____________.
Outcome:
From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Emissivity
2. State Kirchoff?s law of radiation.

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3. What is meant by reflectivity?
4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?
6. What is meant by shape factor?
7. Define ? Radiation

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8. What is meant by monochromatic emissive power?
9. Define ? Emissive Power
10. What is meant by absorptivity?
11. Define ? Black Body
12. What is meant by transmissivity?

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13. State Plank's distribution law
14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

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49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.10

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EFFECTIVENESS OF PARALLEL / COUNTER
FLOW HEAT EXCHANGE

Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow

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Apparatus required:
(i) Experimental Setup
(ii) Stop watch
(iii) Thermometer
Theory:

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Heat exchangers are classified in three categories:
1. Transfer type
2. Storage type
3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is

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transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.
The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.

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The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water
which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.

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Specifications:
1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm

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5. Thermometers (for cold water) = 0 ? 50
0
C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100
0

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C - 2 Nos.
7. Measuring flask = 0 ? 1000 CC

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8. Geyser: single phase type to obtain hot water supply
9. Thermo Cole insulation for outer pipe.
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.

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Tabulations:
Sl.
No.
Flow Hot Fluid (
0

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C) Cold Fluid (
0
C)
Time for
collection of

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hot fluid
Kg/sec
Time for
collection
of cold fluid

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Kg/sec
1 Parallel flow
Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)
1. Area of the pipe A = ? (D ? d) L
Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube
L = Length of the tube

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2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

51 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Where, m = mass flow rate Kg/ sec.
m = ?v/t, ? = density of water and t = time taken for hot water
Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet
Tho = Temperature of hot water outlet

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3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W
Where, m = mass flow rate
Cp = Specific heat of capacity
Tco = Temperature of cold water inlet

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Tci = Temperature of cold water outlet
4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W
Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)
?Tm = (?Ti - ?To) / In (?Ti/?To)

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Where, ?To = Tho ? Tco
?Ti = Thi ? Tci
6. Over all heat transfer coefficient
h = Q?/?Tm A W/m
2

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K
where Q? = (Qa + Qc) / 2

Procedure:
1. Place the thermometers in position and note down their readings when they are at room temperature and

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no water is flowing at either side. This is required to correct the temperature.
2. Start the flow on hot water side.
3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.
5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.

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6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.
7. Keeping the flow rates same, wait till the steady state conditions are reached.
8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.
10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

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52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Result:

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1. The values of effectiveness of heat exchanger were found as
(i) Parallel flow = ________.
(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)
(i) Parallel flow = ________.

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(ii) Counter flow = _________.

Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow
heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat

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exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Heat Exchanger
2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?
4. Write about the merits of drop wise condensation.

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5. What is meant by film wise and drop wise condensation?
6. What is meant by effectiveness?
7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?
9. Distinguish between regenerator and recuperates.

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10. What is meant by parallel flow heat exchanger?
11. What is meant by counter flow heat exchanger?
12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?
Viva ? voce

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53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.11

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DETERMINATION OF COP OF A REFRIGERATION
SYSTEM

Aim:
To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration

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system
Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch

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(iv) Experimental setup
Description:
1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a
reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.
2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated

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wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a
low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the
temperature of chilled water. The above unit is located on the trolley behind front panel.
3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic
expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum

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strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure
gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high
pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy
meter to measure the power consumed either by hater or by compressor.

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54 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
A. A compressor condenser unit placed inside trolley and fitted with
1. R-134a reciprocating compressor

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2. Condenser
3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan
4. A receiver with angle check valve
B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity
placed inside a well insulated wooden box and provided with

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5. Evaporator coil
6. Stirrer
7. Electric heater 230 V, A.C.
8. The sensing bulb of low temperature thermostat.
9. A high temperature thermostat.

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10. A Thermometer to measure the chilled water temperature
C. The front panel on which are mounted the following
11. Capillary expansion tube with isolating valve.
12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator
and isolating valve

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13. Drier cum strainer and sight glass
14. Thermostat at inlet and outlet of both evaporator and condenser
15. Pressure gauge at inlet and outlet of evaporator and condenser
16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out
17. Heat power regulator switch and regulator

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18. Energy meter to measure the power consumed either by hater or by compressor.



55 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.
2. The heater regulator should be switched off whenever not in use. Heating water beyond 40
0

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C may lead to
permanent damage of the entire system. A high temperature cut off thermostat is provided in the water
chiller, to cut off the heater beyond 30
0
C.Check the setting of the same before operation.

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3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.
4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.
5. The solenoid thermostat is adjusted to cut at 15
0
C and cut in at 10

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0
C of the chilled water. Do not alter the
same.
6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.
7. The space near the condenser should permit good ventilation to aid proper fan performance.

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8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked
in
0
F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,
calibrated in SI units, are not available.)

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9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to
obtain the pressure in MN/m
2
.e.g. P = x psig
= (x + 14.7) psia

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= (x + 14.7) / 145 MN/m
2
(MPa)
10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.
Formulae used:

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Let, State 1 indicates the entry of compressor.
State 2 indicates the exit of compressor.
State 3 indicates the exit from condenser.
State 4 indicates the entry to evaporator
P = Pressure (bar)

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T = Temperature (
0
C)
H = Specific enthalpy (kJ/kg)
v = Specific Volume (m

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3
/Kg)
n = Number of revolutions of energy meter disc.
t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)
t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)

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K = Energy meter constant = 3200 lmp / kWh
N = Speed of compressor = 2840 rpm
h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

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h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2
h3 = Specific enthalpy at Pc and T3 (kJ/kg)
h4 = h3
Stroke volume of compressor = (?/ 4) d

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2
l = 12.58 x 10
-6
m
3

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1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar
2. Average condenser pressure, Pc = (P2 + P3) / 2 bar
3. Heater input, Qe = (n / t1) x (3600 / k) kW
4. Compressor input, W = (n / t2) x (3600 / k) kW

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5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1
6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)
7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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57 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

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Sl.
No.

Initial
Temp.

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of water

Final
Temp.
of water

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Duration
of exp.

Delivery
pressure

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Delivery
Temp.

Condense

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Outlet
Pressure

Condense
Outlet

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Temp.


Pressure
after

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throttling

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Temp.
After
Throttli
ng

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Suction
pressur
e

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Suction
Temp.

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Time for
10 rev. of
compress
or energy

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meter



Height

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of water
in the
vessel

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58 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
Load Test with Capillary tube as expansion device:
1. Fill the chilled water calorimeter with pure water so that the evaporative coils are
fully immersed.
2. Select the capillary tube line by opening the shut-off valve on this line and closing

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the one on the thermostatic expansion valve line. The solenoid switch is switched OFF.
3. Start the compressor and run for some time so that the chilled water temperature
is lowered to the given test temperature.
4. Switch on the heater and slowly increase the power.
5. Allow The temperature in water calorimeter to reach the equilibrium

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temperature.
6. Connect energy meter to motor and heater by the selector switch one after another
and note down the time taken for 10 pulses of the energy meter disc.
7. Note down the pressure and temperature readings at locations 1,2,3 & 4 as
mentioned.

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8. Switch OFF the heater and the mains.
Result:
The load test on a refrigeration test rig was conducted and the results are as follows.
1. Actual C.O.P. of the system =____________.
2. Rhetorical C.O.P. of the system = ___________.

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3. Volumetric Efficiency = ___________.

Outcome:
From this experiment, conducting the load test on a refrigeration test rig and finding out the
volumetric efficiency and co-efficient of performance for any type of refrigerant is learnt and this experiment

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could be used in the areas such as Refrigerator and Air Conditioning.
Applications:
Refrigerator, Air Conditioning.

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59 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? COP
2. Which thermodynamic cycle is used in air conditioning of airplanes using air as refrigerant?
3. Define ? Ton of Refrigeration
4. What is meant by refrigeration?

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5. What is meant by air conditioning?
6. What are the four important properties of a good refrigerant?
7. How does the actual vapour compression cycle differ from that of the ideal cycle?
8. Name any four commonly used refrigerants.
9. What are the expansion devices used in a vapour compression plant?

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10. Why throttle valve is used in place of expansion cylinder for vapour compression refrigerant machine?
11. What are the merits of air refrigeration system?
12. What are the demerits of air refrigeration system?
13. Define ? Refrigerant
14. What is net refrigerating effect of the refrigerant?

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15. What are the methods to obtain sub cooling of refrigerant?

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Viva ? voce

60 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.12 EXPERIMENTS ON PSYCHROMETRIC PROCESS

Aim:
To conduct an experiment on psychrometric processes with air conditioning system

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Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Digital anemometer

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(v) Experimental setup
Description:
The test rig consist of
1. An air duct support of stand
2. A blower to set up air flow through the duct along with a speed control to vary the

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velocity of air.
3. A heater to rise the air temperature with regulator and energy meter.
4. Water spray, collecting tray, reservoir with gauge pump.
5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.
(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after cooling coil).

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6. The test rig consist of compressor, condenser unit placed inside trolley and fitted
with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for
condenser and (iv) Liquid receiver.
7. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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61 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I

Precautions:

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1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence
avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kw only for the motor
circuit.
2. Natural air currents in the room if in the direction of air duct may defect the experimental results and
hence the duct should be placed such that no wind from doors, windows, fan and cooling air from

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other test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan
and should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase
beyond 240 psi.
3. Never exceed dry bulb temperatures of 40
0

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C after the heater (station 2) otherwise the air duct may be
damaged.
4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may
exceed its maximum of 32
0

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C and calibration may be affected.
5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not
running this will lead to rise in temperature at the heater and may damage the heater and the air duct.
6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their
duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.

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7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer
is placed inside the reservoir at the top. This may have to the cleaned when necessary.
8. Do not open the gate valve fully otherwise water may be splashed outside and the waster
measurement may be in error.
S.

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N
o
Inlet temp
Outlet
temp

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Pressu
re
P1
Tem
p.

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T1
Pressu
re
P2
Temp.

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T2
Pressu
re
P3

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Tem
p.
T3

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Pressu
re
P4

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Temp.
T4
Energy
for 10
revolutio

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ns
Twet Tdry Twet Tdry Lb/in
o
C Lb/in
o

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C Lb/in
o
C Lb/in
o
C

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62 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

9. If the low pressure cut out comes in to action, it means that the Freon charge is insufficient and may

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have to be filled up. The suction pressure should never go below 2 psi as otherwise the compressor
seals will be damaged and air and moisture may enter the system.
10. The refrigerant strainer placed on the front panel should always be warm. If it cools and moisture
condenser on it, then the strainer might have to be charged by an experienced refrigeration
mechanics.

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11. The refrigerating system can work continuously for 2 hours, however if the room temperature is above
25
0
C the condenser may be heated up and the delivery pressure may rise. Do not exceed 240 psi.
Pour one or two glasses of drinking water over the fins of the condenser in order to reduce the

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delivery pressure.
12. After some months of operation the compressor may have to be topped up with oil and some quantity
of Freon-22 may have to be charged by an experienced mechanics.
13. See that distilled water is filled up in the plastic dishes provided under the wet bulb thermometers and
that the wicks are in tact otherwise erroneous readings may be obtained. These thermometers will

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show correct readings only when the fan is in operation.
14. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

Formulae used:

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1. Corresponding to the dry and wet bulb temperature at all the stations obtain the specific enthalpy and
specific humidity values from psychrometric chart.
i.e., h1 and w1 at tb1 and tw1 and so on.
2. Air flow rate, ma = (A x V) / v4 Kg / sec
Where, A = Area of duct at outlet in m

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2
(0.46 m x 0.086 m)
V = Air velocity ( m / sec)
V4 = Specific volume of moist air at station 4 using psychometric chart m
3

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/Kg
3. Moisture added from psychrometric chart, mw1 = ma (w3-w2) Kg / sec.
Where, w3 = Specific humidity at station 3
w2 = Specific humidity at station 2
4. Cooling effect produced on air, Qe = ma (h3 ? h4) kW.

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Where, h3 = Specific enthalpy at state 3 kJ/kg
h4 = Specific enthalpy at state 4 kJ/kg
5. Moisture condensed, mcl = ma (w3 ? w4) kg/sec
Where, w3 = Specific humidity at station 3
w4 = Specific humidity at station 4

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63 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Fill water in the wet bulb temperature probe trays.

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2. Start the main.
3. Start the blower and run it the required speed by keeping the speed regulator at
position.
4. Start the spray pump and open the gate valve suitably.
5. Start the heater.

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6. Select the expansion device (Capillary tube / Thermostatic expansion valve)
7. Start the cooling compressor.
8. Wait for some time till thermometers shown practically constant readings and note down the
following readings:
(i) Dry bulb temperatures tdb1, tdb2, tdb3, tdb4.

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(ii) Wet bulb temperatures twb1, twb2, twb3, twb4.
(iii) Spray water temperature, ts
(iv) Surface temperature of cooler, tm ( at control panel)
(v) Pressure gauge reading, pd ( at control panel)
(vi) Compound gauge reading, Ps ( at control panel)

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(vii) Level reduction?l? in spray reservoir (mm) during 5 min.
(viii) Amount of condensate collected ?lc?, in a measuring jar at cooler tray during a
run of 5 minutes at constant conditions.
(ix) Time in second ?SH? for 10 pulses of the energy meter disc connected to the
heater.

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(x) Time in seconds Sc for 10 pulses of the energy meter disc connected to cooler
compressor.
Result:
Experiment on psychrometric processes with air conditioning system was drawn
Outcome:

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From this experiment, conducting the test on psychrometric processes with air
conditioning system is learnt and this experiment could be used in all types of air conditioning systems.

Applications:
Air Conditioning.

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64 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the commonly used unit of refrigeration?
2. Distinguish between summer air conditioning and winter air conditioning.
3. Define ? RSHF Line

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4. Define ? By Pass Factor of a Heating Coil
5. What is the effect of sub cooling a refrigerant in a vapour compression cycle?
6. What is the function of analyzer and rectifier in an absorption system?
7. What is the purpose of generator assembly in vapour absorption refrigeration system?
8. State the substance used in the Lithium Bromide system and their functions.

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9. Differentiate wet compression from dry compression.
10. Define ? Apparatus Dew Point
11. What is meant by dew point temperature?
12. Define ? Wet Bulb Temperature
13. Define ? Degree of Saturation

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14. What is meant by specific humidity?
15. Define ? Relative Humidity

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Viva ? voce

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65 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.13

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PERFORMANCE TEST ON A RECIPROCATING
AIR COMPRESSOR

Aim:
To conduct a load test on the 2 - stage reciprocating air compressor to determine the isothermal and

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volumetric Efficiencies at various delivery pressures

Apparatus required:
* Air compressor with accessories.
* Stop watch.

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Description:
Two stage air compressors is a reciprocating type driven by a prime mover. The test rig consist of a base on
which the tank is mounted. The outlet of the compressor is connected to the receiver. The suction is
connected to air tank with a calibrated orifice plate through a water manometer. The input to the motor is
recorded by an energy meter. The temperature and pressure of the air compressed is indicated by a

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thermometer and pressure gauge.
Specifications:
1. Air compressor:
* LP Bore, DLP = 63.0 mm.
* HP Bore, DHP = 79.0 mm.

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* Stroke, L = 80.0 mm.
* Speed, N = 1440 rpm (5 HP)
* Effective radius = 0.193 m
2. Air receiver capacity = 0.33 m3
3. Orifice, diameter, d0 = 12 mm

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4. Orifice area,. A0 : ?d0
2
/ 4 = ----------- m
2

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5. Coefficient of discharge C d. = 0.6
6. Energy-meter constant = 200 rev / kWh

66 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I

Observation Table: II
Sl.
No.

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Actual
Discharge
Va
Theoritical
Discharge

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Vt
Volumetric
Efficiency
?
Power

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Input

Output
Power

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Overall
Efficiency
?0
Isothermal
Workdone

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IwD
Polytropic
Workdone
PwD
Isothermal

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Efficiency
?iso
m
3
/sec m

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3
/sec % kW kW % J/Kg J/Kg %


Sl.

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No.
Pressure
p
Manometer
h1

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Manometer
h2
Time for 5 revolutions Energy meter Speed of the compressor Temperature
T1
Temperature

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T1
Kg/cm
2
Cm cm sec rpm
o

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C
o
C

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67 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Check whether manometer is filled with water up to the required level.

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2. The maximum pressure in the receiver tank should not exceed 12 kg / cm
2

Procedure:
1. Ensure that gauge pressure in the tank is zero.

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2. Start the compressor. Read the receiver pressure gauge for a particular pressure.
3. Maintain the pressure constant by adjusting the outlet valve.
4. Note down the manometer reading and time taken for 3 revolution of the energy
Formulae used:
1. Density of air at RTP:

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? RTP = ? NTP X 273 Kg/ m
3

(273 + Room Temp)
Where density of air at NTP = 1.293 Kg/ m

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3
.

2. Air head causing flow:
ha RTP = (h1 - h2) x ? water m

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?a RTP
Where,
(h1- h2) = Difference in manometer liquid, in m.

3. Actual volume at RTP:

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Va RTP = C.d x Ao x ? 2 g ha RTP
Where,
C d= Coefficient of discharge = 0.6.
A o = Area of orifice = ?(d0)
2

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m
2
.
4
Diameter of orifice d o = 0.01 m.

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4. Actual volume at NTP:
Va NTP = VaRTP x T NTP
T RTP
Where,
T NTP = Normal temp - 273

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o
k
T RTP = Room temp -
o
c (273 + TROOM )

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5. Theoretical Volume of air: (at intake conditions)
V T = ?D

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2
x L x Nc m
3
/ sec.
4 x 60

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D = LP Bore diameter = 88.5 mm.
L = Stroke length = 88.9 mm.
Nc = Compressor speed rpm.
6. Volumetric Efficiency:(for LP stage)
?vol = Va NTP x 100%

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Vt
7. Shaft Input through Energy meter:

= 1 x n x ?t x ?m x 3600 kw.
( Ec x t )

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Where,
Ec = Energy meter constant = 200 rev / kWh
?t = Efficiency for transmission = 0.95.
? m = Efficiency for motor = 0.90.
t = Time for 'n' revolution of energy meter disc.

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n = no. of rev. of Energy meter disc.

8. Isothermal power:
= Pa x Va RTP x log e (R) W
1000

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Pa = Atmospheric pressure in N/ m
2
= 1.01325 x 10
5
N / m

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2
.
R = (Pressure gauge reading + atmospheric pressure)
atmospheric pressure.
9. Isothermal efficiency:

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? ISO = Isothermal power x 100%
Shaft input

Result:
The values of isothermal and volumetric efficiency at various delivery pressures have been studied &

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graph between Pressure Vs Volumetric efficiency and Pressure Vs Isothermal efficiency are drawn.


69 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Outcome:
From this experiment, conducting the load test on two stage reciprocating air compressor for
determining the isothermal and volumetric Efficiencies at various delivery pressures is understood and this
experiment could be used in the areas such as Refrigerator, Air Conditioning, IC engines, etc.

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Applications:
Refrigerator, Air Conditioning, IC engines.


1. How are air compressors classified?

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2. Define ? Isothermal Efficiency of Air Compressor
3. What is meant by FAD (Free Air Delivery)?
4. What is meant by perfect inter-cooling?
5. Define ? Clearance Ratio of an Air Compressor
6. List out the applications of compressed air.

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7. What are the types of air compressors?
8. What is meant by single acting compressor?
9. What is meant by double acting compressor?
10. What is meant by single stage compressor?
11. What is meant by multi stage compressor?

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12. Indicate the applications of reciprocating compressors in industry>
13. Define ? Mechanical Efficiency
14. What is meant by compression ratio?
15. What are the factors that affect the volumetric efficiency of a reciprocating compressor?

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Viva ? voce

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70 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.14

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PERFORMANCE TEST IN A HC REFRIGERATION
SYSTEM

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Aim:

To conduct the performance test on Vapour Compression Refrigeration System and to determine the
Coefficient of Performance using solenoid valve by throttling method

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Description:

In this system the working fluid is a HC out of a refrigeration system. The HC compression system is most
important system from the view point of commercial and domestic utility. The HC refrigerant at low temp and
pressure enters the reciprocating compressor, where it is compressed isentropically and subsequently its temp

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and pressure increases considerably. This HC after leaving the compressor enters the condenser where it is
cooled into low temperature. Then it is sucked by reciprocating compressor and is thus repeated.
Formula used:

Actual COP = refrigerant effect

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I/p energy to compressor
Refrigerant effect = mxCpx ? T
t
m - mass of water (kg)
Cp - Sp. Heat of water (4.2 kJ/kg K)

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?T ? decrease in temp (Ti-Ts)
t - timetaken duration of expt (sec)

Energy input =n x 3600 /k x t
n ? number of revolutions in energy meter

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t ? time taken of ?n? revolutions
k ? energy meter constant (3200)


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Tabulation:

Pressure of the refrigerant (Mpa) Temperature Time for n?
rev of

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energy
meter in
sec
P1 P2 P3 P4 Circulating fluid
temp

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Refrigerant temp

Ti Tf T1 T2 T3 T4

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72 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Model calculation:

Actual COP = refrigerant effect
I/p energy to compressor

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Refrigerant effect = mxCpx ? T
t
m - mass of water (kg)
Cp - Sp. Heat of water (4.2 kJ/kg K)

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?T ? decrease in temp (Ti-Ts)
t - time taken duration of experiment (sec)
Refrigerating effect = 8x4.2x (27-6)/1200=0.588 kw

Energy input = n x 3600

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n ? Number of revolutions in energy meter
t ? Time taken of ?n? revolutions
k ? Energy meter constant
=3 x 3600/(1200 x 54)
=0.166 kW

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Actual COP = refrigerant effect
I/p energy to compressor
= 0.588/0.166
=3.526
Result:

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The experiment was conducted successfully and coefficient of performance was found out is _______.

Outcome:
From this experiment, conducting the performance test on Vapour Compression Refrigeration

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System and to determine the Coefficient of Performance using solenoid valve by throttling method is
understood and this experiment could be used in the areas such as Refrigerator and Air Conditioning systems.
Applications:
Refrigerator, Air Conditioning.

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73 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the difference between air conditioning and refrigeration?

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2. Write any three important properties of a good refrigerant.
3. What is the function of analyzer and rectifier in an absorption system?
4. How does humidity affect human comfort?
5. What is the commonly used unit of refrigeration?
6. Distinguish between summer air conditioning and winter air conditioning.

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7. Define ? RSHF Line
8. Define ? By Pass Factor of a Heating Coil
9. What is the effect of sub cooling a refrigerant in a vapour compression cycle?
10. What is the function of analyzer and rectifier in an absorption system?
11. What is the purpose of generator assembly in vapour absorption refrigeration system?

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12. State the substance used in the Lithium Bromide system and their functions.
13. Differentiate wet compression from dry compression.
14. Define ? Apparatus Dew Point
15. What is meant by dew point temperature?
16. Define ? Wet Bulb Temperature

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17. Define ? Degree of Saturation
18. What is meant by specific humidity?
19. Define ? Relative Humidity
20. What is meant by dew point temperature?

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Viva ? voce

74 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.15

PERFORMANCE TEST IN A FLUIDIZED BED
COOLING SYSTEM

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Aim:
To determine the performance test on cooling tower
Introduction:
The cooling tower is one of the most important device in chemical industries for example when the hot
water come from heat exchanger we use the cooling tower to cool it The purpose of cooling tower is to cool

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relatively warm water by contacting with unsaturated air. The evaporation of water mainly provides cooling. In
typical water cooling water tower warm water flows countercurrent to an airstream. Typically, the warm water
enters the top of the packed tower and cascades down through the packing , leaving at the bottom Air enters
at the bottom of the tower and flows upward through the descending water . The tower packing often consist of
slats of plastic or of packed bed. The water is distributed by troughs and overflows to cascade over slat

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gratings or packing that provides large interfacial areas of contact between the water and air in the form of
droplets and films of water. The flow of air upward through the tower can be induced by the buoyancy of the
warm air in the tower (natural draft) or by the action of a fan . The water cannot be cooled below the wet bulb
temperature. The driving force for the evaporation of water is approximately the vapour pressure of the water
less the vapour pressure it would have at the wet bulb temperature

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Procedure:
1. Introduce water and record its flow rate.
2. Switch ON the heaters on so that water is heated to the required temperature.
3. Introduce air and record its flow rate.
4. Wait for steady state then record steady state dry and wet bulb temperature of air at the entrance and

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exit.
5. Record the inlet and outlet temperature and flow rate of water also record temperature at different
stages.
Tabulation:

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Sl.No. T1 (
0
c) T2 (
0
c) T3 (

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0
c) Efficiency

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T1 = room temperature

75 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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T2 = water inlet
T3 = water outlet

Efficiency of cooling tower

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ECT = T3/T2/*100

Model calculation:

Efficiency of cooling tower = water outlet

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--------------- *100
Water inlet

= 36/40 *100

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= 90
Result:
The performance test in cooling tower is determined as ______%.
Outcome:
From this experiment, conducting the performance test on cooling tower is understood and this

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experiment could be used in various power plants where cooling tower is used.
Applications:
Power Plant Cooling Tower, Cooling Tower.

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1. What are functions of a draught system?
2. What are the advantages of burning coal in pulverized form?
3. What are the functions of cooling tower?
4. What are the different types of draught system?
5. What are the methods used for handling of coal?

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6. What is meant by fluidized bed combustion?
7. What is the use of fluidized bed boiler?
8. What are the types of fluidized bed boiler?
9. State the purpose of condenser in fluidized bed boiler.
10. What is meant by pulveriser and why it is used?

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11. State the disadvantages of pulverized coal firing.
12. Distinguish between fouling and slagging.
Viva ? voce

76 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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ADDITIONAL EXPERIMENTS
BEYOND THE SYLLABUS

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77 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.16 AIR CONDITIONING TEST RIG

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Aim:
To conduct a performance test on air conditioning test rig and determine the Coefficient of Performance of
air conditioning system
Apparatus required:
(i) Thermometer

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(ii) Electric Heater
(iii) Stop watch
(iv) Digital anemometer
(v) Experimental setup
Description:

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The test rig consist of
1. An air duct support of stand
2. A blower to set up air flow through the duct along with a speed control to vary the
velocity of air.
3. A heater to rise the air temperature with regulator and energy meter.

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4. Water spray, collecting tray, reservoir with gauge pump.
5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.
(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after
cooling coil).
6. The test rig consists of compressor, condenser unit placed inside trolley and fitted

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with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan
for condenser and (iv) Liquid receiver.

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78 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I

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Air conditioning Test Rig

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Sl.
No

Inlet
temperat

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ure

Outlet
temperatu
re

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Pressu
re
P1

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Tem
p.
T1

Pressu

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re
P2
Temp.
T2

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Pressu
re
P3

Tem

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p.
T3


Pressu

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re
P4


Tem

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p.
T4

Energy for
10

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revolutions
Twet Tdry Twet Tdry Lb/in
o
C Lb/in
o

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C Lb/in
o
C
Lb/in
o

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C


FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart

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and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION

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VISION
MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence

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To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design

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products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies

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5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering

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2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools

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6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms

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9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder

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4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant

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9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system

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12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection

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experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.

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12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC

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Boiler.



COURSE OBJECTIVES

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COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS

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1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11

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3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21

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5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31

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7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47

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CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14

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Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate

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method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters

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together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples

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No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2

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(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help

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of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:

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1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm

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6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100

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0
C
9. Maximum temperature of the hot plate = 170
0
C

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10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V

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15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0

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C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:
Sl. No. Voltmeter
V

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Ammeter
A
Main heater (
0
C) Test Plate (

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0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:

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1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single

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phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.

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8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.

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3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?

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8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?

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13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?

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18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:

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To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple

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(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.

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There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.

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4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.

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4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging

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k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:

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Sl.
No.
Voltage
(V)
Current

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(A)
Heater Temperature
(
0
C)

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Asbestos Temperature
(
0
C)
Saw dust

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Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos

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layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:

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The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)

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6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?

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11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.

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16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical

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tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which

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in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.

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The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Schematic view of the test set-up:

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mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch

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Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples

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6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}

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Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W

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Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L
3

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?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v
2

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is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid

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v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity

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?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.

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hL / k = 0.56 (Gr.Pr)
0.25
for 10
4
< Gr.Pr.<10

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8

hL / k = 0.13 (Gr.Pr)
1/3
for 10

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8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).

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3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:

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The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m

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2
K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing

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heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?

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5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)

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10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness

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15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?

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20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:

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To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer

Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air

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stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of

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orifice meter and the water manometer fitted on the board.


24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

Sl. No. Voltage Current Temperature in (

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0
C)
Manometer
reading of water
in h in meter

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(V) (A)
T1

T2

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T3

T4

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T5

T6

h1

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cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor

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5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0
C

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(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:

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1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.

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6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.

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2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. The rate at which air is getting heated is calculated as

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qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o

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C)
= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate

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Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m
3
/hr

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3. ha = qa /A(Ts- Ta) W / m
2
K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m

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2

Ta = Average temperature of air = (T1 + T6)/2
o
C

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Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C
Cd = 0.64
H = Difference of water level in manometer m

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?w Density of water = 1000 Kg/m
3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

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d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

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using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2

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)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o
C

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5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

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27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k

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? = Viscosity Ns/m
2

k = Thermal conductivity of fluid W/m
2

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K
Nu = 0.023 (Re)
0.8
(Pr)
0.4

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Bulk mean temperature = (T1 + T6)/2

Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.

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hactual = -------------- W/m
2
K
htheoritical = -------------- W/m
2

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K

Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?

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3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?

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8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection

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13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

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Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,

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the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure

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temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat

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flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm

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2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.

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2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

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30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature

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gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:

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Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R

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Tabulation:
Sl.No. Voltmeter
reading
(V)
Ammeter

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reading
(A)
T1
(
0

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C)
T2
(
0
C)

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T3
(
0
C)
T4

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(
0
C)
T5
(

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0
C)
T6
(
0

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C)
T7
(
0
C)

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T8
(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Composite wall apparatus set-up

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Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W

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c. Asbestos section = ------------W

Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure

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Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?

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5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.

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9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

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33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

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DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

Aim:
To find out the thermal conductivity of insulating powder by conduction

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Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A

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multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

Procedure:

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1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.

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5. Repeat the experiments for different power inputs.


The readings are tabulated below

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Sl.No. Voltmeter
reading( V)
Ammeter
reading (A)
T1

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(
0
C)
T2
(

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0
C)
T3
(
0

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C)
T4
(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm

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The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Fig. 1 Apparatus of thermal conductivity of insulating powder

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[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

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Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam

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boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity

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3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.

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8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?

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13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?

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18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

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HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

Aim:

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To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is

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measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:
Sl.

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No.
V I

Fin Temperatures (
0

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C)
Ambient Temp
(
0
C)

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Manometer
Reading
(V)

(A)

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T1 T2 T3 T4 T5 T6 T7 T8
h1
cm
h2

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cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Duct size = 150 mm x 100 mm.

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2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

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Schematic view of the test set-up:



zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5

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10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C
12. Temperature indicator = 0 ? 300

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0
C
(With compensation of ambient temperature up-to 50
0
C)

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13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8

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Brass Pin Fin
Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.

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4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:

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Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.

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4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2

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Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m

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3
/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m

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3

?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s

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2

Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s

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Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

A = area of the duct

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4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.

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(T1 + T6) / 2
o
C
5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number

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6. Nusselt Number:
Nu = CRe
m
(Pr)
0.33

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7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk
m= ?(hp/kA)

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A = area of fin = (? x D
2
) /4
L = Length of the fin
Tw ? average temperature

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T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________

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Heat transfer, Q = ___________ W

Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.


40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer

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6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?

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11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.8

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DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

Aim:

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To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch

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(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water

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between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.

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When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere

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3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg

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8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C
= (or) 0.1 Kcal / kg
0

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C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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11. Temperature indicator digital 0.1
0
C L.C 0 - 200
0

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C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water
Precautions:

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Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4

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? Td
4
)
Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)

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Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

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43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulations:
Proc
edur

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e:
1. H
eat the
water
in the

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tank by
the immersion heater up to a temperature of about 90
0
C.
2. Remove the disc, D before pouring the hot water in the jacket.

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3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.

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6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m

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2
k
4
.

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Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using

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boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

Sl. No.

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Hemisphere Temperature(
0
C) Avg. Temp.
of the
Hemisphere

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(Th)
T4
Steady
Temp. of
Disc

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T0 (Td)
Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number
5. State Wien?s displacement law.

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6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation
10. What are the various modes of condensation?

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11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.9

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DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

Aim:

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To measure emissivity of the test plate surface at various temperature
Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The

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temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.
Specifications:
1. Heater input to black plate W1 = V1 x I1 W

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2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V

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6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300

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0
C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.

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Tabulation:
Sl.
No
Voltage

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Current

Black body
temp(
0

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C)
Avg.
temp.

Polished body

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temp (
0
C)
Avg.
temp.

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Enclosure
Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts

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4
? Ta
4
) A
Eb ? E = (W1 ? W2) / ? (Ts

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4
? Ta
4
) A
E = Eb ? {(W1 ? W2) / ? (Ts

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4
? Ta
4
) A}
Where,

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W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd
2
m

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2

T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)

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Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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? = Stefan boltzman constant = 5.67 x 10
-8
W/m
2
K

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4


Schematic view of the test set-up:

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Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by

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the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

Results:

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The emissivity of the test plate surface is found to be _____________.
Outcome:
From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

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48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Emissivity
2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?

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4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?
6. What is meant by shape factor?
7. Define ? Radiation
8. What is meant by monochromatic emissive power?

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9. Define ? Emissive Power
10. What is meant by absorptivity?
11. Define ? Black Body
12. What is meant by transmissivity?
13. State Plank's distribution law

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14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

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49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.10

EFFECTIVENESS OF PARALLEL / COUNTER

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FLOW HEAT EXCHANGE

Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:

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(i) Experimental Setup
(ii) Stop watch
(iii) Thermometer
Theory:
Heat exchangers are classified in three categories:

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1. Transfer type
2. Storage type
3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.

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The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water

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which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:

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1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50

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0
C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100
0
C - 2 Nos.

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7. Measuring flask = 0 ? 1000 CC

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8. Geyser: single phase type to obtain hot water supply

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9. Thermo Cole insulation for outer pipe.
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Tabulations:

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Sl.
No.
Flow Hot Fluid (
0
C) Cold Fluid (

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0
C)
Time for
collection of
hot fluid

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Kg/sec
Time for
collection
of cold fluid
Kg/sec

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1 Parallel flow
Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)

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1. Area of the pipe A = ? (D ? d) L
Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube
L = Length of the tube

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2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

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Where, m = mass flow rate Kg/ sec.

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m = ?v/t, ? = density of water and t = time taken for hot water
Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet
Tho = Temperature of hot water outlet

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3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W
Where, m = mass flow rate
Cp = Specific heat of capacity
Tco = Temperature of cold water inlet
Tci = Temperature of cold water outlet

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4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W
Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)
?Tm = (?Ti - ?To) / In (?Ti/?To)
Where, ?To = Tho ? Tco

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?Ti = Thi ? Tci
6. Over all heat transfer coefficient
h = Q?/?Tm A W/m
2
K

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where Q? = (Qa + Qc) / 2

Procedure:
1. Place the thermometers in position and note down their readings when they are at room temperature and
no water is flowing at either side. This is required to correct the temperature.

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2. Start the flow on hot water side.
3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.
5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.
6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.

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7. Keeping the flow rates same, wait till the steady state conditions are reached.
8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.
10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

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52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Result:
1. The values of effectiveness of heat exchanger were found as

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(i) Parallel flow = ________.
(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)
(i) Parallel flow = ________.
(ii) Counter flow = _________.

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Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow
heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat
exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Heat Exchanger
2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?
4. Write about the merits of drop wise condensation.
5. What is meant by film wise and drop wise condensation?

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6. What is meant by effectiveness?
7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?
9. Distinguish between regenerator and recuperates.
10. What is meant by parallel flow heat exchanger?

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11. What is meant by counter flow heat exchanger?
12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?
Viva ? voce

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53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.11

DETERMINATION OF COP OF A REFRIGERATION

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SYSTEM

Aim:
To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration
system

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Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Experimental setup

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Description:
1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a
reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.
2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated
wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a

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low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the
temperature of chilled water. The above unit is located on the trolley behind front panel.
3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic
expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum
strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure

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gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high
pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy
meter to measure the power consumed either by hater or by compressor.

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54 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
A. A compressor condenser unit placed inside trolley and fitted with
1. R-134a reciprocating compressor
2. Condenser

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3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan
4. A receiver with angle check valve
B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity
placed inside a well insulated wooden box and provided with
5. Evaporator coil

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6. Stirrer
7. Electric heater 230 V, A.C.
8. The sensing bulb of low temperature thermostat.
9. A high temperature thermostat.
10. A Thermometer to measure the chilled water temperature

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C. The front panel on which are mounted the following
11. Capillary expansion tube with isolating valve.
12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator
and isolating valve
13. Drier cum strainer and sight glass

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14. Thermostat at inlet and outlet of both evaporator and condenser
15. Pressure gauge at inlet and outlet of evaporator and condenser
16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out
17. Heat power regulator switch and regulator
18. Energy meter to measure the power consumed either by hater or by compressor.

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55 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.
2. The heater regulator should be switched off whenever not in use. Heating water beyond 40
0
C may lead to

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permanent damage of the entire system. A high temperature cut off thermostat is provided in the water
chiller, to cut off the heater beyond 30
0
C.Check the setting of the same before operation.
3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.

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4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.
5. The solenoid thermostat is adjusted to cut at 15
0
C and cut in at 10
0

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C of the chilled water. Do not alter the
same.
6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.
7. The space near the condenser should permit good ventilation to aid proper fan performance.
8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked

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in
0
F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,
calibrated in SI units, are not available.)
9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to

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obtain the pressure in MN/m
2
.e.g. P = x psig
= (x + 14.7) psia
= (x + 14.7) / 145 MN/m

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2
(MPa)
10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.
Formulae used:
Let, State 1 indicates the entry of compressor.

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State 2 indicates the exit of compressor.
State 3 indicates the exit from condenser.
State 4 indicates the entry to evaporator
P = Pressure (bar)
T = Temperature (

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0
C)
H = Specific enthalpy (kJ/kg)
v = Specific Volume (m
3

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/Kg)
n = Number of revolutions of energy meter disc.
t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)
t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)
K = Energy meter constant = 3200 lmp / kWh

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N = Speed of compressor = 2840 rpm
h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

56 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2
h3 = Specific enthalpy at Pc and T3 (kJ/kg)
h4 = h3
Stroke volume of compressor = (?/ 4) d
2

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l = 12.58 x 10
-6
m
3

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1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar
2. Average condenser pressure, Pc = (P2 + P3) / 2 bar
3. Heater input, Qe = (n / t1) x (3600 / k) kW
4. Compressor input, W = (n / t2) x (3600 / k) kW
5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1

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6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)
7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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57 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I


Sl.

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No.

Initial
Temp.
of water

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Final
Temp.
of water
Duration

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of exp.

Delivery
pressure

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Delivery
Temp.

Condense
Outlet

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Pressure

Condense
Outlet
Temp.

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Pressure
after
throttling

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Temp.
After
Throttli
ng

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Suction
pressur
e
Suction

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Temp.

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Time for
10 rev. of
compress
or energy
meter

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Height
of water

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in the
vessel

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58 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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Load Test with Capillary tube as expansion device:
1. Fill the chilled water calorimeter with pure water so that the evaporative coils are
fully immersed.
2. Select the capillary tube line by opening the shut-off valve on this line and closing
the one on the thermostatic expansion valve line. The solenoid switch is switched OFF.

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3. Start the compressor and run for some time so that the chilled water temperature
is lowered to the given test temperature.
4. Switch on the heater and slowly increase the power.
5. Allow The temperature in water calorimeter to reach the equilibrium
temperature.

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6. Connect energy meter to motor and heater by the selector switch one after another
and note down the time taken for 10 pulses of the energy meter disc.
7. Note down the pressure and temperature readings at locations 1,2,3 & 4 as
mentioned.
8. Switch OFF the heater and the mains.

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Result:
The load test on a refrigeration test rig was conducted and the results are as follows.
1. Actual C.O.P. of the system =____________.
2. Rhetorical C.O.P. of the system = ___________.
3. Volumetric Efficiency = ___________.

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Outcome:
From this experiment, conducting the load test on a refrigeration test rig and finding out the
volumetric efficiency and co-efficient of performance for any type of refrigerant is learnt and this experiment
could be used in the areas such as Refrigerator and Air Conditioning.

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Applications:
Refrigerator, Air Conditioning.

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59 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? COP
2. Which thermodynamic cycle is used in air conditioning of airplanes using air as refrigerant?
3. Define ? Ton of Refrigeration
4. What is meant by refrigeration?
5. What is meant by air conditioning?

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6. What are the four important properties of a good refrigerant?
7. How does the actual vapour compression cycle differ from that of the ideal cycle?
8. Name any four commonly used refrigerants.
9. What are the expansion devices used in a vapour compression plant?
10. Why throttle valve is used in place of expansion cylinder for vapour compression refrigerant machine?

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11. What are the merits of air refrigeration system?
12. What are the demerits of air refrigeration system?
13. Define ? Refrigerant
14. What is net refrigerating effect of the refrigerant?
15. What are the methods to obtain sub cooling of refrigerant?

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Viva ? voce

60 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.12 EXPERIMENTS ON PSYCHROMETRIC PROCESS

Aim:
To conduct an experiment on psychrometric processes with air conditioning system
Apparatus required:

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(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Digital anemometer
(v) Experimental setup

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Description:
The test rig consist of
1. An air duct support of stand
2. A blower to set up air flow through the duct along with a speed control to vary the
velocity of air.

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3. A heater to rise the air temperature with regulator and energy meter.
4. Water spray, collecting tray, reservoir with gauge pump.
5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.
(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after cooling coil).
6. The test rig consist of compressor, condenser unit placed inside trolley and fitted

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with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for
condenser and (iv) Liquid receiver.
7. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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61 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I

Precautions:
1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence

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avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kw only for the motor
circuit.
2. Natural air currents in the room if in the direction of air duct may defect the experimental results and
hence the duct should be placed such that no wind from doors, windows, fan and cooling air from
other test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan

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and should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase
beyond 240 psi.
3. Never exceed dry bulb temperatures of 40
0
C after the heater (station 2) otherwise the air duct may be

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damaged.
4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may
exceed its maximum of 32
0
C and calibration may be affected.

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5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not
running this will lead to rise in temperature at the heater and may damage the heater and the air duct.
6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their
duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.
7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer

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is placed inside the reservoir at the top. This may have to the cleaned when necessary.
8. Do not open the gate valve fully otherwise water may be splashed outside and the waster
measurement may be in error.
S.
N

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o
Inlet temp
Outlet
temp
Pressu

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re
P1
Tem
p.
T1

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Pressu
re
P2
Temp.
T2

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Pressu
re
P3

Tem

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p.
T3


Pressu

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re
P4


Temp.

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T4
Energy
for 10
revolutio
ns

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Twet Tdry Twet Tdry Lb/in
o
C Lb/in
o
C Lb/in

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o
C Lb/in
o
C

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62 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

9. If the low pressure cut out comes in to action, it means that the Freon charge is insufficient and may
have to be filled up. The suction pressure should never go below 2 psi as otherwise the compressor

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seals will be damaged and air and moisture may enter the system.
10. The refrigerant strainer placed on the front panel should always be warm. If it cools and moisture
condenser on it, then the strainer might have to be charged by an experienced refrigeration
mechanics.
11. The refrigerating system can work continuously for 2 hours, however if the room temperature is above

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25
0
C the condenser may be heated up and the delivery pressure may rise. Do not exceed 240 psi.
Pour one or two glasses of drinking water over the fins of the condenser in order to reduce the
delivery pressure.

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12. After some months of operation the compressor may have to be topped up with oil and some quantity
of Freon-22 may have to be charged by an experienced mechanics.
13. See that distilled water is filled up in the plastic dishes provided under the wet bulb thermometers and
that the wicks are in tact otherwise erroneous readings may be obtained. These thermometers will
show correct readings only when the fan is in operation.

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14. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

Formulae used:
1. Corresponding to the dry and wet bulb temperature at all the stations obtain the specific enthalpy and

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specific humidity values from psychrometric chart.
i.e., h1 and w1 at tb1 and tw1 and so on.
2. Air flow rate, ma = (A x V) / v4 Kg / sec
Where, A = Area of duct at outlet in m
2

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(0.46 m x 0.086 m)
V = Air velocity ( m / sec)
V4 = Specific volume of moist air at station 4 using psychometric chart m
3
/Kg

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3. Moisture added from psychrometric chart, mw1 = ma (w3-w2) Kg / sec.
Where, w3 = Specific humidity at station 3
w2 = Specific humidity at station 2
4. Cooling effect produced on air, Qe = ma (h3 ? h4) kW.
Where, h3 = Specific enthalpy at state 3 kJ/kg

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h4 = Specific enthalpy at state 4 kJ/kg
5. Moisture condensed, mcl = ma (w3 ? w4) kg/sec
Where, w3 = Specific humidity at station 3
w4 = Specific humidity at station 4

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63 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Fill water in the wet bulb temperature probe trays.
2. Start the main.

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3. Start the blower and run it the required speed by keeping the speed regulator at
position.
4. Start the spray pump and open the gate valve suitably.
5. Start the heater.
6. Select the expansion device (Capillary tube / Thermostatic expansion valve)

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7. Start the cooling compressor.
8. Wait for some time till thermometers shown practically constant readings and note down the
following readings:
(i) Dry bulb temperatures tdb1, tdb2, tdb3, tdb4.
(ii) Wet bulb temperatures twb1, twb2, twb3, twb4.

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(iii) Spray water temperature, ts
(iv) Surface temperature of cooler, tm ( at control panel)
(v) Pressure gauge reading, pd ( at control panel)
(vi) Compound gauge reading, Ps ( at control panel)
(vii) Level reduction?l? in spray reservoir (mm) during 5 min.

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(viii) Amount of condensate collected ?lc?, in a measuring jar at cooler tray during a
run of 5 minutes at constant conditions.
(ix) Time in second ?SH? for 10 pulses of the energy meter disc connected to the
heater.
(x) Time in seconds Sc for 10 pulses of the energy meter disc connected to cooler

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compressor.
Result:
Experiment on psychrometric processes with air conditioning system was drawn
Outcome:
From this experiment, conducting the test on psychrometric processes with air

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conditioning system is learnt and this experiment could be used in all types of air conditioning systems.

Applications:
Air Conditioning.

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64 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the commonly used unit of refrigeration?
2. Distinguish between summer air conditioning and winter air conditioning.
3. Define ? RSHF Line
4. Define ? By Pass Factor of a Heating Coil

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5. What is the effect of sub cooling a refrigerant in a vapour compression cycle?
6. What is the function of analyzer and rectifier in an absorption system?
7. What is the purpose of generator assembly in vapour absorption refrigeration system?
8. State the substance used in the Lithium Bromide system and their functions.
9. Differentiate wet compression from dry compression.

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10. Define ? Apparatus Dew Point
11. What is meant by dew point temperature?
12. Define ? Wet Bulb Temperature
13. Define ? Degree of Saturation
14. What is meant by specific humidity?

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15. Define ? Relative Humidity

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Viva ? voce

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65 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.13

PERFORMANCE TEST ON A RECIPROCATING

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AIR COMPRESSOR

Aim:
To conduct a load test on the 2 - stage reciprocating air compressor to determine the isothermal and
volumetric Efficiencies at various delivery pressures

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Apparatus required:
* Air compressor with accessories.
* Stop watch.
Description:

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Two stage air compressors is a reciprocating type driven by a prime mover. The test rig consist of a base on
which the tank is mounted. The outlet of the compressor is connected to the receiver. The suction is
connected to air tank with a calibrated orifice plate through a water manometer. The input to the motor is
recorded by an energy meter. The temperature and pressure of the air compressed is indicated by a
thermometer and pressure gauge.

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Specifications:
1. Air compressor:
* LP Bore, DLP = 63.0 mm.
* HP Bore, DHP = 79.0 mm.
* Stroke, L = 80.0 mm.

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* Speed, N = 1440 rpm (5 HP)
* Effective radius = 0.193 m
2. Air receiver capacity = 0.33 m3
3. Orifice, diameter, d0 = 12 mm
4. Orifice area,. A0 : ?d0

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2
/ 4 = ----------- m
2

5. Coefficient of discharge C d. = 0.6

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6. Energy-meter constant = 200 rev / kWh

66 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

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Observation Table: II
Sl.
No.
Actual

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Discharge
Va
Theoritical
Discharge
Vt

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Volumetric
Efficiency
?
Power
Input

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Output
Power

Overall

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Efficiency
?0
Isothermal
Workdone
IwD

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Polytropic
Workdone
PwD
Isothermal
Efficiency

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?iso
m
3
/sec m
3

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/sec % kW kW % J/Kg J/Kg %


Sl.
No.

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Pressure
p
Manometer
h1
Manometer

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h2
Time for 5 revolutions Energy meter Speed of the compressor Temperature
T1
Temperature
T1

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Kg/cm
2
Cm cm sec rpm
o
C

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o
C

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67 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Check whether manometer is filled with water up to the required level.
2. The maximum pressure in the receiver tank should not exceed 12 kg / cm

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2

Procedure:
1. Ensure that gauge pressure in the tank is zero.
2. Start the compressor. Read the receiver pressure gauge for a particular pressure.

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3. Maintain the pressure constant by adjusting the outlet valve.
4. Note down the manometer reading and time taken for 3 revolution of the energy
Formulae used:
1. Density of air at RTP:
? RTP = ? NTP X 273 Kg/ m

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3

(273 + Room Temp)
Where density of air at NTP = 1.293 Kg/ m
3

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.

2. Air head causing flow:
ha RTP = (h1 - h2) x ? water m
?a RTP

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Where,
(h1- h2) = Difference in manometer liquid, in m.

3. Actual volume at RTP:
Va RTP = C.d x Ao x ? 2 g ha RTP

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Where,
C d= Coefficient of discharge = 0.6.
A o = Area of orifice = ?(d0)
2
m

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2
.
4
Diameter of orifice d o = 0.01 m.
4. Actual volume at NTP:

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Va NTP = VaRTP x T NTP
T RTP
Where,
T NTP = Normal temp - 273
o

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k
T RTP = Room temp -
o
c (273 + TROOM )

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5. Theoretical Volume of air: (at intake conditions)
V T = ?D
2

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x L x Nc m
3
/ sec.
4 x 60
D = LP Bore diameter = 88.5 mm.

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L = Stroke length = 88.9 mm.
Nc = Compressor speed rpm.
6. Volumetric Efficiency:(for LP stage)
?vol = Va NTP x 100%
Vt

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7. Shaft Input through Energy meter:

= 1 x n x ?t x ?m x 3600 kw.
( Ec x t )
Where,

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Ec = Energy meter constant = 200 rev / kWh
?t = Efficiency for transmission = 0.95.
? m = Efficiency for motor = 0.90.
t = Time for 'n' revolution of energy meter disc.
n = no. of rev. of Energy meter disc.

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8. Isothermal power:
= Pa x Va RTP x log e (R) W
1000
Pa = Atmospheric pressure in N/ m

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2
= 1.01325 x 10
5
N / m
2

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.
R = (Pressure gauge reading + atmospheric pressure)
atmospheric pressure.
9. Isothermal efficiency:
? ISO = Isothermal power x 100%

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Shaft input

Result:
The values of isothermal and volumetric efficiency at various delivery pressures have been studied &
graph between Pressure Vs Volumetric efficiency and Pressure Vs Isothermal efficiency are drawn.

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69 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Outcome:

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From this experiment, conducting the load test on two stage reciprocating air compressor for
determining the isothermal and volumetric Efficiencies at various delivery pressures is understood and this
experiment could be used in the areas such as Refrigerator, Air Conditioning, IC engines, etc.

Applications:

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Refrigerator, Air Conditioning, IC engines.


1. How are air compressors classified?
2. Define ? Isothermal Efficiency of Air Compressor

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3. What is meant by FAD (Free Air Delivery)?
4. What is meant by perfect inter-cooling?
5. Define ? Clearance Ratio of an Air Compressor
6. List out the applications of compressed air.
7. What are the types of air compressors?

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8. What is meant by single acting compressor?
9. What is meant by double acting compressor?
10. What is meant by single stage compressor?
11. What is meant by multi stage compressor?
12. Indicate the applications of reciprocating compressors in industry>

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13. Define ? Mechanical Efficiency
14. What is meant by compression ratio?
15. What are the factors that affect the volumetric efficiency of a reciprocating compressor?

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Viva ? voce

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70 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.14

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PERFORMANCE TEST IN A HC REFRIGERATION
SYSTEM


Aim:

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To conduct the performance test on Vapour Compression Refrigeration System and to determine the
Coefficient of Performance using solenoid valve by throttling method

Description:

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In this system the working fluid is a HC out of a refrigeration system. The HC compression system is most
important system from the view point of commercial and domestic utility. The HC refrigerant at low temp and
pressure enters the reciprocating compressor, where it is compressed isentropically and subsequently its temp
and pressure increases considerably. This HC after leaving the compressor enters the condenser where it is

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cooled into low temperature. Then it is sucked by reciprocating compressor and is thus repeated.
Formula used:

Actual COP = refrigerant effect
I/p energy to compressor

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Refrigerant effect = mxCpx ? T
t
m - mass of water (kg)
Cp - Sp. Heat of water (4.2 kJ/kg K)
?T ? decrease in temp (Ti-Ts)

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t - timetaken duration of expt (sec)

Energy input =n x 3600 /k x t
n ? number of revolutions in energy meter
t ? time taken of ?n? revolutions

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k ? energy meter constant (3200)


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Tabulation:

Pressure of the refrigerant (Mpa) Temperature Time for n?
rev of
energy

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meter in
sec
P1 P2 P3 P4 Circulating fluid
temp
Refrigerant temp

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Ti Tf T1 T2 T3 T4

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Model calculation:

Actual COP = refrigerant effect
I/p energy to compressor

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Refrigerant effect = mxCpx ? T
t
m - mass of water (kg)
Cp - Sp. Heat of water (4.2 kJ/kg K)
?T ? decrease in temp (Ti-Ts)

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t - time taken duration of experiment (sec)
Refrigerating effect = 8x4.2x (27-6)/1200=0.588 kw

Energy input = n x 3600
n ? Number of revolutions in energy meter

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t ? Time taken of ?n? revolutions
k ? Energy meter constant
=3 x 3600/(1200 x 54)
=0.166 kW
Actual COP = refrigerant effect

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I/p energy to compressor
= 0.588/0.166
=3.526
Result:

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The experiment was conducted successfully and coefficient of performance was found out is _______.

Outcome:
From this experiment, conducting the performance test on Vapour Compression Refrigeration
System and to determine the Coefficient of Performance using solenoid valve by throttling method is

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understood and this experiment could be used in the areas such as Refrigerator and Air Conditioning systems.
Applications:
Refrigerator, Air Conditioning.

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1. What is the difference between air conditioning and refrigeration?
2. Write any three important properties of a good refrigerant.

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3. What is the function of analyzer and rectifier in an absorption system?
4. How does humidity affect human comfort?
5. What is the commonly used unit of refrigeration?
6. Distinguish between summer air conditioning and winter air conditioning.
7. Define ? RSHF Line

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8. Define ? By Pass Factor of a Heating Coil
9. What is the effect of sub cooling a refrigerant in a vapour compression cycle?
10. What is the function of analyzer and rectifier in an absorption system?
11. What is the purpose of generator assembly in vapour absorption refrigeration system?
12. State the substance used in the Lithium Bromide system and their functions.

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13. Differentiate wet compression from dry compression.
14. Define ? Apparatus Dew Point
15. What is meant by dew point temperature?
16. Define ? Wet Bulb Temperature
17. Define ? Degree of Saturation

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18. What is meant by specific humidity?
19. Define ? Relative Humidity
20. What is meant by dew point temperature?

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Viva ? voce

74 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.15

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PERFORMANCE TEST IN A FLUIDIZED BED
COOLING SYSTEM

Aim:

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To determine the performance test on cooling tower
Introduction:
The cooling tower is one of the most important device in chemical industries for example when the hot
water come from heat exchanger we use the cooling tower to cool it The purpose of cooling tower is to cool
relatively warm water by contacting with unsaturated air. The evaporation of water mainly provides cooling. In

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typical water cooling water tower warm water flows countercurrent to an airstream. Typically, the warm water
enters the top of the packed tower and cascades down through the packing , leaving at the bottom Air enters
at the bottom of the tower and flows upward through the descending water . The tower packing often consist of
slats of plastic or of packed bed. The water is distributed by troughs and overflows to cascade over slat
gratings or packing that provides large interfacial areas of contact between the water and air in the form of

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droplets and films of water. The flow of air upward through the tower can be induced by the buoyancy of the
warm air in the tower (natural draft) or by the action of a fan . The water cannot be cooled below the wet bulb
temperature. The driving force for the evaporation of water is approximately the vapour pressure of the water
less the vapour pressure it would have at the wet bulb temperature
Procedure:

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1. Introduce water and record its flow rate.
2. Switch ON the heaters on so that water is heated to the required temperature.
3. Introduce air and record its flow rate.
4. Wait for steady state then record steady state dry and wet bulb temperature of air at the entrance and
exit.

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5. Record the inlet and outlet temperature and flow rate of water also record temperature at different
stages.
Tabulation:

Sl.No. T1 (

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0
c) T2 (
0
c) T3 (
0

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c) Efficiency

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T1 = room temperature

75 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

T2 = water inlet

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T3 = water outlet

Efficiency of cooling tower

ECT = T3/T2/*100

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Model calculation:

Efficiency of cooling tower = water outlet
--------------- *100

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Water inlet

= 36/40 *100

= 90

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Result:
The performance test in cooling tower is determined as ______%.
Outcome:
From this experiment, conducting the performance test on cooling tower is understood and this
experiment could be used in various power plants where cooling tower is used.

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Applications:
Power Plant Cooling Tower, Cooling Tower.


1. What are functions of a draught system?

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2. What are the advantages of burning coal in pulverized form?
3. What are the functions of cooling tower?
4. What are the different types of draught system?
5. What are the methods used for handling of coal?
6. What is meant by fluidized bed combustion?

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7. What is the use of fluidized bed boiler?
8. What are the types of fluidized bed boiler?
9. State the purpose of condenser in fluidized bed boiler.
10. What is meant by pulveriser and why it is used?
11. State the disadvantages of pulverized coal firing.

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12. Distinguish between fouling and slagging.
Viva ? voce

76 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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ADDITIONAL EXPERIMENTS
BEYOND THE SYLLABUS

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77 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.16 AIR CONDITIONING TEST RIG

Aim:

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To conduct a performance test on air conditioning test rig and determine the Coefficient of Performance of
air conditioning system
Apparatus required:
(i) Thermometer
(ii) Electric Heater

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(iii) Stop watch
(iv) Digital anemometer
(v) Experimental setup
Description:
The test rig consist of

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1. An air duct support of stand
2. A blower to set up air flow through the duct along with a speed control to vary the
velocity of air.
3. A heater to rise the air temperature with regulator and energy meter.
4. Water spray, collecting tray, reservoir with gauge pump.

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5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.
(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after
cooling coil).
6. The test rig consists of compressor, condenser unit placed inside trolley and fitted
with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan

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for condenser and (iv) Liquid receiver.

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78 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

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Air conditioning Test Rig

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Sl.

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No

Inlet
temperat
ure

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Outlet
temperatu
re

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Pressu
re
P1

Tem

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p.
T1

Pressu
re

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P2
Temp.
T2

Pressu

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re
P3

Tem
p.

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T3


Pressu
re

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P4


Tem
p.

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T4

Energy for
10
revolutions

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Twet Tdry Twet Tdry Lb/in
o
C Lb/in
o
C Lb/in

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o
C
Lb/in
o
C

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Precautions:
1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence
avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kW only for the motor circuit.
2. Natural air currents in the room if in the direction of air duct may defect the experimental results and
hence the duct should be placed such that no wind from doors, windows, fan and cooling air from other

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test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan and
should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase beyond
240 psi.
3. Never exceed dry bulb temperatures of 40
0

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C after the heater (station 2) otherwise the air duct may be
damaged.
4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may
exceed its maximum of 32
0

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C and calibration may be affected.
5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not
running this will lead to rise in temperature at the heater and may damage the heater and the air duct.
6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their
duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.

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7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer is
placed inside the reservoir at the top. This may have to the cleaned when necessary.
8. Do not open the gate valve fully otherwise water may be splashed outside and the waster measurement
may be in error.
9. If the low pressure cut out comes in to action, it means that the Freon charge is insufficient and may have

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to be filled up. The suction pressure should never go below 2 psi as otherwise the compressor seals will
be damaged and air and moisture may enter the system.
10. The refrigerant strainer placed on the front panel should always be warm. If it cools and moisture
condenser on it, then the strainer might have to be charged by an experienced refrigeration mechanics.
11. The refrigerating system can work continuously for 2 hours, however if the room temperature is above

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25
0
C the condenser may be heated up and the delivery pressure may rise. Do not exceed 240 psi. Pour
one or two glasses of drinking water over the fins of the condenser in order to reduce the delivery
pressure.

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12. After some months of operation the compressor may have to be topped up with oil and some quantity of
Freon-22 may have to be charged by an experienced mechanics.

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FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________

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Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00


3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and

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enterprising professionals conforming to global standards through value based quality education and training.



? To provide competent technical manpower capable of meeting requirements of the industry

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? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING



Rendering the services to the global needs of engineering industries by educating students to become

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professionally sound mechanical engineers of excellent caliber



To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on

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experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION
MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould

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them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth

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To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up

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their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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PROGRAMME OUTCOMES (POs)

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On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications

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4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability

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8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills

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11. To develop and manage projects in multidisciplinary environments

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ME6512 ? THERMAL ENGINEERING LABORATORY ? II



? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the

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performance of refrigeration cycle / components

LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus

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2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder

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7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

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REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System

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15. Performance test in a fluidized Bed Cooling Tower



1. Able to find out the thermal conductivity of various materials.

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2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials

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6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.

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11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures

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14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
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CONTENTS


Sl.No.
Name of the experiment

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Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe

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apparatus
11
3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder

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15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS

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6
Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39

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9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58

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13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS

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16 Air conditioning test rig 75
PROJECT WORK 81

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Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

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Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:
(i) Experimental setup

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(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to

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prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater

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assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved

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aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK

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3. Area, A = ( ?/4) d
2
(10 + x)

cm

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2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.

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2. Increase the voltage gradually.

9 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there

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is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

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Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm

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4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40

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0
C ? 100
0
C
9. Maximum temperature of the hot plate = 170

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0
C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)

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13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)

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18. Temperature indicator = 0 ? 200
0
C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm

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21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:

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Sl. No. Voltmeter
V
Ammeter
A
Main heater (

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0
C) Test Plate (
0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water

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is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from

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thermocouple readings and is adjusted accordingly.

11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably

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steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

Result:

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Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded

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hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.

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6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer

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11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?

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16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

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Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup

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(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter
Theory:

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The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in

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the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:
1. Diameter of the heater Rod = 20 mm.

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2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).

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2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by

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Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging

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material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.
No.
Voltage

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(V)
Current
(A)
Heater Temperature
(

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0
C)
Asbestos Temperature
(
0

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C)
Saw dust
Temperature (
0
C)

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T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.

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4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.

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7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2

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-K

Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC

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engines, heat exchangers, etc. where heat transfer is to be found.

Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?

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4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?

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9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?

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14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis

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19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

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Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:
(i) Experimental setup

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(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at

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the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

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When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Schematic view of the test set-up:
mm
mm

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19 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm

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3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0

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C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V

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9. Heater = Cartridge type (400 W)

Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (

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0
c)

V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:

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1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2
K

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As = Area of heat transfer surface = ? x d x l m
2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0

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C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0
C) ?

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2. hL / k = A { g L
3
?T Cp ?/2v
2
}

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n

Where, hL / k are called Nusselt Number.
L
3

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g?T / v
2
is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.

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Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid

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? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0

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K
-1

Where Tf = (Ts + Ta )/ 2

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For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25
for 10

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4
< Gr.Pr.<10
8

hL / k = 0.13 (Gr.Pr)

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1/3
for 10
8
< Gr.Pr.<10
12

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Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

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Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2

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K
Experimental = ______________ W/ m
2
K

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Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?

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3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?

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8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer

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13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.

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18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No. 4

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

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Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:

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(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

Theory:

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Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat

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supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



Tabulations:

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Sl. No. Voltage Current Temperature in (
0
C)
Manometer

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reading of water
in h in meter

(V) (A)
T1

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T2

T3

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T4

T5

T6

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h1
cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm

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3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300

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0
C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A

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10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.

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4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:

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1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady

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state is reached.
4. Note down the heater input.

26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)

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?T = Temperature rise in air (
o
C)
= T6 ? T1.
2. m = Q?

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Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m

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3
/hr
3. ha = qa /A(Ts- Ta) W / m
2
K

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qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

Ta = Average temperature of air = (T1 + T6)/2

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o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C

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Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

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?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s

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2

using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number

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Where, V = velocity of air = Q/[(? x Di
2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2

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o
C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K

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Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

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k = Thermal conductivity of fluid W/m
2
K
Nu = 0.023 (Re)
0.8

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(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

Results:

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Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m
2
K

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htheoritical = -------------- W/m
2
K

Outcome:

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From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.

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6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?

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11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall

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Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The

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temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus

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uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.

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Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.

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Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.

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4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from

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the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate

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Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter
reading

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(V)
Ammeter
reading
(A)
T1

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(
0
C)
T2
(

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0
C)
T3
(
0

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C)
T4
(
0
C)

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T5
(
0
C)
T6

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(
0
C)
T7
(

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0
C)
T8
(
0

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C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:
The rate of heat transfer through different materials are found to be

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a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

Outcome:

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From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.



32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?

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3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.

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7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?

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12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

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Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between

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the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

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Procedure:

1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.

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3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter
reading( V)
Ammeter

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reading (A)
T1
(
0
C)

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T2
(
0
C)
T3

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(
0
C)
T4
(

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0
C)

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Calculations:

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The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Fig. 1 Apparatus of thermal conductivity of insulating powder

[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

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Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

Outcome:

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From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?

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6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?

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11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection

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16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.7

HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

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Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer
Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of

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the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:

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Forced convection:
Sl.
No.
V I

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Fin Temperatures (
0
C)
Ambient Temp
(

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0
C)
Manometer
Reading
(V)

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(A)

T1 T2 T3 T4 T5 T6 T7 T8
h1

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cm
h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm

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5. Diameter of the delivery pipe (O.D) = 46 mm

Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64

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8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0

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C
12. Temperature indicator = 0 ? 300
0
C
(With compensation of ambient temperature up-to 50

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0
C)
13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V

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T7 T6 T5 T4 T3 T2 T1
T8
Brass Pin Fin
Heater

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38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.

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7. Do not exceed 200 W.
Procedure:
Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.

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2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.

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Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D

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2
) /4}?2gha m
3
/s.
Where, ha (head of air) = (?w / ?a) x H m

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H = Difference of water level in manometer m
?w Density of water = 1000 kg/m
3

?a = Density of air = 1.165 kg/m

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3
g = acceleration due to gravity = 9.81 m/s
2

Cd = Coefficient of discharge = 0.64

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D = diameter of the orifice
3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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A = area of the duct
4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?

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D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2
o
C

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5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number
6. Nusselt Number:
Nu = CRe
m

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(Pr)
0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m

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k= 386 w/mk
m= ?(hp/kA)
A = area of fin = (? x D
2
) /4

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L = Length of the fin
Tw ? average temperature
T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:

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Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

Outcome:

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From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.

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40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.

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4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer
6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction

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9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?
11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?

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14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.8

DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

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Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer

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(ii) Electric Heater
(iii) Stop watch
(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The

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outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A

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chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:

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1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve

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6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C

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= (or) 0.1 Kcal / kg
0
C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

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42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

11. Temperature indicator digital 0.1
0

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C L.C 0 - 200
0
C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW

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13. Tank for hot water
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:

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Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4
? Td
4
)

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Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

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Schematic view of the test set-up:

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Heater

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Tabulations:

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Proc
edur
e:
1. H
eat the

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water
in the
tank by
the immersion heater up to a temperature of about 90
0

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C.
2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant

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cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

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Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m
2
k
4

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.

Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus

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is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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Sl. No.
Hemisphere Temperature(
0
C) Avg. Temp.

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of the
Hemisphere
(Th)
T4
Steady

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Temp. of
Disc
T0 (Td)
Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?
3. State Planck?s distribution law.

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4. Define ? Biot Number
5. State Wien?s displacement law.
6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.
8. What are the various types of convection?

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9. Define ? Condensation
10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?
13. State Krichoff's law or radiation

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14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.9

DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

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Aim:
To measure emissivity of the test plate surface at various temperature
Apparatus required:
(i) Experimental setup

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(ii) Thermocouples
(iii) U ? tube manometer
Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide

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undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.

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Specifications:
1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.

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Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.

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9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300
0
C.

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.

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5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.
Tabulation:
Sl.
No

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Voltage

Current

Black body

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temp(
0
C)
Avg.
temp.

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Polished body
temp (
0
C)

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Avg.
temp.

Enclosure
Temp.

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(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:

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Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts
4
? Ta
4

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) A
Eb ? E = (W1 ? W2) / ? (Ts
4
? Ta
4

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) A
E = Eb ? {(W1 ? W2) / ? (Ts
4
? Ta
4

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) A}
Where,
W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd

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2
m
2

T = Temperature of black plate, k = (Ts + Ta) / 2

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Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)
Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

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47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

? = Stefan boltzman constant = 5.67 x 10
-8
W/m

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2
K
4

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Schematic view of the test set-up:


Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.

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And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by
the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

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Results:
The emissivity of the test plate surface is found to be _____________.
Outcome:
From this experiment, finding the emissivity of the test plate surface at various

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temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Emissivity

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2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?
4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?
6. What is meant by shape factor?

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7. Define ? Radiation
8. What is meant by monochromatic emissive power?
9. Define ? Emissive Power
10. What is meant by absorptivity?
11. Define ? Black Body

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12. What is meant by transmissivity?
13. State Plank's distribution law
14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.10

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EFFECTIVENESS OF PARALLEL / COUNTER
FLOW HEAT EXCHANGE

Aim:

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To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:
(i) Experimental Setup
(ii) Stop watch
(iii) Thermometer

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Theory:
Heat exchangers are classified in three categories:
1. Transfer type
2. Storage type
3. Direct contact type.

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A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.
The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.

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iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water
which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run

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as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:
1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm

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4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50
0
C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100

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0
C - 2 Nos.
7. Measuring flask = 0 ? 1000 CC

50 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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8. Geyser: single phase type to obtain hot water supply
9. Thermo Cole insulation for outer pipe.
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically

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there is no temperature rise in the circuiting fluid.
Tabulations:
Sl.
No.
Flow Hot Fluid (

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0
C) Cold Fluid (
0
C)
Time for

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collection of
hot fluid
Kg/sec
Time for
collection

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of cold fluid
Kg/sec
1 Parallel flow
Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)
1. Area of the pipe A = ? (D ? d) L
Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube

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L = Length of the tube

2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

51 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Where, m = mass flow rate Kg/ sec.
m = ?v/t, ? = density of water and t = time taken for hot water
Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet

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Tho = Temperature of hot water outlet

3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W
Where, m = mass flow rate
Cp = Specific heat of capacity

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Tco = Temperature of cold water inlet
Tci = Temperature of cold water outlet
4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W
Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)

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?Tm = (?Ti - ?To) / In (?Ti/?To)
Where, ?To = Tho ? Tco
?Ti = Thi ? Tci
6. Over all heat transfer coefficient
h = Q?/?Tm A W/m

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2
K
where Q? = (Qa + Qc) / 2

Procedure:

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1. Place the thermometers in position and note down their readings when they are at room temperature and
no water is flowing at either side. This is required to correct the temperature.
2. Start the flow on hot water side.
3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.

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5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.
6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.
7. Keeping the flow rates same, wait till the steady state conditions are reached.
8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.

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10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Result:
1. The values of effectiveness of heat exchanger were found as
(i) Parallel flow = ________.
(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)

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(i) Parallel flow = ________.
(ii) Counter flow = _________.

Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow

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heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat
exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Heat Exchanger
2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?

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4. Write about the merits of drop wise condensation.
5. What is meant by film wise and drop wise condensation?
6. What is meant by effectiveness?
7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?

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9. Distinguish between regenerator and recuperates.
10. What is meant by parallel flow heat exchanger?
11. What is meant by counter flow heat exchanger?
12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?

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Viva ? voce

53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.11

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DETERMINATION OF COP OF A REFRIGERATION
SYSTEM

Aim:

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To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration
system
Apparatus required:
(i) Thermometer
(ii) Electric Heater

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(iii) Stop watch
(iv) Experimental setup
Description:
1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a
reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.

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2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated
wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a
low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the
temperature of chilled water. The above unit is located on the trolley behind front panel.
3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic

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expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum
strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure
gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high
pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy
meter to measure the power consumed either by hater or by compressor.

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54 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
A. A compressor condenser unit placed inside trolley and fitted with

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1. R-134a reciprocating compressor
2. Condenser
3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan
4. A receiver with angle check valve
B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity

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placed inside a well insulated wooden box and provided with
5. Evaporator coil
6. Stirrer
7. Electric heater 230 V, A.C.
8. The sensing bulb of low temperature thermostat.

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9. A high temperature thermostat.
10. A Thermometer to measure the chilled water temperature
C. The front panel on which are mounted the following
11. Capillary expansion tube with isolating valve.
12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator

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and isolating valve
13. Drier cum strainer and sight glass
14. Thermostat at inlet and outlet of both evaporator and condenser
15. Pressure gauge at inlet and outlet of evaporator and condenser
16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out

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17. Heat power regulator switch and regulator
18. Energy meter to measure the power consumed either by hater or by compressor.

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55 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.
2. The heater regulator should be switched off whenever not in use. Heating water beyond 40

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0
C may lead to
permanent damage of the entire system. A high temperature cut off thermostat is provided in the water
chiller, to cut off the heater beyond 30
0

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C.Check the setting of the same before operation.
3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.
4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.
5. The solenoid thermostat is adjusted to cut at 15
0

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C and cut in at 10
0
C of the chilled water. Do not alter the
same.
6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.

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7. The space near the condenser should permit good ventilation to aid proper fan performance.
8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked
in
0
F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,

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calibrated in SI units, are not available.)
9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to
obtain the pressure in MN/m
2
.e.g. P = x psig

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= (x + 14.7) psia
= (x + 14.7) / 145 MN/m
2
(MPa)
10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.

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Formulae used:
Let, State 1 indicates the entry of compressor.
State 2 indicates the exit of compressor.
State 3 indicates the exit from condenser.
State 4 indicates the entry to evaporator

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P = Pressure (bar)
T = Temperature (
0
C)
H = Specific enthalpy (kJ/kg)

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v = Specific Volume (m
3
/Kg)
n = Number of revolutions of energy meter disc.
t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)

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t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)
K = Energy meter constant = 3200 lmp / kWh
N = Speed of compressor = 2840 rpm
h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

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56 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2
h3 = Specific enthalpy at Pc and T3 (kJ/kg)
h4 = h3

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Stroke volume of compressor = (?/ 4) d
2
l = 12.58 x 10
-6
m

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3

1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar
2. Average condenser pressure, Pc = (P2 + P3) / 2 bar
3. Heater input, Qe = (n / t1) x (3600 / k) kW

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4. Compressor input, W = (n / t2) x (3600 / k) kW
5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1
6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)
7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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57 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

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Sl.
No.

Initial

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Temp.
of water

Final
Temp.

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of water
Duration
of exp.

Delivery

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pressure

Delivery
Temp.

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Condense
Outlet
Pressure

Condense

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Outlet
Temp.


Pressure

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after
throttling

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Temp.
After
Throttli

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ng


Suction
pressur

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e
Suction
Temp.

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Time for
10 rev. of
compress

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or energy
meter

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Height
of water
in the
vessel

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58 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
Load Test with Capillary tube as expansion device:
1. Fill the chilled water calorimeter with pure water so that the evaporative coils are
fully immersed.

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2. Select the capillary tube line by opening the shut-off valve on this line and closing
the one on the thermostatic expansion valve line. The solenoid switch is switched OFF.
3. Start the compressor and run for some time so that the chilled water temperature
is lowered to the given test temperature.
4. Switch on the heater and slowly increase the power.

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5. Allow The temperature in water calorimeter to reach the equilibrium
temperature.
6. Connect energy meter to motor and heater by the selector switch one after another
and note down the time taken for 10 pulses of the energy meter disc.
7. Note down the pressure and temperature readings at locations 1,2,3 & 4 as

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mentioned.
8. Switch OFF the heater and the mains.
Result:
The load test on a refrigeration test rig was conducted and the results are as follows.
1. Actual C.O.P. of the system =____________.

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2. Rhetorical C.O.P. of the system = ___________.
3. Volumetric Efficiency = ___________.

Outcome:
From this experiment, conducting the load test on a refrigeration test rig and finding out the

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volumetric efficiency and co-efficient of performance for any type of refrigerant is learnt and this experiment
could be used in the areas such as Refrigerator and Air Conditioning.
Applications:
Refrigerator, Air Conditioning.

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59 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? COP
2. Which thermodynamic cycle is used in air conditioning of airplanes using air as refrigerant?
3. Define ? Ton of Refrigeration

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4. What is meant by refrigeration?
5. What is meant by air conditioning?
6. What are the four important properties of a good refrigerant?
7. How does the actual vapour compression cycle differ from that of the ideal cycle?
8. Name any four commonly used refrigerants.

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9. What are the expansion devices used in a vapour compression plant?
10. Why throttle valve is used in place of expansion cylinder for vapour compression refrigerant machine?
11. What are the merits of air refrigeration system?
12. What are the demerits of air refrigeration system?
13. Define ? Refrigerant

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14. What is net refrigerating effect of the refrigerant?
15. What are the methods to obtain sub cooling of refrigerant?

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Viva ? voce

60 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.12 EXPERIMENTS ON PSYCHROMETRIC PROCESS

Aim:

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To conduct an experiment on psychrometric processes with air conditioning system
Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch

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(iv) Digital anemometer
(v) Experimental setup
Description:
The test rig consist of
1. An air duct support of stand

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2. A blower to set up air flow through the duct along with a speed control to vary the
velocity of air.
3. A heater to rise the air temperature with regulator and energy meter.
4. Water spray, collecting tray, reservoir with gauge pump.
5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.

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(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after cooling coil).
6. The test rig consist of compressor, condenser unit placed inside trolley and fitted
with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for
condenser and (iv) Liquid receiver.
7. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and

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corrosion damage.

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61 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Observation Table: I

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Precautions:
1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence
avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kw only for the motor
circuit.
2. Natural air currents in the room if in the direction of air duct may defect the experimental results and

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hence the duct should be placed such that no wind from doors, windows, fan and cooling air from
other test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan
and should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase
beyond 240 psi.
3. Never exceed dry bulb temperatures of 40

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0
C after the heater (station 2) otherwise the air duct may be
damaged.
4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may
exceed its maximum of 32

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0
C and calibration may be affected.
5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not
running this will lead to rise in temperature at the heater and may damage the heater and the air duct.
6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their

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duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.
7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer
is placed inside the reservoir at the top. This may have to the cleaned when necessary.
8. Do not open the gate valve fully otherwise water may be splashed outside and the waster
measurement may be in error.

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S.
N
o
Inlet temp
Outlet

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temp
Pressu
re
P1
Tem

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p.
T1
Pressu
re
P2

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Temp.
T2
Pressu
re
P3

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Tem
p.
T3

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Pressu
re
P4

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Temp.
T4
Energy
for 10

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revolutio
ns
Twet Tdry Twet Tdry Lb/in
o
C Lb/in

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o
C Lb/in
o
C Lb/in
o

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C


62 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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9. If the low pressure cut out comes in to action, it means that the Freon charge is insufficient and may
have to be filled up. The suction pressure should never go below 2 psi as otherwise the compressor
seals will be damaged and air and moisture may enter the system.
10. The refrigerant strainer placed on the front panel should always be warm. If it cools and moisture
condenser on it, then the strainer might have to be charged by an experienced refrigeration

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mechanics.
11. The refrigerating system can work continuously for 2 hours, however if the room temperature is above
25
0
C the condenser may be heated up and the delivery pressure may rise. Do not exceed 240 psi.

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Pour one or two glasses of drinking water over the fins of the condenser in order to reduce the
delivery pressure.
12. After some months of operation the compressor may have to be topped up with oil and some quantity
of Freon-22 may have to be charged by an experienced mechanics.
13. See that distilled water is filled up in the plastic dishes provided under the wet bulb thermometers and

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that the wicks are in tact otherwise erroneous readings may be obtained. These thermometers will
show correct readings only when the fan is in operation.
14. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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Formulae used:
1. Corresponding to the dry and wet bulb temperature at all the stations obtain the specific enthalpy and
specific humidity values from psychrometric chart.
i.e., h1 and w1 at tb1 and tw1 and so on.
2. Air flow rate, ma = (A x V) / v4 Kg / sec

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Where, A = Area of duct at outlet in m
2
(0.46 m x 0.086 m)
V = Air velocity ( m / sec)
V4 = Specific volume of moist air at station 4 using psychometric chart m

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3
/Kg
3. Moisture added from psychrometric chart, mw1 = ma (w3-w2) Kg / sec.
Where, w3 = Specific humidity at station 3
w2 = Specific humidity at station 2

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4. Cooling effect produced on air, Qe = ma (h3 ? h4) kW.
Where, h3 = Specific enthalpy at state 3 kJ/kg
h4 = Specific enthalpy at state 4 kJ/kg
5. Moisture condensed, mcl = ma (w3 ? w4) kg/sec
Where, w3 = Specific humidity at station 3

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w4 = Specific humidity at station 4

63 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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1. Fill water in the wet bulb temperature probe trays.
2. Start the main.
3. Start the blower and run it the required speed by keeping the speed regulator at
position.
4. Start the spray pump and open the gate valve suitably.

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5. Start the heater.
6. Select the expansion device (Capillary tube / Thermostatic expansion valve)
7. Start the cooling compressor.
8. Wait for some time till thermometers shown practically constant readings and note down the
following readings:

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(i) Dry bulb temperatures tdb1, tdb2, tdb3, tdb4.
(ii) Wet bulb temperatures twb1, twb2, twb3, twb4.
(iii) Spray water temperature, ts
(iv) Surface temperature of cooler, tm ( at control panel)
(v) Pressure gauge reading, pd ( at control panel)

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(vi) Compound gauge reading, Ps ( at control panel)
(vii) Level reduction?l? in spray reservoir (mm) during 5 min.
(viii) Amount of condensate collected ?lc?, in a measuring jar at cooler tray during a
run of 5 minutes at constant conditions.
(ix) Time in second ?SH? for 10 pulses of the energy meter disc connected to the

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heater.
(x) Time in seconds Sc for 10 pulses of the energy meter disc connected to cooler
compressor.
Result:
Experiment on psychrometric processes with air conditioning system was drawn

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Outcome:
From this experiment, conducting the test on psychrometric processes with air
conditioning system is learnt and this experiment could be used in all types of air conditioning systems.

Applications:

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Air Conditioning.



64 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the commonly used unit of refrigeration?
2. Distinguish between summer air conditioning and winter air conditioning.

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3. Define ? RSHF Line
4. Define ? By Pass Factor of a Heating Coil
5. What is the effect of sub cooling a refrigerant in a vapour compression cycle?
6. What is the function of analyzer and rectifier in an absorption system?
7. What is the purpose of generator assembly in vapour absorption refrigeration system?

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8. State the substance used in the Lithium Bromide system and their functions.
9. Differentiate wet compression from dry compression.
10. Define ? Apparatus Dew Point
11. What is meant by dew point temperature?
12. Define ? Wet Bulb Temperature

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13. Define ? Degree of Saturation
14. What is meant by specific humidity?
15. Define ? Relative Humidity

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Viva ? voce

65 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.13

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PERFORMANCE TEST ON A RECIPROCATING
AIR COMPRESSOR

Aim:

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To conduct a load test on the 2 - stage reciprocating air compressor to determine the isothermal and
volumetric Efficiencies at various delivery pressures

Apparatus required:
* Air compressor with accessories.

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* Stop watch.
Description:
Two stage air compressors is a reciprocating type driven by a prime mover. The test rig consist of a base on
which the tank is mounted. The outlet of the compressor is connected to the receiver. The suction is
connected to air tank with a calibrated orifice plate through a water manometer. The input to the motor is

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recorded by an energy meter. The temperature and pressure of the air compressed is indicated by a
thermometer and pressure gauge.
Specifications:
1. Air compressor:
* LP Bore, DLP = 63.0 mm.

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* HP Bore, DHP = 79.0 mm.
* Stroke, L = 80.0 mm.
* Speed, N = 1440 rpm (5 HP)
* Effective radius = 0.193 m
2. Air receiver capacity = 0.33 m3

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3. Orifice, diameter, d0 = 12 mm
4. Orifice area,. A0 : ?d0
2
/ 4 = ----------- m
2

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5. Coefficient of discharge C d. = 0.6
6. Energy-meter constant = 200 rev / kWh

66 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I

Observation Table: II
Sl.

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No.
Actual
Discharge
Va
Theoritical

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Discharge
Vt
Volumetric
Efficiency
?

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Power
Input

Output
Power

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Overall
Efficiency
?0
Isothermal

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Workdone
IwD
Polytropic
Workdone
PwD

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Isothermal
Efficiency
?iso
m
3

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/sec m
3
/sec % kW kW % J/Kg J/Kg %

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Sl.
No.
Pressure
p
Manometer

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h1
Manometer
h2
Time for 5 revolutions Energy meter Speed of the compressor Temperature
T1

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Temperature
T1
Kg/cm
2
Cm cm sec rpm

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o
C
o
C

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67 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:

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1. Check whether manometer is filled with water up to the required level.
2. The maximum pressure in the receiver tank should not exceed 12 kg / cm
2

Procedure:

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1. Ensure that gauge pressure in the tank is zero.
2. Start the compressor. Read the receiver pressure gauge for a particular pressure.
3. Maintain the pressure constant by adjusting the outlet valve.
4. Note down the manometer reading and time taken for 3 revolution of the energy
Formulae used:

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1. Density of air at RTP:
? RTP = ? NTP X 273 Kg/ m
3

(273 + Room Temp)

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Where density of air at NTP = 1.293 Kg/ m
3
.

2. Air head causing flow:

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ha RTP = (h1 - h2) x ? water m
?a RTP
Where,
(h1- h2) = Difference in manometer liquid, in m.

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3. Actual volume at RTP:
Va RTP = C.d x Ao x ? 2 g ha RTP
Where,
C d= Coefficient of discharge = 0.6.
A o = Area of orifice = ?(d0)

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2
m
2
.
4

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Diameter of orifice d o = 0.01 m.
4. Actual volume at NTP:
Va NTP = VaRTP x T NTP
T RTP
Where,

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T NTP = Normal temp - 273
o
k
T RTP = Room temp -
o

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c (273 + TROOM )

68 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

5. Theoretical Volume of air: (at intake conditions)

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V T = ?D
2
x L x Nc m
3
/ sec.

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4 x 60
D = LP Bore diameter = 88.5 mm.
L = Stroke length = 88.9 mm.
Nc = Compressor speed rpm.
6. Volumetric Efficiency:(for LP stage)

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?vol = Va NTP x 100%
Vt
7. Shaft Input through Energy meter:

= 1 x n x ?t x ?m x 3600 kw.

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( Ec x t )
Where,
Ec = Energy meter constant = 200 rev / kWh
?t = Efficiency for transmission = 0.95.
? m = Efficiency for motor = 0.90.

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t = Time for 'n' revolution of energy meter disc.
n = no. of rev. of Energy meter disc.

8. Isothermal power:
= Pa x Va RTP x log e (R) W

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1000
Pa = Atmospheric pressure in N/ m
2
= 1.01325 x 10
5

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N / m
2
.
R = (Pressure gauge reading + atmospheric pressure)
atmospheric pressure.

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9. Isothermal efficiency:
? ISO = Isothermal power x 100%
Shaft input

Result:

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The values of isothermal and volumetric efficiency at various delivery pressures have been studied &
graph between Pressure Vs Volumetric efficiency and Pressure Vs Isothermal efficiency are drawn.


69 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Outcome:
From this experiment, conducting the load test on two stage reciprocating air compressor for
determining the isothermal and volumetric Efficiencies at various delivery pressures is understood and this
experiment could be used in the areas such as Refrigerator, Air Conditioning, IC engines, etc.

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Applications:
Refrigerator, Air Conditioning, IC engines.

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1. How are air compressors classified?
2. Define ? Isothermal Efficiency of Air Compressor
3. What is meant by FAD (Free Air Delivery)?
4. What is meant by perfect inter-cooling?
5. Define ? Clearance Ratio of an Air Compressor

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6. List out the applications of compressed air.
7. What are the types of air compressors?
8. What is meant by single acting compressor?
9. What is meant by double acting compressor?
10. What is meant by single stage compressor?

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11. What is meant by multi stage compressor?
12. Indicate the applications of reciprocating compressors in industry>
13. Define ? Mechanical Efficiency
14. What is meant by compression ratio?
15. What are the factors that affect the volumetric efficiency of a reciprocating compressor?

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Viva ? voce

70 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.14

PERFORMANCE TEST IN A HC REFRIGERATION
SYSTEM

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Aim:

To conduct the performance test on Vapour Compression Refrigeration System and to determine the
Coefficient of Performance using solenoid valve by throttling method

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Description:

In this system the working fluid is a HC out of a refrigeration system. The HC compression system is most
important system from the view point of commercial and domestic utility. The HC refrigerant at low temp and

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pressure enters the reciprocating compressor, where it is compressed isentropically and subsequently its temp
and pressure increases considerably. This HC after leaving the compressor enters the condenser where it is
cooled into low temperature. Then it is sucked by reciprocating compressor and is thus repeated.
Formula used:

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Actual COP = refrigerant effect
I/p energy to compressor
Refrigerant effect = mxCpx ? T
t
m - mass of water (kg)

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Cp - Sp. Heat of water (4.2 kJ/kg K)
?T ? decrease in temp (Ti-Ts)
t - timetaken duration of expt (sec)

Energy input =n x 3600 /k x t

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n ? number of revolutions in energy meter
t ? time taken of ?n? revolutions
k ? energy meter constant (3200)

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71 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:

Pressure of the refrigerant (Mpa) Temperature Time for n?

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rev of
energy
meter in
sec
P1 P2 P3 P4 Circulating fluid

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temp
Refrigerant temp

Ti Tf T1 T2 T3 T4

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72 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Model calculation:

Actual COP = refrigerant effect

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I/p energy to compressor

Refrigerant effect = mxCpx ? T
t
m - mass of water (kg)

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Cp - Sp. Heat of water (4.2 kJ/kg K)
?T ? decrease in temp (Ti-Ts)
t - time taken duration of experiment (sec)
Refrigerating effect = 8x4.2x (27-6)/1200=0.588 kw

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Energy input = n x 3600
n ? Number of revolutions in energy meter
t ? Time taken of ?n? revolutions
k ? Energy meter constant
=3 x 3600/(1200 x 54)

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=0.166 kW
Actual COP = refrigerant effect
I/p energy to compressor
= 0.588/0.166
=3.526

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Result:

The experiment was conducted successfully and coefficient of performance was found out is _______.

Outcome:

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From this experiment, conducting the performance test on Vapour Compression Refrigeration
System and to determine the Coefficient of Performance using solenoid valve by throttling method is
understood and this experiment could be used in the areas such as Refrigerator and Air Conditioning systems.
Applications:
Refrigerator, Air Conditioning.

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73 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the difference between air conditioning and refrigeration?
2. Write any three important properties of a good refrigerant.
3. What is the function of analyzer and rectifier in an absorption system?
4. How does humidity affect human comfort?
5. What is the commonly used unit of refrigeration?

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6. Distinguish between summer air conditioning and winter air conditioning.
7. Define ? RSHF Line
8. Define ? By Pass Factor of a Heating Coil
9. What is the effect of sub cooling a refrigerant in a vapour compression cycle?
10. What is the function of analyzer and rectifier in an absorption system?

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11. What is the purpose of generator assembly in vapour absorption refrigeration system?
12. State the substance used in the Lithium Bromide system and their functions.
13. Differentiate wet compression from dry compression.
14. Define ? Apparatus Dew Point
15. What is meant by dew point temperature?

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16. Define ? Wet Bulb Temperature
17. Define ? Degree of Saturation
18. What is meant by specific humidity?
19. Define ? Relative Humidity
20. What is meant by dew point temperature?

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Viva ? voce

74 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.15

PERFORMANCE TEST IN A FLUIDIZED BED
COOLING SYSTEM

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Aim:
To determine the performance test on cooling tower
Introduction:
The cooling tower is one of the most important device in chemical industries for example when the hot

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water come from heat exchanger we use the cooling tower to cool it The purpose of cooling tower is to cool
relatively warm water by contacting with unsaturated air. The evaporation of water mainly provides cooling. In
typical water cooling water tower warm water flows countercurrent to an airstream. Typically, the warm water
enters the top of the packed tower and cascades down through the packing , leaving at the bottom Air enters
at the bottom of the tower and flows upward through the descending water . The tower packing often consist of

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slats of plastic or of packed bed. The water is distributed by troughs and overflows to cascade over slat
gratings or packing that provides large interfacial areas of contact between the water and air in the form of
droplets and films of water. The flow of air upward through the tower can be induced by the buoyancy of the
warm air in the tower (natural draft) or by the action of a fan . The water cannot be cooled below the wet bulb
temperature. The driving force for the evaporation of water is approximately the vapour pressure of the water

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less the vapour pressure it would have at the wet bulb temperature
Procedure:
1. Introduce water and record its flow rate.
2. Switch ON the heaters on so that water is heated to the required temperature.
3. Introduce air and record its flow rate.

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4. Wait for steady state then record steady state dry and wet bulb temperature of air at the entrance and
exit.
5. Record the inlet and outlet temperature and flow rate of water also record temperature at different
stages.
Tabulation:

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Sl.No. T1 (
0
c) T2 (
0

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c) T3 (
0
c) Efficiency

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T1 = room temperature

75 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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T2 = water inlet
T3 = water outlet

Efficiency of cooling tower

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ECT = T3/T2/*100

Model calculation:

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Efficiency of cooling tower = water outlet
--------------- *100
Water inlet

= 36/40 *100

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= 90
Result:
The performance test in cooling tower is determined as ______%.
Outcome:

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From this experiment, conducting the performance test on cooling tower is understood and this
experiment could be used in various power plants where cooling tower is used.
Applications:
Power Plant Cooling Tower, Cooling Tower.

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1. What are functions of a draught system?
2. What are the advantages of burning coal in pulverized form?
3. What are the functions of cooling tower?
4. What are the different types of draught system?

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5. What are the methods used for handling of coal?
6. What is meant by fluidized bed combustion?
7. What is the use of fluidized bed boiler?
8. What are the types of fluidized bed boiler?
9. State the purpose of condenser in fluidized bed boiler.

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10. What is meant by pulveriser and why it is used?
11. State the disadvantages of pulverized coal firing.
12. Distinguish between fouling and slagging.
Viva ? voce

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76 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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ADDITIONAL EXPERIMENTS
BEYOND THE SYLLABUS

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77 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.16 AIR CONDITIONING TEST RIG

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Aim:
To conduct a performance test on air conditioning test rig and determine the Coefficient of Performance of
air conditioning system
Apparatus required:

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(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Digital anemometer
(v) Experimental setup

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Description:
The test rig consist of
1. An air duct support of stand
2. A blower to set up air flow through the duct along with a speed control to vary the
velocity of air.

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3. A heater to rise the air temperature with regulator and energy meter.
4. Water spray, collecting tray, reservoir with gauge pump.
5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.
(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after
cooling coil).

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6. The test rig consists of compressor, condenser unit placed inside trolley and fitted
with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan
for condenser and (iv) Liquid receiver.

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78 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I

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Air conditioning Test Rig

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Sl.
No

Inlet

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temperat
ure

Outlet
temperatu

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re

Pressu
re
P1

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Tem
p.
T1

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Pressu
re
P2
Temp.
T2

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Pressu
re
P3

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Tem
p.
T3

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Pressu
re
P4

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Tem
p.
T4

Energy for

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10
revolutions
Twet Tdry Twet Tdry Lb/in
o
C Lb/in

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o
C Lb/in
o
C
Lb/in

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o
C

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79 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence
avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kW only for the motor circuit.

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2. Natural air currents in the room if in the direction of air duct may defect the experimental results and
hence the duct should be placed such that no wind from doors, windows, fan and cooling air from other
test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan and
should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase beyond
240 psi.

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3. Never exceed dry bulb temperatures of 40
0
C after the heater (station 2) otherwise the air duct may be
damaged.
4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may

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exceed its maximum of 32
0
C and calibration may be affected.
5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not
running this will lead to rise in temperature at the heater and may damage the heater and the air duct.

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6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their
duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.
7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer is
placed inside the reservoir at the top. This may have to the cleaned when necessary.
8. Do not open the gate valve fully otherwise water may be splashed outside and the waster measurement

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may be in error.
9. If the low pressure cut out comes in to action, it means that the Freon charge is insufficient and may have
to be filled up. The suction pressure should never go below 2 psi as otherwise the compressor seals will
be damaged and air and moisture may enter the system.
10. The refrigerant strainer placed on the front panel should always be warm. If it cools and moisture

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condenser on it, then the strainer might have to be charged by an experienced refrigeration mechanics.
11. The refrigerating system can work continuously for 2 hours, however if the room temperature is above
25
0
C the condenser may be heated up and the delivery pressure may rise. Do not exceed 240 psi. Pour

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one or two glasses of drinking water over the fins of the condenser in order to reduce the delivery
pressure.
12. After some months of operation the compressor may have to be topped up with oil and some quantity of
Freon-22 may have to be charged by an experienced mechanics.

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80 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. Corresponding to the dry and wet bulb temperature at all the stations obtain the specific enthalpy and
specific humidity values from psychometric chart.
i.e., h1 and w1 at tb1 and tw1 and so on.
2. Air flow rate, ma = (A x V) / v4 kg / sec

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Where, A = Area of duct at outlet in m
2
(0.46 m x 0.086 m)
V = Air velocity ( m / sec)
V4 = Specific volume of moist air at station 4 using psychometric chart m

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3
/kg
3. Heat added, Q1 = ma (h2 ? h1) kW
Where, h1 = Specific enthalpy at station 1 kJ/kg
h2 = Specific enthalpy at station 2 kJ/kg

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4. Moisture added from psychrometric chart, mw1 = ma (w3-w2) Kg / sec.
Where, w3 = Specific humidity at station 3
w2 = Specific humidity at station 2
5. Compressor power, W = (n / t) x (3600 / k) kW.

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Where, n = No. of pulses of energy meter disc
t = Time taken for ?n? no. of pulses (sec)
k = Energy meter constant (3200 lmp / kW-hr)
6. Actual C.O.P = Cooling effect produced on air / Compressor power.
7. Cooling effect produced on air, Qe = ma (h3 ? h4) kW.

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Where, h3 = Specific enthalpy at state 3 kJ/kg
h4 = Specific enthalpy at state 4 kJ/kg
8. Moisture condensed, mcl = ma (w3 ? w4) Kg/sec
Where, w3 = Specific humidity at station 3
w4 = Specific humidity at station 4

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9. Draw the psychrometric process.

Procedure:
1. Fill water in the wet bulb temperature probe trays.
2. Start the main.

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3. Start the blower and run it the required speed by keeping the speed regulator at position.
4. Start the spray pump and open the gate valve suitably.
5. Start the heater.
FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart

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and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION

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VISION
MISSION
4 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence

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To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design

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products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies

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5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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5 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering

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2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools

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6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms

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9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder

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4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant

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9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system

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12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection

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experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.

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12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC

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Boiler.



COURSE OBJECTIVES

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COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS

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1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11

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3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21

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5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31

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7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47

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CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14

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Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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8 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate

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method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters

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together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples

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No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2

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(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help

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of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:

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1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm

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6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100

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0
C
9. Maximum temperature of the hot plate = 170
0
C

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10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V

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15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0

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C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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10 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:
Sl. No. Voltmeter
V

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Ammeter
A
Main heater (
0
C) Test Plate (

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0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:

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1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single

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phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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11 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.

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8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.

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3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?

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8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?

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13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?

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18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:

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To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple

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(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.

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There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.

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4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.

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4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging

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k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:

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Sl.
No.
Voltage
(V)
Current

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(A)
Heater Temperature
(
0
C)

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Asbestos Temperature
(
0
C)
Saw dust

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Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos

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layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:

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The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)

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6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?

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11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.

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16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical

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tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which

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in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.

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The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Schematic view of the test set-up:

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mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch

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Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples

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6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}

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Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W

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Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L
3

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?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v
2

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is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid

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v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity

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?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.

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hL / k = 0.56 (Gr.Pr)
0.25
for 10
4
< Gr.Pr.<10

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8

hL / k = 0.13 (Gr.Pr)
1/3
for 10

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8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).

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3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:

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The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m

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2
K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing

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heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?

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5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)

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10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness

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15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?

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20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:

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To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer

Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air

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stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of

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orifice meter and the water manometer fitted on the board.


24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

Sl. No. Voltage Current Temperature in (

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0
C)
Manometer
reading of water
in h in meter

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(V) (A)
T1

T2

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T3

T4

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T5

T6

h1

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cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor

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5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0
C

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(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:

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1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.

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6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.

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2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. The rate at which air is getting heated is calculated as

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qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o

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C)
= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate

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Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m
3
/hr

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3. ha = qa /A(Ts- Ta) W / m
2
K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m

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2

Ta = Average temperature of air = (T1 + T6)/2
o
C

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Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C
Cd = 0.64
H = Difference of water level in manometer m

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?w Density of water = 1000 Kg/m
3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

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d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

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using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2

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)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o
C

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5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

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27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k

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? = Viscosity Ns/m
2

k = Thermal conductivity of fluid W/m
2

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K
Nu = 0.023 (Re)
0.8
(Pr)
0.4

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Bulk mean temperature = (T1 + T6)/2

Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.

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hactual = -------------- W/m
2
K
htheoritical = -------------- W/m
2

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K

Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?

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3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?

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8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection

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13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

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Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,

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the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure

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temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat

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flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm

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2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.

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2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

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30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature

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gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:

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Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R

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Tabulation:
Sl.No. Voltmeter
reading
(V)
Ammeter

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reading
(A)
T1
(
0

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C)
T2
(
0
C)

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T3
(
0
C)
T4

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(
0
C)
T5
(

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0
C)
T6
(
0

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C)
T7
(
0
C)

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T8
(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Composite wall apparatus set-up

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Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W

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c. Asbestos section = ------------W

Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure

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Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?

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5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.

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9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

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33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

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DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

Aim:
To find out the thermal conductivity of insulating powder by conduction

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Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A

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multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

Procedure:

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1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.

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5. Repeat the experiments for different power inputs.


The readings are tabulated below

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Sl.No. Voltmeter
reading( V)
Ammeter
reading (A)
T1

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(
0
C)
T2
(

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0
C)
T3
(
0

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C)
T4
(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm

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The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Fig. 1 Apparatus of thermal conductivity of insulating powder

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[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

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Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam

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boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity

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3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.

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8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?

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13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?

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18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

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HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

Aim:

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To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is

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measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:
Sl.

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No.
V I

Fin Temperatures (
0

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C)
Ambient Temp
(
0
C)

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Manometer
Reading
(V)

(A)

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T1 T2 T3 T4 T5 T6 T7 T8
h1
cm
h2

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cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Duct size = 150 mm x 100 mm.

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2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

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Schematic view of the test set-up:



zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5

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10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C
12. Temperature indicator = 0 ? 300

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0
C
(With compensation of ambient temperature up-to 50
0
C)

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13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8

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Brass Pin Fin
Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.

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4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:

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Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.

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4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2

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Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m

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3
/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m

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3

?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s

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2

Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s

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Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

A = area of the duct

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4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.

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(T1 + T6) / 2
o
C
5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number

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6. Nusselt Number:
Nu = CRe
m
(Pr)
0.33

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7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk
m= ?(hp/kA)

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A = area of fin = (? x D
2
) /4
L = Length of the fin
Tw ? average temperature

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T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________

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Heat transfer, Q = ___________ W

Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.


40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer

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6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?

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11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.8

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DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

Aim:

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To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch

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(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water

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between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.

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When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere

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3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg

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8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C
= (or) 0.1 Kcal / kg
0

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C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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11. Temperature indicator digital 0.1
0
C L.C 0 - 200
0

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C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water
Precautions:

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Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4

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? Td
4
)
Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)

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Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

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43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulations:
Proc
edur

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e:
1. H
eat the
water
in the

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tank by
the immersion heater up to a temperature of about 90
0
C.
2. Remove the disc, D before pouring the hot water in the jacket.

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3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.

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6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m

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2
k
4
.

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Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using

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boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

Sl. No.

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Hemisphere Temperature(
0
C) Avg. Temp.
of the
Hemisphere

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(Th)
T4
Steady
Temp. of
Disc

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T0 (Td)
Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number
5. State Wien?s displacement law.

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6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation
10. What are the various modes of condensation?

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11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.9

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DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

Aim:

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To measure emissivity of the test plate surface at various temperature
Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The

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temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.
Specifications:
1. Heater input to black plate W1 = V1 x I1 W

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2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V

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6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300

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0
C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.

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Tabulation:
Sl.
No
Voltage

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Current

Black body
temp(
0

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C)
Avg.
temp.

Polished body

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temp (
0
C)
Avg.
temp.

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Enclosure
Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts

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4
? Ta
4
) A
Eb ? E = (W1 ? W2) / ? (Ts

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4
? Ta
4
) A
E = Eb ? {(W1 ? W2) / ? (Ts

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4
? Ta
4
) A}
Where,

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W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd
2
m

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2

T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)

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Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

47 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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? = Stefan boltzman constant = 5.67 x 10
-8
W/m
2
K

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4


Schematic view of the test set-up:

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Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by

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the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

Results:

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The emissivity of the test plate surface is found to be _____________.
Outcome:
From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

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48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Emissivity
2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?

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4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?
6. What is meant by shape factor?
7. Define ? Radiation
8. What is meant by monochromatic emissive power?

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9. Define ? Emissive Power
10. What is meant by absorptivity?
11. Define ? Black Body
12. What is meant by transmissivity?
13. State Plank's distribution law

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14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

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49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.10

EFFECTIVENESS OF PARALLEL / COUNTER

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FLOW HEAT EXCHANGE

Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:

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(i) Experimental Setup
(ii) Stop watch
(iii) Thermometer
Theory:
Heat exchangers are classified in three categories:

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1. Transfer type
2. Storage type
3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.

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The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water

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which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:

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1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50

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0
C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100
0
C - 2 Nos.

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7. Measuring flask = 0 ? 1000 CC

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8. Geyser: single phase type to obtain hot water supply

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9. Thermo Cole insulation for outer pipe.
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Tabulations:

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Sl.
No.
Flow Hot Fluid (
0
C) Cold Fluid (

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0
C)
Time for
collection of
hot fluid

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Kg/sec
Time for
collection
of cold fluid
Kg/sec

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1 Parallel flow
Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)

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1. Area of the pipe A = ? (D ? d) L
Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube
L = Length of the tube

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2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

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Where, m = mass flow rate Kg/ sec.

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m = ?v/t, ? = density of water and t = time taken for hot water
Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet
Tho = Temperature of hot water outlet

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3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W
Where, m = mass flow rate
Cp = Specific heat of capacity
Tco = Temperature of cold water inlet
Tci = Temperature of cold water outlet

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4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W
Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)
?Tm = (?Ti - ?To) / In (?Ti/?To)
Where, ?To = Tho ? Tco

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?Ti = Thi ? Tci
6. Over all heat transfer coefficient
h = Q?/?Tm A W/m
2
K

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where Q? = (Qa + Qc) / 2

Procedure:
1. Place the thermometers in position and note down their readings when they are at room temperature and
no water is flowing at either side. This is required to correct the temperature.

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2. Start the flow on hot water side.
3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.
5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.
6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.

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7. Keeping the flow rates same, wait till the steady state conditions are reached.
8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.
10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

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52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Result:
1. The values of effectiveness of heat exchanger were found as

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(i) Parallel flow = ________.
(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)
(i) Parallel flow = ________.
(ii) Counter flow = _________.

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Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow
heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat
exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Heat Exchanger
2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?
4. Write about the merits of drop wise condensation.
5. What is meant by film wise and drop wise condensation?

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6. What is meant by effectiveness?
7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?
9. Distinguish between regenerator and recuperates.
10. What is meant by parallel flow heat exchanger?

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11. What is meant by counter flow heat exchanger?
12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?
Viva ? voce

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53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.11

DETERMINATION OF COP OF A REFRIGERATION

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SYSTEM

Aim:
To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration
system

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Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Experimental setup

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Description:
1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a
reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.
2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated
wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a

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low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the
temperature of chilled water. The above unit is located on the trolley behind front panel.
3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic
expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum
strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure

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gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high
pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy
meter to measure the power consumed either by hater or by compressor.

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54 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
A. A compressor condenser unit placed inside trolley and fitted with
1. R-134a reciprocating compressor
2. Condenser

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3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan
4. A receiver with angle check valve
B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity
placed inside a well insulated wooden box and provided with
5. Evaporator coil

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6. Stirrer
7. Electric heater 230 V, A.C.
8. The sensing bulb of low temperature thermostat.
9. A high temperature thermostat.
10. A Thermometer to measure the chilled water temperature

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C. The front panel on which are mounted the following
11. Capillary expansion tube with isolating valve.
12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator
and isolating valve
13. Drier cum strainer and sight glass

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14. Thermostat at inlet and outlet of both evaporator and condenser
15. Pressure gauge at inlet and outlet of evaporator and condenser
16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out
17. Heat power regulator switch and regulator
18. Energy meter to measure the power consumed either by hater or by compressor.

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55 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.
2. The heater regulator should be switched off whenever not in use. Heating water beyond 40
0
C may lead to

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permanent damage of the entire system. A high temperature cut off thermostat is provided in the water
chiller, to cut off the heater beyond 30
0
C.Check the setting of the same before operation.
3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.

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4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.
5. The solenoid thermostat is adjusted to cut at 15
0
C and cut in at 10
0

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C of the chilled water. Do not alter the
same.
6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.
7. The space near the condenser should permit good ventilation to aid proper fan performance.
8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked

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in
0
F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,
calibrated in SI units, are not available.)
9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to

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obtain the pressure in MN/m
2
.e.g. P = x psig
= (x + 14.7) psia
= (x + 14.7) / 145 MN/m

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2
(MPa)
10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.
Formulae used:
Let, State 1 indicates the entry of compressor.

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State 2 indicates the exit of compressor.
State 3 indicates the exit from condenser.
State 4 indicates the entry to evaporator
P = Pressure (bar)
T = Temperature (

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0
C)
H = Specific enthalpy (kJ/kg)
v = Specific Volume (m
3

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/Kg)
n = Number of revolutions of energy meter disc.
t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)
t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)
K = Energy meter constant = 3200 lmp / kWh

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N = Speed of compressor = 2840 rpm
h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

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h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2
h3 = Specific enthalpy at Pc and T3 (kJ/kg)
h4 = h3
Stroke volume of compressor = (?/ 4) d
2

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l = 12.58 x 10
-6
m
3

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1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar
2. Average condenser pressure, Pc = (P2 + P3) / 2 bar
3. Heater input, Qe = (n / t1) x (3600 / k) kW
4. Compressor input, W = (n / t2) x (3600 / k) kW
5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1

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6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)
7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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57 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I


Sl.

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No.

Initial
Temp.
of water

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Final
Temp.
of water
Duration

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of exp.

Delivery
pressure

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Delivery
Temp.

Condense
Outlet

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Pressure

Condense
Outlet
Temp.

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Pressure
after
throttling

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Temp.
After
Throttli
ng

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Suction
pressur
e
Suction

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Temp.

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Time for
10 rev. of
compress
or energy
meter

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Height
of water

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in the
vessel

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58 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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Load Test with Capillary tube as expansion device:
1. Fill the chilled water calorimeter with pure water so that the evaporative coils are
fully immersed.
2. Select the capillary tube line by opening the shut-off valve on this line and closing
the one on the thermostatic expansion valve line. The solenoid switch is switched OFF.

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3. Start the compressor and run for some time so that the chilled water temperature
is lowered to the given test temperature.
4. Switch on the heater and slowly increase the power.
5. Allow The temperature in water calorimeter to reach the equilibrium
temperature.

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6. Connect energy meter to motor and heater by the selector switch one after another
and note down the time taken for 10 pulses of the energy meter disc.
7. Note down the pressure and temperature readings at locations 1,2,3 & 4 as
mentioned.
8. Switch OFF the heater and the mains.

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Result:
The load test on a refrigeration test rig was conducted and the results are as follows.
1. Actual C.O.P. of the system =____________.
2. Rhetorical C.O.P. of the system = ___________.
3. Volumetric Efficiency = ___________.

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Outcome:
From this experiment, conducting the load test on a refrigeration test rig and finding out the
volumetric efficiency and co-efficient of performance for any type of refrigerant is learnt and this experiment
could be used in the areas such as Refrigerator and Air Conditioning.

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Applications:
Refrigerator, Air Conditioning.

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59 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? COP
2. Which thermodynamic cycle is used in air conditioning of airplanes using air as refrigerant?
3. Define ? Ton of Refrigeration
4. What is meant by refrigeration?
5. What is meant by air conditioning?

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6. What are the four important properties of a good refrigerant?
7. How does the actual vapour compression cycle differ from that of the ideal cycle?
8. Name any four commonly used refrigerants.
9. What are the expansion devices used in a vapour compression plant?
10. Why throttle valve is used in place of expansion cylinder for vapour compression refrigerant machine?

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11. What are the merits of air refrigeration system?
12. What are the demerits of air refrigeration system?
13. Define ? Refrigerant
14. What is net refrigerating effect of the refrigerant?
15. What are the methods to obtain sub cooling of refrigerant?

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Viva ? voce

60 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.12 EXPERIMENTS ON PSYCHROMETRIC PROCESS

Aim:
To conduct an experiment on psychrometric processes with air conditioning system
Apparatus required:

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(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Digital anemometer
(v) Experimental setup

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Description:
The test rig consist of
1. An air duct support of stand
2. A blower to set up air flow through the duct along with a speed control to vary the
velocity of air.

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3. A heater to rise the air temperature with regulator and energy meter.
4. Water spray, collecting tray, reservoir with gauge pump.
5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.
(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after cooling coil).
6. The test rig consist of compressor, condenser unit placed inside trolley and fitted

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with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for
condenser and (iv) Liquid receiver.
7. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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61 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I

Precautions:
1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence

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avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kw only for the motor
circuit.
2. Natural air currents in the room if in the direction of air duct may defect the experimental results and
hence the duct should be placed such that no wind from doors, windows, fan and cooling air from
other test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan

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and should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase
beyond 240 psi.
3. Never exceed dry bulb temperatures of 40
0
C after the heater (station 2) otherwise the air duct may be

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damaged.
4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may
exceed its maximum of 32
0
C and calibration may be affected.

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5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not
running this will lead to rise in temperature at the heater and may damage the heater and the air duct.
6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their
duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.
7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer

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is placed inside the reservoir at the top. This may have to the cleaned when necessary.
8. Do not open the gate valve fully otherwise water may be splashed outside and the waster
measurement may be in error.
S.
N

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o
Inlet temp
Outlet
temp
Pressu

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re
P1
Tem
p.
T1

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Pressu
re
P2
Temp.
T2

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Pressu
re
P3

Tem

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p.
T3


Pressu

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re
P4


Temp.

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T4
Energy
for 10
revolutio
ns

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Twet Tdry Twet Tdry Lb/in
o
C Lb/in
o
C Lb/in

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o
C Lb/in
o
C

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62 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

9. If the low pressure cut out comes in to action, it means that the Freon charge is insufficient and may
have to be filled up. The suction pressure should never go below 2 psi as otherwise the compressor

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seals will be damaged and air and moisture may enter the system.
10. The refrigerant strainer placed on the front panel should always be warm. If it cools and moisture
condenser on it, then the strainer might have to be charged by an experienced refrigeration
mechanics.
11. The refrigerating system can work continuously for 2 hours, however if the room temperature is above

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25
0
C the condenser may be heated up and the delivery pressure may rise. Do not exceed 240 psi.
Pour one or two glasses of drinking water over the fins of the condenser in order to reduce the
delivery pressure.

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12. After some months of operation the compressor may have to be topped up with oil and some quantity
of Freon-22 may have to be charged by an experienced mechanics.
13. See that distilled water is filled up in the plastic dishes provided under the wet bulb thermometers and
that the wicks are in tact otherwise erroneous readings may be obtained. These thermometers will
show correct readings only when the fan is in operation.

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14. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

Formulae used:
1. Corresponding to the dry and wet bulb temperature at all the stations obtain the specific enthalpy and

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specific humidity values from psychrometric chart.
i.e., h1 and w1 at tb1 and tw1 and so on.
2. Air flow rate, ma = (A x V) / v4 Kg / sec
Where, A = Area of duct at outlet in m
2

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(0.46 m x 0.086 m)
V = Air velocity ( m / sec)
V4 = Specific volume of moist air at station 4 using psychometric chart m
3
/Kg

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3. Moisture added from psychrometric chart, mw1 = ma (w3-w2) Kg / sec.
Where, w3 = Specific humidity at station 3
w2 = Specific humidity at station 2
4. Cooling effect produced on air, Qe = ma (h3 ? h4) kW.
Where, h3 = Specific enthalpy at state 3 kJ/kg

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h4 = Specific enthalpy at state 4 kJ/kg
5. Moisture condensed, mcl = ma (w3 ? w4) kg/sec
Where, w3 = Specific humidity at station 3
w4 = Specific humidity at station 4

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63 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Fill water in the wet bulb temperature probe trays.
2. Start the main.

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3. Start the blower and run it the required speed by keeping the speed regulator at
position.
4. Start the spray pump and open the gate valve suitably.
5. Start the heater.
6. Select the expansion device (Capillary tube / Thermostatic expansion valve)

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7. Start the cooling compressor.
8. Wait for some time till thermometers shown practically constant readings and note down the
following readings:
(i) Dry bulb temperatures tdb1, tdb2, tdb3, tdb4.
(ii) Wet bulb temperatures twb1, twb2, twb3, twb4.

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(iii) Spray water temperature, ts
(iv) Surface temperature of cooler, tm ( at control panel)
(v) Pressure gauge reading, pd ( at control panel)
(vi) Compound gauge reading, Ps ( at control panel)
(vii) Level reduction?l? in spray reservoir (mm) during 5 min.

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(viii) Amount of condensate collected ?lc?, in a measuring jar at cooler tray during a
run of 5 minutes at constant conditions.
(ix) Time in second ?SH? for 10 pulses of the energy meter disc connected to the
heater.
(x) Time in seconds Sc for 10 pulses of the energy meter disc connected to cooler

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compressor.
Result:
Experiment on psychrometric processes with air conditioning system was drawn
Outcome:
From this experiment, conducting the test on psychrometric processes with air

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conditioning system is learnt and this experiment could be used in all types of air conditioning systems.

Applications:
Air Conditioning.

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64 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the commonly used unit of refrigeration?
2. Distinguish between summer air conditioning and winter air conditioning.
3. Define ? RSHF Line
4. Define ? By Pass Factor of a Heating Coil

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5. What is the effect of sub cooling a refrigerant in a vapour compression cycle?
6. What is the function of analyzer and rectifier in an absorption system?
7. What is the purpose of generator assembly in vapour absorption refrigeration system?
8. State the substance used in the Lithium Bromide system and their functions.
9. Differentiate wet compression from dry compression.

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10. Define ? Apparatus Dew Point
11. What is meant by dew point temperature?
12. Define ? Wet Bulb Temperature
13. Define ? Degree of Saturation
14. What is meant by specific humidity?

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15. Define ? Relative Humidity

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Viva ? voce

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65 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.13

PERFORMANCE TEST ON A RECIPROCATING

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AIR COMPRESSOR

Aim:
To conduct a load test on the 2 - stage reciprocating air compressor to determine the isothermal and
volumetric Efficiencies at various delivery pressures

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Apparatus required:
* Air compressor with accessories.
* Stop watch.
Description:

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Two stage air compressors is a reciprocating type driven by a prime mover. The test rig consist of a base on
which the tank is mounted. The outlet of the compressor is connected to the receiver. The suction is
connected to air tank with a calibrated orifice plate through a water manometer. The input to the motor is
recorded by an energy meter. The temperature and pressure of the air compressed is indicated by a
thermometer and pressure gauge.

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Specifications:
1. Air compressor:
* LP Bore, DLP = 63.0 mm.
* HP Bore, DHP = 79.0 mm.
* Stroke, L = 80.0 mm.

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* Speed, N = 1440 rpm (5 HP)
* Effective radius = 0.193 m
2. Air receiver capacity = 0.33 m3
3. Orifice, diameter, d0 = 12 mm
4. Orifice area,. A0 : ?d0

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2
/ 4 = ----------- m
2

5. Coefficient of discharge C d. = 0.6

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6. Energy-meter constant = 200 rev / kWh

66 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

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Observation Table: II
Sl.
No.
Actual

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Discharge
Va
Theoritical
Discharge
Vt

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Volumetric
Efficiency
?
Power
Input

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Output
Power

Overall

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Efficiency
?0
Isothermal
Workdone
IwD

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Polytropic
Workdone
PwD
Isothermal
Efficiency

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?iso
m
3
/sec m
3

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/sec % kW kW % J/Kg J/Kg %


Sl.
No.

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Pressure
p
Manometer
h1
Manometer

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h2
Time for 5 revolutions Energy meter Speed of the compressor Temperature
T1
Temperature
T1

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Kg/cm
2
Cm cm sec rpm
o
C

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o
C

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67 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Check whether manometer is filled with water up to the required level.
2. The maximum pressure in the receiver tank should not exceed 12 kg / cm

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2

Procedure:
1. Ensure that gauge pressure in the tank is zero.
2. Start the compressor. Read the receiver pressure gauge for a particular pressure.

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3. Maintain the pressure constant by adjusting the outlet valve.
4. Note down the manometer reading and time taken for 3 revolution of the energy
Formulae used:
1. Density of air at RTP:
? RTP = ? NTP X 273 Kg/ m

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3

(273 + Room Temp)
Where density of air at NTP = 1.293 Kg/ m
3

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.

2. Air head causing flow:
ha RTP = (h1 - h2) x ? water m
?a RTP

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Where,
(h1- h2) = Difference in manometer liquid, in m.

3. Actual volume at RTP:
Va RTP = C.d x Ao x ? 2 g ha RTP

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Where,
C d= Coefficient of discharge = 0.6.
A o = Area of orifice = ?(d0)
2
m

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2
.
4
Diameter of orifice d o = 0.01 m.
4. Actual volume at NTP:

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Va NTP = VaRTP x T NTP
T RTP
Where,
T NTP = Normal temp - 273
o

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k
T RTP = Room temp -
o
c (273 + TROOM )

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68 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

5. Theoretical Volume of air: (at intake conditions)
V T = ?D
2

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x L x Nc m
3
/ sec.
4 x 60
D = LP Bore diameter = 88.5 mm.

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L = Stroke length = 88.9 mm.
Nc = Compressor speed rpm.
6. Volumetric Efficiency:(for LP stage)
?vol = Va NTP x 100%
Vt

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7. Shaft Input through Energy meter:

= 1 x n x ?t x ?m x 3600 kw.
( Ec x t )
Where,

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Ec = Energy meter constant = 200 rev / kWh
?t = Efficiency for transmission = 0.95.
? m = Efficiency for motor = 0.90.
t = Time for 'n' revolution of energy meter disc.
n = no. of rev. of Energy meter disc.

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8. Isothermal power:
= Pa x Va RTP x log e (R) W
1000
Pa = Atmospheric pressure in N/ m

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2
= 1.01325 x 10
5
N / m
2

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.
R = (Pressure gauge reading + atmospheric pressure)
atmospheric pressure.
9. Isothermal efficiency:
? ISO = Isothermal power x 100%

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Shaft input

Result:
The values of isothermal and volumetric efficiency at various delivery pressures have been studied &
graph between Pressure Vs Volumetric efficiency and Pressure Vs Isothermal efficiency are drawn.

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69 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Outcome:

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From this experiment, conducting the load test on two stage reciprocating air compressor for
determining the isothermal and volumetric Efficiencies at various delivery pressures is understood and this
experiment could be used in the areas such as Refrigerator, Air Conditioning, IC engines, etc.

Applications:

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Refrigerator, Air Conditioning, IC engines.


1. How are air compressors classified?
2. Define ? Isothermal Efficiency of Air Compressor

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3. What is meant by FAD (Free Air Delivery)?
4. What is meant by perfect inter-cooling?
5. Define ? Clearance Ratio of an Air Compressor
6. List out the applications of compressed air.
7. What are the types of air compressors?

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8. What is meant by single acting compressor?
9. What is meant by double acting compressor?
10. What is meant by single stage compressor?
11. What is meant by multi stage compressor?
12. Indicate the applications of reciprocating compressors in industry>

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13. Define ? Mechanical Efficiency
14. What is meant by compression ratio?
15. What are the factors that affect the volumetric efficiency of a reciprocating compressor?

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Viva ? voce

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70 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.14

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PERFORMANCE TEST IN A HC REFRIGERATION
SYSTEM


Aim:

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To conduct the performance test on Vapour Compression Refrigeration System and to determine the
Coefficient of Performance using solenoid valve by throttling method

Description:

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In this system the working fluid is a HC out of a refrigeration system. The HC compression system is most
important system from the view point of commercial and domestic utility. The HC refrigerant at low temp and
pressure enters the reciprocating compressor, where it is compressed isentropically and subsequently its temp
and pressure increases considerably. This HC after leaving the compressor enters the condenser where it is

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cooled into low temperature. Then it is sucked by reciprocating compressor and is thus repeated.
Formula used:

Actual COP = refrigerant effect
I/p energy to compressor

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Refrigerant effect = mxCpx ? T
t
m - mass of water (kg)
Cp - Sp. Heat of water (4.2 kJ/kg K)
?T ? decrease in temp (Ti-Ts)

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t - timetaken duration of expt (sec)

Energy input =n x 3600 /k x t
n ? number of revolutions in energy meter
t ? time taken of ?n? revolutions

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k ? energy meter constant (3200)


71 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulation:

Pressure of the refrigerant (Mpa) Temperature Time for n?
rev of
energy

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meter in
sec
P1 P2 P3 P4 Circulating fluid
temp
Refrigerant temp

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Ti Tf T1 T2 T3 T4

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72 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Model calculation:

Actual COP = refrigerant effect
I/p energy to compressor

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Refrigerant effect = mxCpx ? T
t
m - mass of water (kg)
Cp - Sp. Heat of water (4.2 kJ/kg K)
?T ? decrease in temp (Ti-Ts)

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t - time taken duration of experiment (sec)
Refrigerating effect = 8x4.2x (27-6)/1200=0.588 kw

Energy input = n x 3600
n ? Number of revolutions in energy meter

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t ? Time taken of ?n? revolutions
k ? Energy meter constant
=3 x 3600/(1200 x 54)
=0.166 kW
Actual COP = refrigerant effect

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I/p energy to compressor
= 0.588/0.166
=3.526
Result:

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The experiment was conducted successfully and coefficient of performance was found out is _______.

Outcome:
From this experiment, conducting the performance test on Vapour Compression Refrigeration
System and to determine the Coefficient of Performance using solenoid valve by throttling method is

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understood and this experiment could be used in the areas such as Refrigerator and Air Conditioning systems.
Applications:
Refrigerator, Air Conditioning.

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73 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the difference between air conditioning and refrigeration?
2. Write any three important properties of a good refrigerant.

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3. What is the function of analyzer and rectifier in an absorption system?
4. How does humidity affect human comfort?
5. What is the commonly used unit of refrigeration?
6. Distinguish between summer air conditioning and winter air conditioning.
7. Define ? RSHF Line

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8. Define ? By Pass Factor of a Heating Coil
9. What is the effect of sub cooling a refrigerant in a vapour compression cycle?
10. What is the function of analyzer and rectifier in an absorption system?
11. What is the purpose of generator assembly in vapour absorption refrigeration system?
12. State the substance used in the Lithium Bromide system and their functions.

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13. Differentiate wet compression from dry compression.
14. Define ? Apparatus Dew Point
15. What is meant by dew point temperature?
16. Define ? Wet Bulb Temperature
17. Define ? Degree of Saturation

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18. What is meant by specific humidity?
19. Define ? Relative Humidity
20. What is meant by dew point temperature?

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Viva ? voce

74 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.15

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PERFORMANCE TEST IN A FLUIDIZED BED
COOLING SYSTEM

Aim:

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To determine the performance test on cooling tower
Introduction:
The cooling tower is one of the most important device in chemical industries for example when the hot
water come from heat exchanger we use the cooling tower to cool it The purpose of cooling tower is to cool
relatively warm water by contacting with unsaturated air. The evaporation of water mainly provides cooling. In

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typical water cooling water tower warm water flows countercurrent to an airstream. Typically, the warm water
enters the top of the packed tower and cascades down through the packing , leaving at the bottom Air enters
at the bottom of the tower and flows upward through the descending water . The tower packing often consist of
slats of plastic or of packed bed. The water is distributed by troughs and overflows to cascade over slat
gratings or packing that provides large interfacial areas of contact between the water and air in the form of

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droplets and films of water. The flow of air upward through the tower can be induced by the buoyancy of the
warm air in the tower (natural draft) or by the action of a fan . The water cannot be cooled below the wet bulb
temperature. The driving force for the evaporation of water is approximately the vapour pressure of the water
less the vapour pressure it would have at the wet bulb temperature
Procedure:

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1. Introduce water and record its flow rate.
2. Switch ON the heaters on so that water is heated to the required temperature.
3. Introduce air and record its flow rate.
4. Wait for steady state then record steady state dry and wet bulb temperature of air at the entrance and
exit.

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5. Record the inlet and outlet temperature and flow rate of water also record temperature at different
stages.
Tabulation:

Sl.No. T1 (

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0
c) T2 (
0
c) T3 (
0

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c) Efficiency

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T1 = room temperature

75 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

T2 = water inlet

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T3 = water outlet

Efficiency of cooling tower

ECT = T3/T2/*100

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Model calculation:

Efficiency of cooling tower = water outlet
--------------- *100

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Water inlet

= 36/40 *100

= 90

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Result:
The performance test in cooling tower is determined as ______%.
Outcome:
From this experiment, conducting the performance test on cooling tower is understood and this
experiment could be used in various power plants where cooling tower is used.

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Applications:
Power Plant Cooling Tower, Cooling Tower.


1. What are functions of a draught system?

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2. What are the advantages of burning coal in pulverized form?
3. What are the functions of cooling tower?
4. What are the different types of draught system?
5. What are the methods used for handling of coal?
6. What is meant by fluidized bed combustion?

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7. What is the use of fluidized bed boiler?
8. What are the types of fluidized bed boiler?
9. State the purpose of condenser in fluidized bed boiler.
10. What is meant by pulveriser and why it is used?
11. State the disadvantages of pulverized coal firing.

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12. Distinguish between fouling and slagging.
Viva ? voce

76 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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ADDITIONAL EXPERIMENTS
BEYOND THE SYLLABUS

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77 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.16 AIR CONDITIONING TEST RIG

Aim:

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To conduct a performance test on air conditioning test rig and determine the Coefficient of Performance of
air conditioning system
Apparatus required:
(i) Thermometer
(ii) Electric Heater

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(iii) Stop watch
(iv) Digital anemometer
(v) Experimental setup
Description:
The test rig consist of

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1. An air duct support of stand
2. A blower to set up air flow through the duct along with a speed control to vary the
velocity of air.
3. A heater to rise the air temperature with regulator and energy meter.
4. Water spray, collecting tray, reservoir with gauge pump.

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5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.
(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after
cooling coil).
6. The test rig consists of compressor, condenser unit placed inside trolley and fitted
with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan

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for condenser and (iv) Liquid receiver.

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Observation Table: I

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Air conditioning Test Rig

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Sl.

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No

Inlet
temperat
ure

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Outlet
temperatu
re

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Pressu
re
P1

Tem

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p.
T1

Pressu
re

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P2
Temp.
T2

Pressu

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re
P3

Tem
p.

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T3


Pressu
re

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P4


Tem
p.

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T4

Energy for
10
revolutions

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Twet Tdry Twet Tdry Lb/in
o
C Lb/in
o
C Lb/in

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o
C
Lb/in
o
C

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Precautions:
1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence
avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kW only for the motor circuit.
2. Natural air currents in the room if in the direction of air duct may defect the experimental results and
hence the duct should be placed such that no wind from doors, windows, fan and cooling air from other

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test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan and
should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase beyond
240 psi.
3. Never exceed dry bulb temperatures of 40
0

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C after the heater (station 2) otherwise the air duct may be
damaged.
4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may
exceed its maximum of 32
0

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C and calibration may be affected.
5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not
running this will lead to rise in temperature at the heater and may damage the heater and the air duct.
6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their
duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.

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7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer is
placed inside the reservoir at the top. This may have to the cleaned when necessary.
8. Do not open the gate valve fully otherwise water may be splashed outside and the waster measurement
may be in error.
9. If the low pressure cut out comes in to action, it means that the Freon charge is insufficient and may have

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to be filled up. The suction pressure should never go below 2 psi as otherwise the compressor seals will
be damaged and air and moisture may enter the system.
10. The refrigerant strainer placed on the front panel should always be warm. If it cools and moisture
condenser on it, then the strainer might have to be charged by an experienced refrigeration mechanics.
11. The refrigerating system can work continuously for 2 hours, however if the room temperature is above

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25
0
C the condenser may be heated up and the delivery pressure may rise. Do not exceed 240 psi. Pour
one or two glasses of drinking water over the fins of the condenser in order to reduce the delivery
pressure.

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12. After some months of operation the compressor may have to be topped up with oil and some quantity of
Freon-22 may have to be charged by an experienced mechanics.

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80 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Corresponding to the dry and wet bulb temperature at all the stations obtain the specific enthalpy and

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specific humidity values from psychometric chart.
i.e., h1 and w1 at tb1 and tw1 and so on.
2. Air flow rate, ma = (A x V) / v4 kg / sec
Where, A = Area of duct at outlet in m
2

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(0.46 m x 0.086 m)
V = Air velocity ( m / sec)
V4 = Specific volume of moist air at station 4 using psychometric chart m
3
/kg

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3. Heat added, Q1 = ma (h2 ? h1) kW
Where, h1 = Specific enthalpy at station 1 kJ/kg
h2 = Specific enthalpy at station 2 kJ/kg

4. Moisture added from psychrometric chart, mw1 = ma (w3-w2) Kg / sec.

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Where, w3 = Specific humidity at station 3
w2 = Specific humidity at station 2
5. Compressor power, W = (n / t) x (3600 / k) kW.
Where, n = No. of pulses of energy meter disc
t = Time taken for ?n? no. of pulses (sec)

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k = Energy meter constant (3200 lmp / kW-hr)
6. Actual C.O.P = Cooling effect produced on air / Compressor power.
7. Cooling effect produced on air, Qe = ma (h3 ? h4) kW.
Where, h3 = Specific enthalpy at state 3 kJ/kg
h4 = Specific enthalpy at state 4 kJ/kg

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8. Moisture condensed, mcl = ma (w3 ? w4) Kg/sec
Where, w3 = Specific humidity at station 3
w4 = Specific humidity at station 4
9. Draw the psychrometric process.

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Procedure:
1. Fill water in the wet bulb temperature probe trays.
2. Start the main.
3. Start the blower and run it the required speed by keeping the speed regulator at position.
4. Start the spray pump and open the gate valve suitably.

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5. Start the heater.

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6. Select the expansion device (Capillary tube / Thermostatic expansion valve)

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7. Start the cooling compressor.
8. Wait for some time till thermometers shown practically constant readings and note down the following
readings:
(ii) Dry bulb temperatures tdb1, tdb2, tdb3, tdb4.
(ii) Wet bulb temperatures twb1, twb2, twb3, twb4.

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(xi) Spray water temperature, ts
(xii) Surface temperature of cooler, tm ( at control panel)
(xiii) Pressure gauge reading, pd ( at control panel)
(xiv) Compound gauge reading, Ps ( at control panel)
(xv) Level reduction?l? in spray reservoir (mm) during 5 min.

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(xvi) Amount of condensate collected ?lc?, in a measuring jar at cooler tray during a
run of 5 minutes at constant conditions.
(xvii) Time in second ?SH? for 10 pulses of the energy meter disc connected to the
heater.
(xviii) Time in seconds Sc for 10 pulses of the energy meter disc connected to cooler

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1. Repeat the above procedures for four more different settings of the fan Regulator (Position 1,2,3,4 & 5). If
sensible cooling range is narrow, then switch off the spray and repeat as above. If the atmosphere is cool,
the heater may be set for greater dissipation. If more readings are required for cooling below dew point

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and dehumidification switch off heater and repeat procedure.
Result:
The Load test on the AIR CONDITIONING TEST RIG was conducted and the results are as follows.
1. Actual C.O.P of the system = ______________.
Outcome:

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From this experiment, conducting the performance test on air conditioning test rig and
determining the Coefficient of Performance of air conditioning system is understood and this experiment could
be used in the areas such as Refrigerator and Air Conditioning systems.
Applications:
Refrigerator, Air Conditioning.

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FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?

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DEPARTMENT OF
MECHANICAL ENGINEERING

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ME6512 ? THERMAL ENGINEERING LABORATORY

V SEMESTER - R 2013

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Name : _______________________________________
Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart

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and soul


DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION

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VISION
MISSION
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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

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1. Fundamentals
To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence

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To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them
3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design

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products requiring interdisciplinary skills
4. Professional skills
To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies

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5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering
and to create awareness about the need for lifelong learning and pursuing advanced degrees

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PROGRAMME OUTCOMES (POs)

On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering

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2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship
3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools

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6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical
environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms

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9. To work in a team as a team member or a leader and make unique contributions and work with
coordination
10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

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LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:
1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder

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4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall
6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant

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9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system

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12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor
14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection

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experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus
5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.

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8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.
10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.

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12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at
various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC

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Boiler.



COURSE OBJECTIVES

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COURSE OUTCOMES
7 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

CONTENTS

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Sl.No.
Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS

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1 Thermal conductivity measurement using guarded plate apparatus 6
2
Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11

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3
Determination of heat transfer coefficient under natural convection from a
vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21

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5
Determination of thermal conductivity of composite wall 27
CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31

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7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34
8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47

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CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51
12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14

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Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72
ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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Expt. No.1

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THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate

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method
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters

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together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.
Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples

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No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts
on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

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Formulae used:
1. Power input, Q = V ? A / 2 W
2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2

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(10 + x)

cm
2

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4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:
1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help

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of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do
not disturb the thermocouples terminals and heater wires.

Specifications:

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1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm
3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm

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6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm
8. Mean temperature range = 40
0
C ? 100

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0
C
9. Maximum temperature of the hot plate = 170
0
C

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10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)
12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V

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15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)
17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0

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C
19. Width of gap between two heater plates (x) = 2.5 mm
20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter
V

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Ammeter
A
Main heater (
0
C) Test Plate (

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0
C)
T1 T2 T3 T4 T5 T6

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Schematic view of the test set-up:


Procedure:

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1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.
2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single

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phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.
5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.

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8. Take the final steady state values for calculations.

Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

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Outcome:
From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

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Applications:
Pipe lines, IC engines, heat exchangers

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12 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.

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3. State the applications of fins.
4. Define ? Fins
5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?

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8. What are the various modes of heat transfer?
9. What is meant by conduction?
10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?

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13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?
15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?

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18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?
20. State the advantages of dimensional analysis.

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Viva ? voce

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13 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.2

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THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE
APPARATUS

Aim:

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To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:
(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple

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(iv) Ammeter
(v) Voltmeter
Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.

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There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

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Specifications:
1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.

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4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

14 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the
experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.

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4. Never exceed 80W
Formulae used:
The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging

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k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.
L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:

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Sl.
No.
Voltage
(V)
Current

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(A)
Heater Temperature
(
0
C)

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Asbestos Temperature
(
0
C)
Saw dust

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Temperature (
0
C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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15 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.
3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos

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layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by
thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:

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The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m
2
-K

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Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe
apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

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Applications:
Exhaust pipe lines, IC engines, heat exchangers

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16 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?
3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)

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6. Define ? Prandtl Number(Pr)
7. Define ? Convection
8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?

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11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?
13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.

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16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?
18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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17 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.3

DETERMINATION OF HEAT TRANSFER

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COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical

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tube losing heat by natural convection
Apparatus required:
(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter

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(iv) Voltmeter
Theory:
The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which

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in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is
measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.

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The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the
relative motion of hot and cold fluid particles.

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18 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Schematic view of the test set-up:

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mm
mm

19 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Diameter of the tube(d) = 40 mm
2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch

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Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300
0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples

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6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V
8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

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Tabulation:
Sl. No.
Voltage Current Temperature of Thermocouple (
0
c)

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V A
T1 T2 T3 T4 T5 T6

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20 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}

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Where, h = average surface heat transfer coefficient W/m
2
K
As = Area of heat transfer surface = ? x d x l m
2

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Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7
0
C
q = heat transfer rate W

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Ta = T8 Ambient temperature in duct (
0
C) ?
2. hL / k = A { g L
3

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?T Cp ?/2v
2
}
n

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Where, hL / k are called Nusselt Number.
L
3
g?T / v
2

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is called Grashof number.
?Cp / k called Prandtl Number.
A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid

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v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid
Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity

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?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)
0
K
-1

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Where Tf = (Ts + Ta )/ 2

For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.

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hL / k = 0.56 (Gr.Pr)
0.25
for 10
4
< Gr.Pr.<10

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8

hL / k = 0.13 (Gr.Pr)
1/3
for 10

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8
< Gr.Pr.<10
12
Here, L = Length of the cylinder

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21 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).

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3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).
5. Repeat the experiment at different heat inputs.

Results:

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The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m
2
K
Experimental = ______________ W/ m

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2
K

Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing

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heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be
found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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22 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Grash of Number(Gr)
2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?

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5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness
7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)

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10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?
12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness

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15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.
17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?

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20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

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23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No. 4

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DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION
FROM A TUBE

Aim:

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To determine the heat transfer co-efficient by using forced convection apparatus

Apparatus required:
(i) Experimental setup
(ii) Thermocouples

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(iii) U ? tube manometer

Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air

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stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater
is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of

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orifice meter and the water manometer fitted on the board.


24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

Sl. No. Voltage Current Temperature in (

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0
C)
Manometer
reading of water
in h in meter

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(V) (A)
T1

T2

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T3

T4

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T5

T6

h1

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cm
h2
cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Pipe diameter outside (Do) = 40 mm
2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor

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5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C
7. Temperature Indicator = Range 0 to 300
0
C

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(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V
9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:

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1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.

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6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W
Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.

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2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.
3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

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26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. The rate at which air is getting heated is calculated as

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qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)
Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o

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C)
= T6 ? T1.
2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate

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Q = Cd x (?/4) di
2
?2gH x (?w / ?a) m
3
/hr

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3. ha = qa /A(Ts- Ta) W / m
2
K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m

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2

Ta = Average temperature of air = (T1 + T6)/2
o
C

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Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o
C
Cd = 0.64
H = Difference of water level in manometer m

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?w Density of water = 1000 Kg/m
3

?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

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d = diameter of orifice meter = 0.014 m
g = acceleration due to gravity = 9.81 m/s
2

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using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:
Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2

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)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature
(T1 + T6)/2
o
C

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5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number
K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

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27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k

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? = Viscosity Ns/m
2

k = Thermal conductivity of fluid W/m
2

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K
Nu = 0.023 (Re)
0.8
(Pr)
0.4

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Bulk mean temperature = (T1 + T6)/2

Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.

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hactual = -------------- W/m
2
K
htheoritical = -------------- W/m
2

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K

Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?

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3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.
5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?

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8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.
10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection

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13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?
15. Define ? Momentum Thickness

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Viva ? voce

29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

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Aim:
To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,

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the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different
materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure

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temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A
channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat

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flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in
series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm

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2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm
4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.

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2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.
3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

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30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature

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gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as
Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:

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Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3
Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R

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Tabulation:
Sl.No. Voltmeter
reading
(V)
Ammeter

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reading
(A)
T1
(
0

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C)
T2
(
0
C)

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T3
(
0
C)
T4

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(
0
C)
T5
(

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0
C)
T6
(
0

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C)
T7
(
0
C)

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T8
(
0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Composite wall apparatus set-up

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Result:
The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W

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c. Asbestos section = ------------W

Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure

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Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Heat Transfer
2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?

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5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?
6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.

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9. What is meant by effectiveness?
10. Define ? Heat Exchanger
11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

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33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.6

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DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

Aim:
To find out the thermal conductivity of insulating powder by conduction

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Apparatus required:

The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A

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multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input
power and dimmer stat is provided to vary the input power.

Procedure:

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1. Switch on the unit and adjust the input power to the required extent.
2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.

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5. Repeat the experiments for different power inputs.


The readings are tabulated below

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Sl.No. Voltmeter
reading( V)
Ammeter
reading (A)
T1

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(
0
C)
T2
(

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0
C)
T3
(
0

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C)
T4
(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm

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The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the
inner sphere, and the outer sphere respectively.

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34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Fig. 1 Apparatus of thermal conductivity of insulating powder

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[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

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Outcome:

From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam

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boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity

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3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?
5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.

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8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?
10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?

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13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)
15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?

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18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?
20. What is meant by steady state heat conduction?

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Viva ? voce

36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

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HEAT TRANSFER FROM PIN-FIN APPARATUS
(NATURAL AND FORCED CONVECTION MODES)

Aim:

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To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is
connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is

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measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.
Tabulations:
Forced convection:
Sl.

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No.
V I

Fin Temperatures (
0

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C)
Ambient Temp
(
0
C)

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Manometer
Reading
(V)

(A)

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T1 T2 T3 T4 T5 T6 T7 T8
h1
cm
h2

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cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Duct size = 150 mm x 100 mm.

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2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm
4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

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Schematic view of the test set-up:



zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm
7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5

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10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.
0
C
12. Temperature indicator = 0 ? 300

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0
C
(With compensation of ambient temperature up-to 50
0
C)

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13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)
15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8

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Brass Pin Fin
Heater

38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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16. Ammeter = 0 ? 2 A
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.

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4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:

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Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,
100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.

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4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.
5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2

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Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)
2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m

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3
/s.
Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m

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3

?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s

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2

Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s

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Where Q = discharge of air

39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

A = area of the duct

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4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number
Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.

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(T1 + T6) / 2
o
C
5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number

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6. Nusselt Number:
Nu = CRe
m
(Pr)
0.33

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7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,
Where, p = perimeter in m
k= 386 w/mk
m= ?(hp/kA)

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A = area of fin = (? x D
2
) /4
L = Length of the fin
Tw ? average temperature

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T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL
Results:
Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________

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Heat transfer, Q = ___________ W

Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,

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Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.


40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Extended Surface
2. What is meant by convective mass transfer?
3. State the applications of fins.
4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer

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6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?
8. Define ? Conduction
9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?

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11. Define ? Convection
12. What is meant by transient heat conduction?
13. What is meant by radiation?
14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.8

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DETERMINATION OF STEFAN ? BOLTZMANN
CONSTANT

Aim:

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To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch

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(iv) Geyser water
Theory:
The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water

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between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a
hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.

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When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.
Specifications:
1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere

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3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm
5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg

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8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0
C
= (or) 0.1 Kcal / kg
0

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C
9. No. of thermocouples mounted on B = 4 Nos.
10. No. of thermocouples mounted on D = 1 No.

42 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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11. Temperature indicator digital 0.1
0
C L.C 0 - 200
0

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C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.
12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water
Precautions:

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Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4

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? Td
4
)
Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)

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Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

Schematic view of the test set-up:

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Heater

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43 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulations:
Proc
edur

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e:
1. H
eat the
water
in the

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tank by
the immersion heater up to a temperature of about 90
0
C.
2. Remove the disc, D before pouring the hot water in the jacket.

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3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling
the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.

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6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m

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2
k
4
.

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Outcome:

From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using

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boltzman apparatus.
.Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

Sl. No.

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Hemisphere Temperature(
0
C) Avg. Temp.
of the
Hemisphere

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(Th)
T4
Steady
Temp. of
Disc

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T0 (Td)
Time
(Sec) T1 T2 T3

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44 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? Emissive Power[E]
2. What are meant by black body?
3. State Planck?s distribution law.
4. Define ? Biot Number
5. State Wien?s displacement law.

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6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.
8. What are the various types of convection?
9. Define ? Condensation
10. What are the various modes of condensation?

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11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?
13. State Krichoff's law or radiation
14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.9

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DETERMINATION OF EMISSIVITY OF A GREY
SURFACE

Aim:

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To measure emissivity of the test plate surface at various temperature
Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with
heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The

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temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be
determined.
Specifications:
1. Heater input to black plate W1 = V1 x I1 W

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2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)
4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V

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6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V
8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300

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0
C.

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46 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.

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2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.
4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.

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Tabulation:
Sl.
No
Voltage

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Current

Black body
temp(
0

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C)
Avg.
temp.

Polished body

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temp (
0
C)
Avg.
temp.

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Enclosure
Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts

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4
? Ta
4
) A
Eb ? E = (W1 ? W2) / ? (Ts

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4
? Ta
4
) A
E = Eb ? {(W1 ? W2) / ? (Ts

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4
? Ta
4
) A}
Where,

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W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W
A = area of plates = 2 (?/4) xd
2
m

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2

T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)

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Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

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? = Stefan boltzman constant = 5.67 x 10
-8
W/m
2
K

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4


Schematic view of the test set-up:

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Procedure:
1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by

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the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state
condition.

Results:

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The emissivity of the test plate surface is found to be _____________.
Outcome:
From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

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48 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Emissivity
2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?

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4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?
6. What is meant by shape factor?
7. Define ? Radiation
8. What is meant by monochromatic emissive power?

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9. Define ? Emissive Power
10. What is meant by absorptivity?
11. Define ? Black Body
12. What is meant by transmissivity?
13. State Plank's distribution law

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14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

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49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.10

EFFECTIVENESS OF PARALLEL / COUNTER

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FLOW HEAT EXCHANGE

Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:

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(i) Experimental Setup
(ii) Stop watch
(iii) Thermometer
Theory:
Heat exchangers are classified in three categories:

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1. Transfer type
2. Storage type
3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.

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The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.
ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water

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which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by
means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:

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1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm
3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50

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0
C - 2 Nos.
6. Thermometers (for hot water) = 0 ? 100
0
C - 2 Nos.

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7. Measuring flask = 0 ? 1000 CC

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8. Geyser: single phase type to obtain hot water supply

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9. Thermo Cole insulation for outer pipe.
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Tabulations:

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Sl.
No.
Flow Hot Fluid (
0
C) Cold Fluid (

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0
C)
Time for
collection of
hot fluid

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Kg/sec
Time for
collection
of cold fluid
Kg/sec

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1 Parallel flow
Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)

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1. Area of the pipe A = ? (D ? d) L
Where, D = inlet diameter of the outer tube
d = outlet diameter of the inner tube
L = Length of the tube

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2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

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Where, m = mass flow rate Kg/ sec.

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m = ?v/t, ? = density of water and t = time taken for hot water
Cp = Specific heat of capacity 4.187 kJ/kg -K
Thi = Temperature of hot water inlet
Tho = Temperature of hot water outlet

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3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W
Where, m = mass flow rate
Cp = Specific heat of capacity
Tco = Temperature of cold water inlet
Tci = Temperature of cold water outlet

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4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W
Where, Q? = (Qa + Qc) / 2
5. Logarithmic mean temperature difference( L M T D)
?Tm = (?Ti - ?To) / In (?Ti/?To)
Where, ?To = Tho ? Tco

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?Ti = Thi ? Tci
6. Over all heat transfer coefficient
h = Q?/?Tm A W/m
2
K

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where Q? = (Qa + Qc) / 2

Procedure:
1. Place the thermometers in position and note down their readings when they are at room temperature and
no water is flowing at either side. This is required to correct the temperature.

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2. Start the flow on hot water side.
3. Start the flow through annulus and run the exchanger as parallel flow unit.
4. Put ON the geyser.
5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.
6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.

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7. Keeping the flow rates same, wait till the steady state conditions are reached.
8. Record the temperatures on hot water and cold water side and also the flow rates accurately.
9. Repeat the experiment with a counter flow under identical flow conditions.
10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

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52 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Result:
1. The values of effectiveness of heat exchanger were found as

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(i) Parallel flow = ________.
(ii) Counter flow = _________.
2. Over all heat exchanger (heat transfer coefficient)
(i) Parallel flow = ________.
(ii) Counter flow = _________.

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Outcome:
From this experiment, determining the values of effectiveness of parallel and counter flow
heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat
exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Heat Exchanger
2. What are the types of heat exchangers?
3. What is meant by indirect contact heat exchanger?
4. Write about the merits of drop wise condensation.
5. What is meant by film wise and drop wise condensation?

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6. What is meant by effectiveness?
7. Define ? Direct Heat Exchanger
8. What is meant by fouling factor?
9. Distinguish between regenerator and recuperates.
10. What is meant by parallel flow heat exchanger?

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11. What is meant by counter flow heat exchanger?
12. What is meant by cross flow heat exchanger?
13. What is meant by shell and tube heat exchanger?
Viva ? voce

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53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.11

DETERMINATION OF COP OF A REFRIGERATION

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SYSTEM

Aim:
To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration
system

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Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Experimental setup

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Description:
1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a
reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.
2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated
wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a

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low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the
temperature of chilled water. The above unit is located on the trolley behind front panel.
3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic
expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum
strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure

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gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high
pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy
meter to measure the power consumed either by hater or by compressor.

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Specifications:
A. A compressor condenser unit placed inside trolley and fitted with
1. R-134a reciprocating compressor
2. Condenser

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3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan
4. A receiver with angle check valve
B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity
placed inside a well insulated wooden box and provided with
5. Evaporator coil

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6. Stirrer
7. Electric heater 230 V, A.C.
8. The sensing bulb of low temperature thermostat.
9. A high temperature thermostat.
10. A Thermometer to measure the chilled water temperature

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C. The front panel on which are mounted the following
11. Capillary expansion tube with isolating valve.
12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator
and isolating valve
13. Drier cum strainer and sight glass

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14. Thermostat at inlet and outlet of both evaporator and condenser
15. Pressure gauge at inlet and outlet of evaporator and condenser
16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out
17. Heat power regulator switch and regulator
18. Energy meter to measure the power consumed either by hater or by compressor.

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55 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.
2. The heater regulator should be switched off whenever not in use. Heating water beyond 40
0
C may lead to

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permanent damage of the entire system. A high temperature cut off thermostat is provided in the water
chiller, to cut off the heater beyond 30
0
C.Check the setting of the same before operation.
3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.

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4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.
5. The solenoid thermostat is adjusted to cut at 15
0
C and cut in at 10
0

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C of the chilled water. Do not alter the
same.
6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.
7. The space near the condenser should permit good ventilation to aid proper fan performance.
8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked

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in
0
F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,
calibrated in SI units, are not available.)
9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to

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obtain the pressure in MN/m
2
.e.g. P = x psig
= (x + 14.7) psia
= (x + 14.7) / 145 MN/m

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2
(MPa)
10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.
Formulae used:
Let, State 1 indicates the entry of compressor.

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State 2 indicates the exit of compressor.
State 3 indicates the exit from condenser.
State 4 indicates the entry to evaporator
P = Pressure (bar)
T = Temperature (

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0
C)
H = Specific enthalpy (kJ/kg)
v = Specific Volume (m
3

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/Kg)
n = Number of revolutions of energy meter disc.
t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)
t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)
K = Energy meter constant = 3200 lmp / kWh

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N = Speed of compressor = 2840 rpm
h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

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h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2
h3 = Specific enthalpy at Pc and T3 (kJ/kg)
h4 = h3
Stroke volume of compressor = (?/ 4) d
2

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l = 12.58 x 10
-6
m
3

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1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar
2. Average condenser pressure, Pc = (P2 + P3) / 2 bar
3. Heater input, Qe = (n / t1) x (3600 / k) kW
4. Compressor input, W = (n / t2) x (3600 / k) kW
5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1

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6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)
7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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57 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I


Sl.

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No.

Initial
Temp.
of water

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Final
Temp.
of water
Duration

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of exp.

Delivery
pressure

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Delivery
Temp.

Condense
Outlet

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Pressure

Condense
Outlet
Temp.

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Pressure
after
throttling

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Temp.
After
Throttli
ng

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Suction
pressur
e
Suction

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Temp.

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Time for
10 rev. of
compress
or energy
meter

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Height
of water

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in the
vessel

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58 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:

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Load Test with Capillary tube as expansion device:
1. Fill the chilled water calorimeter with pure water so that the evaporative coils are
fully immersed.
2. Select the capillary tube line by opening the shut-off valve on this line and closing
the one on the thermostatic expansion valve line. The solenoid switch is switched OFF.

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3. Start the compressor and run for some time so that the chilled water temperature
is lowered to the given test temperature.
4. Switch on the heater and slowly increase the power.
5. Allow The temperature in water calorimeter to reach the equilibrium
temperature.

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6. Connect energy meter to motor and heater by the selector switch one after another
and note down the time taken for 10 pulses of the energy meter disc.
7. Note down the pressure and temperature readings at locations 1,2,3 & 4 as
mentioned.
8. Switch OFF the heater and the mains.

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Result:
The load test on a refrigeration test rig was conducted and the results are as follows.
1. Actual C.O.P. of the system =____________.
2. Rhetorical C.O.P. of the system = ___________.
3. Volumetric Efficiency = ___________.

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Outcome:
From this experiment, conducting the load test on a refrigeration test rig and finding out the
volumetric efficiency and co-efficient of performance for any type of refrigerant is learnt and this experiment
could be used in the areas such as Refrigerator and Air Conditioning.

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Applications:
Refrigerator, Air Conditioning.

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59 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? COP
2. Which thermodynamic cycle is used in air conditioning of airplanes using air as refrigerant?
3. Define ? Ton of Refrigeration
4. What is meant by refrigeration?
5. What is meant by air conditioning?

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6. What are the four important properties of a good refrigerant?
7. How does the actual vapour compression cycle differ from that of the ideal cycle?
8. Name any four commonly used refrigerants.
9. What are the expansion devices used in a vapour compression plant?
10. Why throttle valve is used in place of expansion cylinder for vapour compression refrigerant machine?

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11. What are the merits of air refrigeration system?
12. What are the demerits of air refrigeration system?
13. Define ? Refrigerant
14. What is net refrigerating effect of the refrigerant?
15. What are the methods to obtain sub cooling of refrigerant?

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Viva ? voce

60 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.12 EXPERIMENTS ON PSYCHROMETRIC PROCESS

Aim:
To conduct an experiment on psychrometric processes with air conditioning system
Apparatus required:

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(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Digital anemometer
(v) Experimental setup

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Description:
The test rig consist of
1. An air duct support of stand
2. A blower to set up air flow through the duct along with a speed control to vary the
velocity of air.

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3. A heater to rise the air temperature with regulator and energy meter.
4. Water spray, collecting tray, reservoir with gauge pump.
5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.
(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after cooling coil).
6. The test rig consist of compressor, condenser unit placed inside trolley and fitted

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with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for
condenser and (iv) Liquid receiver.
7. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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61 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Observation Table: I

Precautions:
1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence

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avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kw only for the motor
circuit.
2. Natural air currents in the room if in the direction of air duct may defect the experimental results and
hence the duct should be placed such that no wind from doors, windows, fan and cooling air from
other test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan

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and should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase
beyond 240 psi.
3. Never exceed dry bulb temperatures of 40
0
C after the heater (station 2) otherwise the air duct may be

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damaged.
4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may
exceed its maximum of 32
0
C and calibration may be affected.

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5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not
running this will lead to rise in temperature at the heater and may damage the heater and the air duct.
6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their
duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.
7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer

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is placed inside the reservoir at the top. This may have to the cleaned when necessary.
8. Do not open the gate valve fully otherwise water may be splashed outside and the waster
measurement may be in error.
S.
N

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o
Inlet temp
Outlet
temp
Pressu

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re
P1
Tem
p.
T1

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Pressu
re
P2
Temp.
T2

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Pressu
re
P3

Tem

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p.
T3


Pressu

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re
P4


Temp.

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T4
Energy
for 10
revolutio
ns

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Twet Tdry Twet Tdry Lb/in
o
C Lb/in
o
C Lb/in

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o
C Lb/in
o
C

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62 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

9. If the low pressure cut out comes in to action, it means that the Freon charge is insufficient and may
have to be filled up. The suction pressure should never go below 2 psi as otherwise the compressor

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seals will be damaged and air and moisture may enter the system.
10. The refrigerant strainer placed on the front panel should always be warm. If it cools and moisture
condenser on it, then the strainer might have to be charged by an experienced refrigeration
mechanics.
11. The refrigerating system can work continuously for 2 hours, however if the room temperature is above

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25
0
C the condenser may be heated up and the delivery pressure may rise. Do not exceed 240 psi.
Pour one or two glasses of drinking water over the fins of the condenser in order to reduce the
delivery pressure.

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12. After some months of operation the compressor may have to be topped up with oil and some quantity
of Freon-22 may have to be charged by an experienced mechanics.
13. See that distilled water is filled up in the plastic dishes provided under the wet bulb thermometers and
that the wicks are in tact otherwise erroneous readings may be obtained. These thermometers will
show correct readings only when the fan is in operation.

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14. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

Formulae used:
1. Corresponding to the dry and wet bulb temperature at all the stations obtain the specific enthalpy and

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specific humidity values from psychrometric chart.
i.e., h1 and w1 at tb1 and tw1 and so on.
2. Air flow rate, ma = (A x V) / v4 Kg / sec
Where, A = Area of duct at outlet in m
2

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(0.46 m x 0.086 m)
V = Air velocity ( m / sec)
V4 = Specific volume of moist air at station 4 using psychometric chart m
3
/Kg

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3. Moisture added from psychrometric chart, mw1 = ma (w3-w2) Kg / sec.
Where, w3 = Specific humidity at station 3
w2 = Specific humidity at station 2
4. Cooling effect produced on air, Qe = ma (h3 ? h4) kW.
Where, h3 = Specific enthalpy at state 3 kJ/kg

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h4 = Specific enthalpy at state 4 kJ/kg
5. Moisture condensed, mcl = ma (w3 ? w4) kg/sec
Where, w3 = Specific humidity at station 3
w4 = Specific humidity at station 4

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63 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
1. Fill water in the wet bulb temperature probe trays.
2. Start the main.

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3. Start the blower and run it the required speed by keeping the speed regulator at
position.
4. Start the spray pump and open the gate valve suitably.
5. Start the heater.
6. Select the expansion device (Capillary tube / Thermostatic expansion valve)

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7. Start the cooling compressor.
8. Wait for some time till thermometers shown practically constant readings and note down the
following readings:
(i) Dry bulb temperatures tdb1, tdb2, tdb3, tdb4.
(ii) Wet bulb temperatures twb1, twb2, twb3, twb4.

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(iii) Spray water temperature, ts
(iv) Surface temperature of cooler, tm ( at control panel)
(v) Pressure gauge reading, pd ( at control panel)
(vi) Compound gauge reading, Ps ( at control panel)
(vii) Level reduction?l? in spray reservoir (mm) during 5 min.

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(viii) Amount of condensate collected ?lc?, in a measuring jar at cooler tray during a
run of 5 minutes at constant conditions.
(ix) Time in second ?SH? for 10 pulses of the energy meter disc connected to the
heater.
(x) Time in seconds Sc for 10 pulses of the energy meter disc connected to cooler

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compressor.
Result:
Experiment on psychrometric processes with air conditioning system was drawn
Outcome:
From this experiment, conducting the test on psychrometric processes with air

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conditioning system is learnt and this experiment could be used in all types of air conditioning systems.

Applications:
Air Conditioning.

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64 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the commonly used unit of refrigeration?
2. Distinguish between summer air conditioning and winter air conditioning.
3. Define ? RSHF Line
4. Define ? By Pass Factor of a Heating Coil

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5. What is the effect of sub cooling a refrigerant in a vapour compression cycle?
6. What is the function of analyzer and rectifier in an absorption system?
7. What is the purpose of generator assembly in vapour absorption refrigeration system?
8. State the substance used in the Lithium Bromide system and their functions.
9. Differentiate wet compression from dry compression.

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10. Define ? Apparatus Dew Point
11. What is meant by dew point temperature?
12. Define ? Wet Bulb Temperature
13. Define ? Degree of Saturation
14. What is meant by specific humidity?

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15. Define ? Relative Humidity

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Viva ? voce

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65 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.13

PERFORMANCE TEST ON A RECIPROCATING

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AIR COMPRESSOR

Aim:
To conduct a load test on the 2 - stage reciprocating air compressor to determine the isothermal and
volumetric Efficiencies at various delivery pressures

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Apparatus required:
* Air compressor with accessories.
* Stop watch.
Description:

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Two stage air compressors is a reciprocating type driven by a prime mover. The test rig consist of a base on
which the tank is mounted. The outlet of the compressor is connected to the receiver. The suction is
connected to air tank with a calibrated orifice plate through a water manometer. The input to the motor is
recorded by an energy meter. The temperature and pressure of the air compressed is indicated by a
thermometer and pressure gauge.

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Specifications:
1. Air compressor:
* LP Bore, DLP = 63.0 mm.
* HP Bore, DHP = 79.0 mm.
* Stroke, L = 80.0 mm.

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* Speed, N = 1440 rpm (5 HP)
* Effective radius = 0.193 m
2. Air receiver capacity = 0.33 m3
3. Orifice, diameter, d0 = 12 mm
4. Orifice area,. A0 : ?d0

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2
/ 4 = ----------- m
2

5. Coefficient of discharge C d. = 0.6

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6. Energy-meter constant = 200 rev / kWh

66 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

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Observation Table: II
Sl.
No.
Actual

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Discharge
Va
Theoritical
Discharge
Vt

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Volumetric
Efficiency
?
Power
Input

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Output
Power

Overall

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Efficiency
?0
Isothermal
Workdone
IwD

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Polytropic
Workdone
PwD
Isothermal
Efficiency

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?iso
m
3
/sec m
3

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/sec % kW kW % J/Kg J/Kg %


Sl.
No.

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Pressure
p
Manometer
h1
Manometer

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h2
Time for 5 revolutions Energy meter Speed of the compressor Temperature
T1
Temperature
T1

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Kg/cm
2
Cm cm sec rpm
o
C

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o
C

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67 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. Check whether manometer is filled with water up to the required level.
2. The maximum pressure in the receiver tank should not exceed 12 kg / cm

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2

Procedure:
1. Ensure that gauge pressure in the tank is zero.
2. Start the compressor. Read the receiver pressure gauge for a particular pressure.

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3. Maintain the pressure constant by adjusting the outlet valve.
4. Note down the manometer reading and time taken for 3 revolution of the energy
Formulae used:
1. Density of air at RTP:
? RTP = ? NTP X 273 Kg/ m

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3

(273 + Room Temp)
Where density of air at NTP = 1.293 Kg/ m
3

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.

2. Air head causing flow:
ha RTP = (h1 - h2) x ? water m
?a RTP

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Where,
(h1- h2) = Difference in manometer liquid, in m.

3. Actual volume at RTP:
Va RTP = C.d x Ao x ? 2 g ha RTP

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Where,
C d= Coefficient of discharge = 0.6.
A o = Area of orifice = ?(d0)
2
m

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2
.
4
Diameter of orifice d o = 0.01 m.
4. Actual volume at NTP:

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Va NTP = VaRTP x T NTP
T RTP
Where,
T NTP = Normal temp - 273
o

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k
T RTP = Room temp -
o
c (273 + TROOM )

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5. Theoretical Volume of air: (at intake conditions)
V T = ?D
2

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x L x Nc m
3
/ sec.
4 x 60
D = LP Bore diameter = 88.5 mm.

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L = Stroke length = 88.9 mm.
Nc = Compressor speed rpm.
6. Volumetric Efficiency:(for LP stage)
?vol = Va NTP x 100%
Vt

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7. Shaft Input through Energy meter:

= 1 x n x ?t x ?m x 3600 kw.
( Ec x t )
Where,

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Ec = Energy meter constant = 200 rev / kWh
?t = Efficiency for transmission = 0.95.
? m = Efficiency for motor = 0.90.
t = Time for 'n' revolution of energy meter disc.
n = no. of rev. of Energy meter disc.

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8. Isothermal power:
= Pa x Va RTP x log e (R) W
1000
Pa = Atmospheric pressure in N/ m

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2
= 1.01325 x 10
5
N / m
2

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.
R = (Pressure gauge reading + atmospheric pressure)
atmospheric pressure.
9. Isothermal efficiency:
? ISO = Isothermal power x 100%

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Shaft input

Result:
The values of isothermal and volumetric efficiency at various delivery pressures have been studied &
graph between Pressure Vs Volumetric efficiency and Pressure Vs Isothermal efficiency are drawn.

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69 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Outcome:

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From this experiment, conducting the load test on two stage reciprocating air compressor for
determining the isothermal and volumetric Efficiencies at various delivery pressures is understood and this
experiment could be used in the areas such as Refrigerator, Air Conditioning, IC engines, etc.

Applications:

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Refrigerator, Air Conditioning, IC engines.


1. How are air compressors classified?
2. Define ? Isothermal Efficiency of Air Compressor

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3. What is meant by FAD (Free Air Delivery)?
4. What is meant by perfect inter-cooling?
5. Define ? Clearance Ratio of an Air Compressor
6. List out the applications of compressed air.
7. What are the types of air compressors?

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8. What is meant by single acting compressor?
9. What is meant by double acting compressor?
10. What is meant by single stage compressor?
11. What is meant by multi stage compressor?
12. Indicate the applications of reciprocating compressors in industry>

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13. Define ? Mechanical Efficiency
14. What is meant by compression ratio?
15. What are the factors that affect the volumetric efficiency of a reciprocating compressor?

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Viva ? voce

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70 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.14

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PERFORMANCE TEST IN A HC REFRIGERATION
SYSTEM


Aim:

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To conduct the performance test on Vapour Compression Refrigeration System and to determine the
Coefficient of Performance using solenoid valve by throttling method

Description:

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In this system the working fluid is a HC out of a refrigeration system. The HC compression system is most
important system from the view point of commercial and domestic utility. The HC refrigerant at low temp and
pressure enters the reciprocating compressor, where it is compressed isentropically and subsequently its temp
and pressure increases considerably. This HC after leaving the compressor enters the condenser where it is

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cooled into low temperature. Then it is sucked by reciprocating compressor and is thus repeated.
Formula used:

Actual COP = refrigerant effect
I/p energy to compressor

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Refrigerant effect = mxCpx ? T
t
m - mass of water (kg)
Cp - Sp. Heat of water (4.2 kJ/kg K)
?T ? decrease in temp (Ti-Ts)

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t - timetaken duration of expt (sec)

Energy input =n x 3600 /k x t
n ? number of revolutions in energy meter
t ? time taken of ?n? revolutions

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k ? energy meter constant (3200)


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Tabulation:

Pressure of the refrigerant (Mpa) Temperature Time for n?
rev of
energy

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meter in
sec
P1 P2 P3 P4 Circulating fluid
temp
Refrigerant temp

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Ti Tf T1 T2 T3 T4

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72 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Model calculation:

Actual COP = refrigerant effect
I/p energy to compressor

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Refrigerant effect = mxCpx ? T
t
m - mass of water (kg)
Cp - Sp. Heat of water (4.2 kJ/kg K)
?T ? decrease in temp (Ti-Ts)

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t - time taken duration of experiment (sec)
Refrigerating effect = 8x4.2x (27-6)/1200=0.588 kw

Energy input = n x 3600
n ? Number of revolutions in energy meter

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t ? Time taken of ?n? revolutions
k ? Energy meter constant
=3 x 3600/(1200 x 54)
=0.166 kW
Actual COP = refrigerant effect

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I/p energy to compressor
= 0.588/0.166
=3.526
Result:

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The experiment was conducted successfully and coefficient of performance was found out is _______.

Outcome:
From this experiment, conducting the performance test on Vapour Compression Refrigeration
System and to determine the Coefficient of Performance using solenoid valve by throttling method is

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understood and this experiment could be used in the areas such as Refrigerator and Air Conditioning systems.
Applications:
Refrigerator, Air Conditioning.

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73 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the difference between air conditioning and refrigeration?
2. Write any three important properties of a good refrigerant.

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3. What is the function of analyzer and rectifier in an absorption system?
4. How does humidity affect human comfort?
5. What is the commonly used unit of refrigeration?
6. Distinguish between summer air conditioning and winter air conditioning.
7. Define ? RSHF Line

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8. Define ? By Pass Factor of a Heating Coil
9. What is the effect of sub cooling a refrigerant in a vapour compression cycle?
10. What is the function of analyzer and rectifier in an absorption system?
11. What is the purpose of generator assembly in vapour absorption refrigeration system?
12. State the substance used in the Lithium Bromide system and their functions.

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13. Differentiate wet compression from dry compression.
14. Define ? Apparatus Dew Point
15. What is meant by dew point temperature?
16. Define ? Wet Bulb Temperature
17. Define ? Degree of Saturation

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18. What is meant by specific humidity?
19. Define ? Relative Humidity
20. What is meant by dew point temperature?

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Viva ? voce

74 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.15

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PERFORMANCE TEST IN A FLUIDIZED BED
COOLING SYSTEM

Aim:

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To determine the performance test on cooling tower
Introduction:
The cooling tower is one of the most important device in chemical industries for example when the hot
water come from heat exchanger we use the cooling tower to cool it The purpose of cooling tower is to cool
relatively warm water by contacting with unsaturated air. The evaporation of water mainly provides cooling. In

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typical water cooling water tower warm water flows countercurrent to an airstream. Typically, the warm water
enters the top of the packed tower and cascades down through the packing , leaving at the bottom Air enters
at the bottom of the tower and flows upward through the descending water . The tower packing often consist of
slats of plastic or of packed bed. The water is distributed by troughs and overflows to cascade over slat
gratings or packing that provides large interfacial areas of contact between the water and air in the form of

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droplets and films of water. The flow of air upward through the tower can be induced by the buoyancy of the
warm air in the tower (natural draft) or by the action of a fan . The water cannot be cooled below the wet bulb
temperature. The driving force for the evaporation of water is approximately the vapour pressure of the water
less the vapour pressure it would have at the wet bulb temperature
Procedure:

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1. Introduce water and record its flow rate.
2. Switch ON the heaters on so that water is heated to the required temperature.
3. Introduce air and record its flow rate.
4. Wait for steady state then record steady state dry and wet bulb temperature of air at the entrance and
exit.

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5. Record the inlet and outlet temperature and flow rate of water also record temperature at different
stages.
Tabulation:

Sl.No. T1 (

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0
c) T2 (
0
c) T3 (
0

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c) Efficiency

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T1 = room temperature

75 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

T2 = water inlet

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T3 = water outlet

Efficiency of cooling tower

ECT = T3/T2/*100

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Model calculation:

Efficiency of cooling tower = water outlet
--------------- *100

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Water inlet

= 36/40 *100

= 90

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Result:
The performance test in cooling tower is determined as ______%.
Outcome:
From this experiment, conducting the performance test on cooling tower is understood and this
experiment could be used in various power plants where cooling tower is used.

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Applications:
Power Plant Cooling Tower, Cooling Tower.


1. What are functions of a draught system?

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2. What are the advantages of burning coal in pulverized form?
3. What are the functions of cooling tower?
4. What are the different types of draught system?
5. What are the methods used for handling of coal?
6. What is meant by fluidized bed combustion?

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7. What is the use of fluidized bed boiler?
8. What are the types of fluidized bed boiler?
9. State the purpose of condenser in fluidized bed boiler.
10. What is meant by pulveriser and why it is used?
11. State the disadvantages of pulverized coal firing.

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12. Distinguish between fouling and slagging.
Viva ? voce

76 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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ADDITIONAL EXPERIMENTS
BEYOND THE SYLLABUS

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77 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.16 AIR CONDITIONING TEST RIG

Aim:

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To conduct a performance test on air conditioning test rig and determine the Coefficient of Performance of
air conditioning system
Apparatus required:
(i) Thermometer
(ii) Electric Heater

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(iii) Stop watch
(iv) Digital anemometer
(v) Experimental setup
Description:
The test rig consist of

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1. An air duct support of stand
2. A blower to set up air flow through the duct along with a speed control to vary the
velocity of air.
3. A heater to rise the air temperature with regulator and energy meter.
4. Water spray, collecting tray, reservoir with gauge pump.

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5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.
(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after
cooling coil).
6. The test rig consists of compressor, condenser unit placed inside trolley and fitted
with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan

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for condenser and (iv) Liquid receiver.

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78 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

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Air conditioning Test Rig

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Sl.

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No

Inlet
temperat
ure

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Outlet
temperatu
re

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Pressu
re
P1

Tem

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p.
T1

Pressu
re

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P2
Temp.
T2

Pressu

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re
P3

Tem
p.

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T3


Pressu
re

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P4


Tem
p.

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T4

Energy for
10
revolutions

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Twet Tdry Twet Tdry Lb/in
o
C Lb/in
o
C Lb/in

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o
C
Lb/in
o
C

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Precautions:
1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence
avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kW only for the motor circuit.
2. Natural air currents in the room if in the direction of air duct may defect the experimental results and
hence the duct should be placed such that no wind from doors, windows, fan and cooling air from other

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test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan and
should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase beyond
240 psi.
3. Never exceed dry bulb temperatures of 40
0

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C after the heater (station 2) otherwise the air duct may be
damaged.
4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may
exceed its maximum of 32
0

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C and calibration may be affected.
5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not
running this will lead to rise in temperature at the heater and may damage the heater and the air duct.
6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their
duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.

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7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer is
placed inside the reservoir at the top. This may have to the cleaned when necessary.
8. Do not open the gate valve fully otherwise water may be splashed outside and the waster measurement
may be in error.
9. If the low pressure cut out comes in to action, it means that the Freon charge is insufficient and may have

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to be filled up. The suction pressure should never go below 2 psi as otherwise the compressor seals will
be damaged and air and moisture may enter the system.
10. The refrigerant strainer placed on the front panel should always be warm. If it cools and moisture
condenser on it, then the strainer might have to be charged by an experienced refrigeration mechanics.
11. The refrigerating system can work continuously for 2 hours, however if the room temperature is above

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25
0
C the condenser may be heated up and the delivery pressure may rise. Do not exceed 240 psi. Pour
one or two glasses of drinking water over the fins of the condenser in order to reduce the delivery
pressure.

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12. After some months of operation the compressor may have to be topped up with oil and some quantity of
Freon-22 may have to be charged by an experienced mechanics.

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80 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Formulae used:
1. Corresponding to the dry and wet bulb temperature at all the stations obtain the specific enthalpy and

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specific humidity values from psychometric chart.
i.e., h1 and w1 at tb1 and tw1 and so on.
2. Air flow rate, ma = (A x V) / v4 kg / sec
Where, A = Area of duct at outlet in m
2

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(0.46 m x 0.086 m)
V = Air velocity ( m / sec)
V4 = Specific volume of moist air at station 4 using psychometric chart m
3
/kg

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3. Heat added, Q1 = ma (h2 ? h1) kW
Where, h1 = Specific enthalpy at station 1 kJ/kg
h2 = Specific enthalpy at station 2 kJ/kg

4. Moisture added from psychrometric chart, mw1 = ma (w3-w2) Kg / sec.

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Where, w3 = Specific humidity at station 3
w2 = Specific humidity at station 2
5. Compressor power, W = (n / t) x (3600 / k) kW.
Where, n = No. of pulses of energy meter disc
t = Time taken for ?n? no. of pulses (sec)

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k = Energy meter constant (3200 lmp / kW-hr)
6. Actual C.O.P = Cooling effect produced on air / Compressor power.
7. Cooling effect produced on air, Qe = ma (h3 ? h4) kW.
Where, h3 = Specific enthalpy at state 3 kJ/kg
h4 = Specific enthalpy at state 4 kJ/kg

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8. Moisture condensed, mcl = ma (w3 ? w4) Kg/sec
Where, w3 = Specific humidity at station 3
w4 = Specific humidity at station 4
9. Draw the psychrometric process.

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Procedure:
1. Fill water in the wet bulb temperature probe trays.
2. Start the main.
3. Start the blower and run it the required speed by keeping the speed regulator at position.
4. Start the spray pump and open the gate valve suitably.

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5. Start the heater.

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6. Select the expansion device (Capillary tube / Thermostatic expansion valve)

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7. Start the cooling compressor.
8. Wait for some time till thermometers shown practically constant readings and note down the following
readings:
(ii) Dry bulb temperatures tdb1, tdb2, tdb3, tdb4.
(ii) Wet bulb temperatures twb1, twb2, twb3, twb4.

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(xi) Spray water temperature, ts
(xii) Surface temperature of cooler, tm ( at control panel)
(xiii) Pressure gauge reading, pd ( at control panel)
(xiv) Compound gauge reading, Ps ( at control panel)
(xv) Level reduction?l? in spray reservoir (mm) during 5 min.

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(xvi) Amount of condensate collected ?lc?, in a measuring jar at cooler tray during a
run of 5 minutes at constant conditions.
(xvii) Time in second ?SH? for 10 pulses of the energy meter disc connected to the
heater.
(xviii) Time in seconds Sc for 10 pulses of the energy meter disc connected to cooler

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1. Repeat the above procedures for four more different settings of the fan Regulator (Position 1,2,3,4 & 5). If
sensible cooling range is narrow, then switch off the spray and repeat as above. If the atmosphere is cool,
the heater may be set for greater dissipation. If more readings are required for cooling below dew point

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and dehumidification switch off heater and repeat procedure.
Result:
The Load test on the AIR CONDITIONING TEST RIG was conducted and the results are as follows.
1. Actual C.O.P of the system = ______________.
Outcome:

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From this experiment, conducting the performance test on air conditioning test rig and
determining the Coefficient of Performance of air conditioning system is understood and this experiment could
be used in the areas such as Refrigerator and Air Conditioning systems.
Applications:
Refrigerator, Air Conditioning.

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82 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by dew point temperature?
2. Define ? Effective Temperature

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3. Define ? COP of Refrigeration
4. Define ? Relative Humidity and Wet Bulb Temperature
5. Differentiate heat pump from refrigerator.
6. Define ? RSHF Line
7. Define ? By Pass Factor of a Heating Coil

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8. What is the effect of sub cooling a refrigerant in a vapour compression cycle?
9. What is the function of analyzer and rectifier in an absorption system?
10. What is the purpose of generator assembly in vapour absorption refrigeration system?
11. State the substance used in the Lithium Bromide system and their functions.
12. Differentiate wet compression from dry compression.

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13. Define ? Apparatus Dew Point
14. What is meant by dew point temperature?
15. Define ? Wet Bulb Temperature

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Viva ? voce
FirstRanker.com - FirstRanker's Choice
1 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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?



DEPARTMENT OF

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MECHANICAL ENGINEERING


ME6512 ? THERMAL ENGINEERING LABORATORY

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V SEMESTER - R 2013

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Name : _______________________________________

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Register No. : _______________________________________
Section : _______________________________________

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LABORATORY MANUAL
2 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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3 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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is committed to provide highly disciplined, conscientious and
enterprising professionals conforming to global standards through value based quality education and training.

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? To provide competent technical manpower capable of meeting requirements of the industry
? To contribute to the promotion of academic excellence in pursuit of technical education at different levels
? To train the students to sell his brawn and brain to the highest bidder but to never put a price tag on heart
and soul

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DEPARTMENT OF MECHANICAL ENGINEERING

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Rendering the services to the global needs of engineering industries by educating students to become
professionally sound mechanical engineers of excellent caliber

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To produce mechanical engineering technocrats with a perfect knowledge intellectual and hands on
experience and to inculcate the spirit of moral values and ethics to serve the society

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VISION
MISSION
VISION
MISSION

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PROGRAMME EDUCATIONAL OBJECTIVES (PEOs)

1. Fundamentals

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To impart students with fundamental knowledge in mathematics and basic sciences that will mould
them to be successful professionals
2. Core competence
To provide students with sound knowledge in engineering and experimental skills to identify complex
software problems in industry and to develop a practical solution for them

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3. Breadth
To provide relevant training and experience to bridge the gap between theory and practice which
enable them to find solutions for the real time problems in industry and organization and to design
products requiring interdisciplinary skills
4. Professional skills

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To bestow students with adequate training and provide opportunities to work as team that will build up
their communication skills, individual, leadership and supportive qualities and to enable them to adapt
and to work in ever changing technologies
5. Life-long learning
To develop the ability of students to establish themselves as professionals in mechanical engineering

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and to create awareness about the need for lifelong learning and pursuing advanced degrees

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PROGRAMME OUTCOMES (POs)

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On completion of the B.E. (Mechanical) degree, the graduate will be able
1. To apply the basic knowledge of mathematics, science and engineering
2. To design and conduct experiments as well as to analyze and interpret data and apply the same in the
career or entrepreneurship

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3. To design and develop innovative and creative software applications
4. To understand a complex real world problem and develop an efficient practical solution
5. To create, select and apply appropriate techniques, resources, modern engineering and IT tools
6. To understand the role as a professional and give the best to the society
7. To develop a system that will meet expected needs within realistic constraints such as economical

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environmental, social, political, ethical, safety and sustainability
8. To communicate effectively and make others understand exactly what they are trying to tell in both
verbal and written forms
9. To work in a team as a team member or a leader and make unique contributions and work with
coordination

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10. To engage in lifelong learning and exhibit their technical skills
11. To develop and manage projects in multidisciplinary environments

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6 Format No.: FirstRanker/Stud/LM/34/Issue: 00/Revision: 00

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ME6512 ? THERMAL ENGINEERING LABORATORY ? II

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? To study the heat transfer phenomena predict the relevant coefficient using implementation. To study the
performance of refrigeration cycle / components

LIST OF EXPERIMENTS:
HEAT TRANSFER LAB:

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1. Thermal conductivity measurement using guarded plate apparatus
2. Thermal conductivity measurement of pipe insulation using lagged pipe apparatus
3. Determination of heat transfer coefficient under natural convection from a vertical cylinder
4. Determination of heat transfer coefficient under forced convection from a tube
5. Determination of Thermal conductivity of composite wall

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6. Determination of Thermal conductivity of insulating powder
7. Heat transfer from pin-fin apparatus (natural & forced convection modes)
8. Determination of Stefan ? Boltzmann constant
9. Determination of emissivity of a grey surface
10. Effectiveness of Parallel / counter flow heat exchanger

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REFRIGERATION AND AIR CONDITIONING LAB:
11. Determination of COP of a refrigeration system
12. Experiments on Psychrometric processes
13. Performance test on a reciprocating air compressor

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14. Performance test in a HC Refrigeration System
15. Performance test in a fluidized Bed Cooling Tower

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1. Able to find out the thermal conductivity of various materials.
2. Able to determine the heat transfer through lagged pipe using lagged pipe apparatus
3. Able to find out the surface heat transfer coefficient of a vertical tube losing water by natural convection
experiment.
4. Able to conduct and find out the heat transfer coefficient by forced convection apparatus

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5. Able to find out the rate of heat transfer through different materials
6. Able to find out the thermal conductivity of insulating powder by conduction
7. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
8. Have attain the practical knowledge and able to find out the pin fin efficiency and net heat transfer rate.
9. Able to find out the Stefan Boltzman constant value.

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10. Able to find out the emissivity of the given test plate.
11. Able to conduct the load test on a refrigeration test rig and find out the volumetric efficiency and co-
efficient of performance for any type of refrigerant.
12. Have attain the practical knowledge on pscychrometric processes with air conditioning system
13. Able to find out the values of isothermal and volumetric efficiency by conducting the experiments at

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various delivery pressures
14. Able to conduct the experiment and find out the coefficient of performance.
15. Able to conduct the experiments and to find out the performance test in cooling tower of various FBC
Boiler.

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COURSE OBJECTIVES
COURSE OUTCOMES
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CONTENTS


Sl.No.

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Name of the experiment
Page No.
CYCLE 1 - EXPERIMENTS
1 Thermal conductivity measurement using guarded plate apparatus 6
2

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Thermal conductivity measurement of pipe insulation using lagged pipe
apparatus
11
3
Determination of heat transfer coefficient under natural convection from a

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vertical cylinder
15
4 Determination of heat transfer coefficient under forced convection from a tube 21
5
Determination of thermal conductivity of composite wall 27

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CYCLE 2 ? EXPERIMENTS
6
Determination of thermal conductivity of insulating powder 31
7
Heat transfer from pin-fin apparatus (natural & forced convection modes) 34

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8 Determination of stefan ? boltzmann constant 39
9 Determination of emissivity of a grey surface 43
10 Effectiveness of parallel / counter flow heat exchanger 47
CYCLE 3 ? EXPERIMENTS
11 Determination of cop of a refrigeration system 51

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12 Experiments on pscychrometric processes 58
13 Performance test on a reciprocating air compressor 63
14
Performance test in a HC refrigeration system 68
15 Performance test in a fluidized bed cooling system 72

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ADDITIONAL EXPERIMENTS BEYOND THE SYLLABUS
16 Air conditioning test rig 75
PROJECT WORK 81

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Expt. No.1

THERMAL CONDUCTIVITY MEASUREMENT
USING GUARDED PLATE APPARATUS

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Aim:
To conduct an experiment to find the thermal conductivity of a given plate using two slab guarded hot plate
method
Apparatus required:

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(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:

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The heater plate is surrounded by a heating ring for stabilizing the temperature of the primary heater and to
prevent heat jobs radially around its edges. The primary and guard heater are made up of mica sheets in
which is a wound closely spaced Nichrome wire and packed with upper and lower mica sheets. These heaters
together form a flat which together with upper and lower copper plates and rings form the heater plate
assembly.

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Two thermocouples are used to measure the hot face temperature at the upper and lower central heater
assembly copper plates. Two more thermocouples are used to check balance in both the heater inputs.
Specimens are held between the heater and cooling unit on each side of the apparatus. Thermocouples
No.5 and No. 6 measure the temperature of the upper cooling plate and lower cooling plate respectively.The
heater plate assembly together with cooling plates and specimen held in position by 3 vertical studs and nuts

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on a base plate are shown in the assembly drawing.The cooling chamber is a composite assembly of grooved
aluminum casting and aluminum cover with entry and exit adaptors for water inlet and outlet.

Formulae used:
1. Power input, Q = V ? A / 2 W

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2. Thermal Conductivity, K = (Q ? dx)/(A x dt) W/mK
3. Area, A = ( ?/4) d
2
(10 + x)

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cm
2

4. Average Temperature, dT = (T1+T2+T3+T4)/4 ? (T5+T6)/2
Precautions:

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1. Keep dimmer stat to zero volt position before start.
2. Increase the voltage gradually.

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3. Start the cooling circuit before switching ON the heaters and adjust the flow rate so that practically there
is no temperature rise in the circuiting fluid.
4. Keep the heater plate undisturbed and adjust the cooling plates after keeping the samples with the help
of nuts gently
5. Keep the loosely filled insulation (Glass wool) packets gently and remove them slowly so that they do

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not disturb the thermocouples terminals and heater wires.

Specifications:
1. Diameter of the heating plate = 100 mm
2. Width of the heating ring = 37 mm

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3. Inside diameter of the heating ring = 106 mm
4. Outside diameter of the heating ring = 180 mm
5. Maximum thickness of the specimen = 25 mm
6. Minimum thickness of the specimen = 6 mm
7. Diameter of the specimen = 140 mm

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8. Mean temperature range = 40
0
C ? 100
0
C

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9. Maximum temperature of the hot plate = 170
0
C
10. Diameter of the cooling plates = 180 mm
11. Central Heater: Nichrome strip type sandwiched between mica sheets (400 W)

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12. Guarded Heater Ring: Nichrome strip type sandwiched between mica sheets (400 W)
13. Dimmer stat 2 Nos. = (0 ? 2 A) ? 240 V
14. Voltmeter = 0 ? 100 / 200 V
15. Ammeter = 0 ? 2 A
16. Thermocouples = 6 Nos. (Chromel Alumel)

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17. Insulation Box = 375 mm x 375 mm (Approx)
18. Temperature indicator = 0 ? 200
0
C
19. Width of gap between two heater plates (x) = 2.5 mm

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20. Specimen thickness (L) = 12.5 mm
21. Specimen used = Press wood

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Tabulation:
Sl. No. Voltmeter
V
Ammeter
A

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Main heater (
0
C) Test Plate (
0
C)

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T1 T2 T3 T4 T5 T6



Schematic view of the test set-up:

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Procedure:
1. Place the specimens on either side of the heating plate assembly, uniformly touching the cooling plates.
Fill the outer container with loose fill insulation such as glass wool.

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2. Open the cooling water valve before switching ON the apparatus, and ensure that enough cooling water
is passed through the cooling plates.
3. Switch ON the apparatus and heat input to the central and guarded heaters through separate single
phase supply lines with dimmer stat.
4. Provide correct heat input to the central and guarded plates for adjusting the dimmer stat switch.

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5. Adjust the guarded heater input in such a way that there is no radial heat flow which is checked from
thermocouple readings and is adjusted accordingly.

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6. Observe and record the current, voltage and thermocouples readings every 10 minutes till a reasonably
steady state condition achieved.
7. Write the readings in the observation table.
8. Take the final steady state values for calculations.

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Result:
Thus the experiment was done and thermal conductivity of given material was found to be
k = ___________________ W /mK.

Outcome:

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From this experiment, finding the thermal conductivity of a given plate using two slab guarded
hot plate method is learnt and this experiment could be used in the areas such as Pipe lines, IC engines, heat
exchangers, etc. where thermal conductivity is to be found.

Applications:

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Pipe lines, IC engines, heat exchangers

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1. Define ? Thermal Conductivity
2. State Fourier?s law of heat conduction.
3. State the applications of fins.
4. Define ? Fins

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5. State Newton?s law of cooling or convection law.
6. What are the factors affecting the thermal conductivity?
7. What is the value of thermal conductivity for wood?
8. What are the various modes of heat transfer?
9. What is meant by conduction?

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10. Define ? Heat Transfer
11. State the purpose of heating ring provided in this experiment.
12. What is meant by transient heat conduction?
13. How heat transfer occurs through insulated medium?
14. What are the material used for making the guarded plate?

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15. How many thermocouples were mounted in this experiment?
16. Specify the thermocouple numbers which was used to measure the cooling plate temperature.
17. What is unit for thermal conductivity?
18. What is meant by Newtonian and Non-Newtonian fluids?
19. What is meant by dimensional analysis?

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20. State the advantages of dimensional analysis.

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Viva ? voce

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Expt. No.2

THERMAL CONDUCTIVITY MEASUREMENT OF
PIPE INSULATION USING LAGGED PIPE

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APPARATUS

Aim:
To determine the heat transfer through lagged pipe using lagged pipe apparatus
Apparatus required:

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(i) Experimental setup
(ii) Lagged pipe apparatus
(iii) Thermocouple
(iv) Ammeter
(v) Voltmeter

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Theory:
The insulation is defined as a material which retards the heat flow with reasonable effectiveness. Heat is
transferred through insulation by conduction, convection and radiation or by the combination of these three.
There is no insulation which is 100 % effective to prevent the flow of heat under temperature gradient.

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The experimental set-up in which the heat is transferred through insulation by conduction is understudy in
the given apparatus. The apparatus consisting of a rod heater with asbestos lagging. The assembly is inside
an MS pipe. Between the asbestos lagging and MS pipe, saw dust is filled.

Specifications:

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1. Diameter of the heater Rod = 20 mm.
2. Diameter of the heater Rod with Asbestos lagging = 40 mm
3. The diameter of the heater Rod with Asbestos and Saw dust lagging, ie.
4. The ID of the outer MS pipe = 80 mm
5. The effective length of the above = 500 mm

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Precautions:
1. Adjust the temperature indicator to ambient level by using compensation screw, before starting the

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experiment (if needed).
2. Keep dimmer stat to zero volt position and increase it slowly.
3. Use the proper range of Ammeter and Voltmeter.
4. Never exceed 80W
Formulae used:

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The heat flow through the lagging materials is given by
Q = k1 2?L?T/ln(r2/r1) (OR) k2 2?L?T/ln(r3/r2)
Where, ?T = Temperature drop across lagging
k1 = Thermal conductivity of Asbestos lagging material
k2 = Thermal conductivity of Saw dust.

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L = Length of the cylinder, knowing the thermal conductivity of one lagging
material the thermal conductivity of the other insulating material can be found
Tabulation:
Sl.
No.

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Voltage
(V)
Current
(A)
Heater Temperature

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(
0
C)
Asbestos Temperature
(

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0
C)
Saw dust
Temperature (
0

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C)
T1 T2 T3 Average T4 T5 T6 Average T7 T8 Average

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Procedure:
1. Switch ON the units and check if all channels of temperature indicator showing proper temperature.
2. Switch ON the heater using the regulator and keep the power input at some particular value.

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3. Allow the unit to stabilize for about 20 to 30 minutes.
4. Now note down the Ammeter, Voltmeter reading which gives the heat input.
5. Note the temperatures T1, T2 and T3 on the heater rod; T4, T5 and T6 temperatures on the asbestos
layer and T7 and T8 temperatures on the saw dust lagging.
6. Take the average temperature of each cylinder for calculation. Measure the temperatures by

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thermocouples (Fe/Ko) with multipoint digital temperature indicator.
7. Repeat the experiment for different heat inputs.
Results:
The heat transfer through lagging material = ____________________ W.
The thermal conductivity of resistive material = _________________ W /m

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2
-K

Outcome:
From this experiment, finding the heat transfer through lagged pipe using lagged pipe

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apparatus is understood and this experiment could be used in the areas such as Exhaust pipe lines, IC
engines, heat exchangers, etc. where heat transfer is to be found.

Applications:
Exhaust pipe lines, IC engines, heat exchangers

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1. Define ? Nusselt Number(Nu)
2. What is meant by laminar flow and turbulent flow?

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3. What is meant by free or natural convection?
4. What is meant by forced convection?
5. Define ? Reynolds Number(Re)
6. Define ? Prandtl Number(Pr)
7. Define ? Convection

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8. What is meant by transient heat conduction?
9. What is meant by thermal boundary layer?
10. How does the heat transfer occur through insulated medium?
11. What is the material of the pipe?
12. Where was the saw dust filled in this experimental set up?

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13. What is meant by steady state heat conduction?
14. Define ? Periodic Heat Flow
15. List out the examples for periodic heat flow.
16. What is meant by thermal diffusion?
17. What are the dimensionless parameters used in forced convection?

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18. Define - Dimensional Analysis
19. State the demerits of dimensional analysis.
20. What is meant by hydrodynamic boundary layer?

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Viva ? voce

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Expt. No.3

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER NATURAL CONVECTION
FROM A VERTICAL CYCLINDER

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Aim:
To conduct an experiment on heat transfer and to find the surface heat transfer co-efficient for a vertical
tube losing heat by natural convection
Apparatus required:

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(i) Experimental setup
(ii) Thermocouple
(iii) Ammeter
(iv) Voltmeter
Theory:

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The apparatus consists of a brass tube fitted in a rectangular duct in a vertical fashion. The duct is open at
the top and bottom, and forms an enclosure and serves the purpose of undisturbed surroundings. One side of
the duct is made up of Perspex for visualization. An electric heating element is kept in the vertical tube which
in turn heats the tube surface. The heat is lost from the tube to the surrounding air by natural convection. The
temperature of the vertical tube is measured by seven thermocouples. The heat input to the heater is

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measured by an Ammeter and a Voltmeter and is varied by a dimmer stat.

When a hot body is kept in a still atmosphere, heat is transferred to surrounding fluid by natural convection.
The fluid layer in contact with the hot body gets heated, rises up due to the decrease in its density and the cold
fluid rushes in from bottom side. The process is continuous and the heat transfer takes place due to the

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relative motion of hot and cold fluid particles.

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Schematic view of the test set-up:
mm
mm

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Specifications:
1. Diameter of the tube(d) = 40 mm

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2. Length of the tube (L) = 500 mm
3. Duct size = 200 mm x 200 mm x 750 mm
4. No. of thermocouples = 7 and are shown as 1 to 7 and as marked on Temperature indicator switch
Thermocouple No. 6 reads the temperature of air in the duct.
5. Temperature Indicator = 0 ? 300

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0
C. Multichannel type, calibrated for chromel ? alumel
thermocouples
6. Ammeter = 0 ? 2 A
7. Voltmeter = 0 ? 100 / 200 V

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8. Dimmerstat = 2 A / 230 V
9. Heater = Cartridge type (400 W)

Tabulation:
Sl. No.

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Voltage Current Temperature of Thermocouple (
0
c)

V A

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T1 T2 T3 T4 T5 T6

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Formulae used:
1. Heat transfer coefficient is given by
h = q / {As (Ts ? Ta)}
Where, h = average surface heat transfer coefficient W/m
2

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K
As = Area of heat transfer surface = ? x d x l m
2

Ts = Average of surface Temperature = (T1 + T2 + T3 + T4 + T5 + T6 + T7) / 7

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0
C
q = heat transfer rate W
Ta = T8 Ambient temperature in duct (
0

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C) ?
2. hL / k = A { g L
3
?T Cp ?/2v
2

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}
n

Where, hL / k are called Nusselt Number.
L

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3
g?T / v
2
is called Grashof number.
?Cp / k called Prandtl Number.

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A and n are constants depending on the shape and orientation of the heat transferring surface.
Where, L = A characteristic dimension of the surface
K = Thermal conductivity of fluid
v = Kinematics viscosity of fluid
? = Dynamic viscosity of fluid

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Cp = Specific heat of fluid
? = Coefficient of volumetric expansion of the fluid
G = Acceleration due to gravity
?T = Ts ? Ta
For gas, ?= 1/ (Tf + 273)

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0
K
-1

Where Tf = (Ts + Ta )/ 2

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For a vertical cylinder losing heat by natural convection, the constant A and n of equation have been
determined and the following empirical correlation obtained.
hL / k = 0.56 (Gr.Pr)
0.25

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for 10
4
< Gr.Pr.<10
8

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hL / k = 0.13 (Gr.Pr)
1/3
for 10
8
< Gr.Pr.<10

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12
Here, L = Length of the cylinder

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Procedure:
1. Switch ON the supply and adjust the dimmer stat to obtain the required heat input.
2. Wait till a fairly steady state is reached, which is confirmed from temperature readings (T1 to T7).
3. Note down surface temperatures at the various points.
4. Note the ambient temperature (T8).

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5. Repeat the experiment at different heat inputs.

Results:
The surface heat transfer coefficient of a vertical tube losing water by natural convection is found as
Theoretical = ______________ W/ m

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2
K
Experimental = ______________ W/ m
2
K

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Outcomes:
From this experiment, finding the surface heat transfer coefficient of a vertical tube losing
heat by natural convection experiment is studied and this experiment could be used in the areas such as IC
engines, heat exchangers, Steam boilers, Pressure Cookers, etc. where heat transfer co. efficient is to be

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found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker.

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1. Define ? Grash of Number(Gr)

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2. What is meant by Newtonian and Non ? Newtonian fluids?
3. Define ? Boundary Layer Thickness.
4. What is the form of equation used to calculate heat transfer for flow through cylindrical pipes?
5. What is meant by dimensional analysis?
6. Define ? Momentum Thickness

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7. What are the advantages of dimensional analysis?
8. State the limitations of dimensional analysis.
9. Define ?Stanton Number(St)
10. What are the types of boundary layer available in heat transfer?
11. What is meant by thermal boundary layer?

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12. Define ? Hydrodynamic Boundary Layer
13. What is meant by free convection?
14. Define ? Energy Thickness
15. Differentiate free from forced convection.
16. Explain the significance of boundary layer in heat transfer.

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17. Write the expression for Newton's law of cooling.
18. Define ? Displacement Thickness
19. What is meant by critical radius of insulation?
20. Define ? Overall Heat Transfer Coefficient

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Viva ? voce

23 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No. 4

DETERMINATION OF HEAT TRANSFER
COEFFICIENT UNDER FORCED CONVECTION

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FROM A TUBE

Aim:
To determine the heat transfer co-efficient by using forced convection apparatus

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Apparatus required:
(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer

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Theory:
Apparatus consist of blower unit fitted with the test pipe. The test section is surrounded by Nichrome band
heater. Four thermocouples are embedded on the test section and two thermocouples are placed in the air
stream at the entrance and exit of the test section to measure the air temperature. Test pipe is connected to
the delivery side of the blower along with the orifice to measure flow of air through the pipe. Input to the heater

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is given through a dimmer stat and measured by meters. It is to be noted that only a part of the total heat
supplied is utilized in heating the air. A temperature indicator with cold junction compensation is provided to
measure temperatures of pipe wall at various points in the test section. Air flow is measured with the help of
orifice meter and the water manometer fitted on the board.

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24 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Tabulations:

Sl. No. Voltage Current Temperature in (
0
C)

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Manometer
reading of water
in h in meter

(V) (A)

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T1

T2

T3

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T4

T5

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T6

h1
cm
h2

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cm

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25 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Specifications:
1. Pipe diameter outside (Do) = 40 mm

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2. Pipe diameter inner (Di) = 28 mm
3. Length of test section (L) = 500 mm
4. Blower = 0.28 HP motor
5. Orifice diameter (d) = 20 mm, connected with to water manometer
6. Dimmer stat = 0 to 2 A, 260 V, A.C

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7. Temperature Indicator = Range 0 to 300
0
C
(Calibrated for chromel alumel thermocouple)
8. Voltmeter = 0 -100/200 V

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9. Ammeter = 0-2 A
10. Heater = Nichrome wire heater wound on test pipe (Band type) (400 W)
Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.

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3. Increase the voltmeter gradually.
4. Do not stop the blower in between the testing period.
5. Do not disturb thermocouples while testing.
6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W

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Procedure:
1. Start the blower and adjust the flow by means or gate valve to some desired difference
in manometer level.
2. Start the heating of the test section with the help of dimmer stat and adjust desired heat
input with the help of voltmeter and ammeter.

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3. Take readings of all the six thermocouples at an interval of 10 minutes until the steady
state is reached.
4. Note down the heater input.

26 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. The rate at which air is getting heated is calculated as
qa = m x Cp x ?T ( kJ / hr)
Where, m = mass flow rate of air (Kg / hr)

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Cp = Specific heat of air (kJ/ kg /K)
?T = Temperature rise in air (
o
C)
= T6 ? T1.

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2. m = Q?
Where, ? = density of air to be evaluated at (T1 + T6)./ 2 Kg / hr
Q = Volume flow rate
Q = Cd x (?/4) di
2

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?2gH x (?w / ?a) m
3
/hr
3. ha = qa /A(Ts- Ta) W / m
2

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K
qa = Rate of which air is getting heated.
A = Test section area = ? x Di x L m
2

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Ta = Average temperature of air = (T1 + T6)/2
o
C
Ts = Average surface temperature = (T2 + T3 + T4 + T5)/4
o

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C
Cd = 0.64
H = Difference of water level in manometer m
?w Density of water = 1000 Kg/m
3

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?a = Density of air = [101.3/(0.287*Ta)] Kg/m
3

d = diameter of orifice meter = 0.014 m

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g = acceleration due to gravity = 9.81 m/s
2

using this procedure obtain the value of ?ha? for different air flow rate
4. Reynold?s Number:

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Re = VDi/ v Dimensionless number
Where, V = velocity of air = Q/[(? x Di
2
)/4]
v = Kinematics viscosity to be evaluated at bulk mean temperature

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(T1 + T6)/2
o
C
5. Nusselt Number:
Nu = (ha x Di)/ k Dimensionless number

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K = Thermal conductivity of air at (T1 + T6)/6 W/m-K
Plot the values of Nu Vs Re on a log ? log plot for the experiment readings
6. Prandtl Number:

27 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Pr = Cp? / k
Cp = Specific heat of fluid kJ/kg.k
? = Viscosity Ns/m
2

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k = Thermal conductivity of fluid W/m
2
K
Nu = 0.023 (Re)

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0.8
(Pr)
0.4
Bulk mean temperature = (T1 + T6)/2

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Results:
Thus the heat transfer coefficient in forced convection was determined by using forced convection
apparatus.
hactual = -------------- W/m
2

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K
htheoritical = -------------- W/m
2
K

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Outcome:
From this experiment, determining the heat transfer co-efficient by using forced convection
apparatus is understood and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where heat transfer co. efficient is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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28 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by boiling and condensation?
2. What is meant by pool boiling?
3. What is the scope of this experiment?
4. List the apparatus required to conduct this experiment.

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5. State the purpose of blower fitted in this test set-up.
6. How many thermocouples were located in this experimental set-up?
7. What is the need of orifice provided in this set-up?
8. What is meant by LMTD?
9. Write about the applications of boiling and condensation.

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10. How is the air flow measured in this experiment?
11. What are the various types of heat exchangers?
12. Define ? Forced Convection
13. Distinguish between forced and free convection.
14. What are the dimensional parameters used in forced convection?

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15. Define ? Momentum Thickness

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Viva ? voce

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29 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.5 HEAT TRANSFER THROUGH COMPOSITE WALLS

Aim:

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To conduct and determine the rate of heat transfer through different layers of composite wall
Description of apparatus:
When heat conduction takes place through two or more solid materials of different thermal conductivities,
the temperature drop across each material depends on the resistance offered to heat conduction and the
thermal conductivity of each material. The experimental set-up consists of test specimen made of different

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materials aligned together on both sides of the heater unit. The first test disc is next to a controlled heater. The
temperatures at the interface between the heater and the disc is measured by a thermocouple, similarly
temperatures at the interface between discs are measured. Similar arrangement is made to measure
temperatures on the other side of the heater. The whole set-up is kept in a convection free environment. The
temperature is measured using thermocouples (Iron-Cons) with multi point digital temperature indicator. A

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channel frame with a screw rod arrangement is provided for proper alignment of the plates. The apparatus
uses a known insulating material, of large area of heat transfer to enable unidirectional heat flow. The
apparatus is used mainly to study the resistance offered by different slab materials and to establish the heat
flow is similar to that of current flow in an electrical circuit. The steady state heat flow Q = ?t/R Where, ?t = is
the overall temperature drop and R is the overall resistance to heat conduction. Since the resistance are in

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series R = R1 + R2 Where R1, R2 are resistance of each of the discs.
Specification:
1. Thermal conductivity Of sheet asbestos = 0.116 W/mK : Thickness = 6mm
2. Thermal conductivity of wood = 0.052 W/mK Thickness = 10mm
3. Dia. of plates = 300mm

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4. The temperatures are measured from bottom to top plate T1, T2,?.T8.
Procedure:
1. Turn the screw rod handle clockwise to tighten the plates.
2. Switch on the unit and turn the regulator clockwise to provide any desired heat
input.

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3. Note the ammeter and voltmeter readings.
4. Wait till steady state temperature is reached.
5. (The steady state condition is defined as the temperature gradient across the

30 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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plates that does not change with time.)
6. When steady state is reached note temperatures and find the temperature
gradient across each slab.
7. Since heat flows from the bottom to top of the heater, the heat input is taken as

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Q/2 and the average temperature gradient between top and bottom slabs from
the heater is to be taken for calculations. Different readings are tabulated as follows.
Calculation:
Now the resistance (R ) offered by individual plates for heat flow
R1 = L1/AK1 R2 = L2 / AK2 R3 = L3/AK3

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Where, A=Area of the plate K=Thermal Conductivity L=Thickness of the plate
Knowing the thermal conductivities
Q = (T4?T1)/R = (T2?T1)/R1 = (T3?T2)/R2 = (T4?T3)/R
Tabulation:
Sl.No. Voltmeter

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reading
(V)
Ammeter
reading
(A)

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T1
(
0
C)
T2

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(
0
C)
T3
(

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0
C)
T4
(
0

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C)
T5
(
0
C)

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T6
(
0
C)
T7

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(
0
C)
T8
(

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0
C)

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31 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Composite wall apparatus set-up

Result:

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The rate of heat transfer through different materials are found to be
a. MS section = ------------------W
b. Wood section = ---------------W
c. Asbestos section = ------------W

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Outcome:
From this experiment, determining the rate of heat transfer through different materials is learnt
and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers, Pressure
Cookers, Fins, Motor bodies, etc. where rate of heat transfer is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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32 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. Define ? Heat Transfer

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2. How does heat transfer occur through composite walls?
3. Write about the merits of drop wise condensation.
4. What is meant by film wise and drop wise condensation?
5. What happens when heat conduction takes place through two or more solids of different thermal
conductivities?

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6. Give the expression for heat transfer through a composite pipes or cylinder.
7. State Newton's law of cooling.
8. Explain the significance of Fourier number.
9. What is meant by effectiveness?
10. Define ? Heat Exchanger

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11. What is meant by fouling factor?
12. Give the expression for heat transfer through a composite plane wall.

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Viva ? voce

33 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.6

DETERMINATION OF THERMAL CONDUCTIVITY
OF INSULATING POWDER

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Aim:
To find out the thermal conductivity of insulating powder by conduction
Apparatus required:

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The apparatus consists of concentric spheres made of copper. The inner sphere is a heater, and in between
the spheres insulating powder (magnesium oxide) is filled and sealed. There are two thermo couples, T1 and
T2, fixed to the heater, and two thermocouples, T3 and T4, fixed on the inner wall of the outer sphere. A
multiunit digital temperature indicator is provided to measure temperature at different locations. The whole unit
is mounted on a laminated work bench with panel. An ammeter - voltmeter is provided to measure the input

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power and dimmer stat is provided to vary the input power.

Procedure:

1. Switch on the unit and adjust the input power to the required extent.

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2. Allow the temperature to stabilize.
3. Note the ammeter and voltmeter readings.
4. Note the temperature at different locations from T1 to T4.
5. Repeat the experiments for different power inputs.

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The readings are tabulated below

Sl.No. Voltmeter
reading( V)

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Ammeter
reading (A)
T1
(
0

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C)
T2
(
0
C)

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T3
(
0
C)
T4

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(
0
C)

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Calculations:
The radius of the inner sphere (r1) - 38 mm
The radius of the outer sphere (r2) - 75mm
The power input Q =V x A=4?(t1-t2)kr2-r1/r2-r1
Where K is the thermal conductivity of the insulating powder t1 and t2 are the average temperature of the

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inner sphere, and the outer sphere respectively.


34 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Fig. 1 Apparatus of thermal conductivity of insulating powder

[1. Shell, 2.Voltmeter, 3.Ammeter, 4.Temperature indicator, 5.Selector switch, 6.Main switch & 7.Heater
control]

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Result:
The thermal conductivity of insulating powder by conduction is found and the result is, ___________

Outcome:

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From this experiment, evaluating the thermal conductivity of insulating powder by conduction is
analyzed and this experiment could be used in the areas such as IC engines, heat exchangers, Steam
boilers, Pressure Cookers, Fins, Motor bodies, etc. where the thermal conductivity of insulating material is to
be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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35 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the need for conducting this experiment?
2. Define - Thermal Conductivity
3. What is the unit for thermal conductivity?
4. What is meant by mass transfer?

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5. What are the factors which affect the thermal conductivity?
6. Write the examples of mass transfer.
7. Mention the insulating powder used in this experiment.
8. What are the different modes of mass transfer?
9. How many thermocouples were mounted in this test rig?

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10. What is meant by molecular diffusion?
11. What is meant by Eddy diffusion?
12. What was the material selected for constructing sphere?
13. Define ? Reynolds Number(Re)
14. Define ? Prandtl Number(Pr)

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15. Define ? Convection
16. What is meant by transient heat conduction?
17. What is meant by thermal boundary layer?
18. How heat transfer occurs through insulated medium?
19. In which location the saw dust were filled in this experimental set up?

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20. What is meant by steady state heat conduction?

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Viva ? voce

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36 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.7

HEAT TRANSFER FROM PIN-FIN APPARATUS

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(NATURAL AND FORCED CONVECTION MODES)

Aim:
To determine the pin-fin efficiency and heat flow through pin-fin by forced convection.
Apparatus required:

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(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:
A brass fin of circular cross section is fitted across a long rectangular duct. The other end of the duct is

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connected to the suction side of a blower and the air blows past the fin perpendicular to its axis. One end of
the fin projects outside the duct and is heated by a heater. Temperatures at five points along the length of the
fin are measured by chrome alumel thermocouples connected along the length of the fin. The air flow rate is
measured by an orifice meter fitted on the delivery side of the blower. Schematic diagram of the set up is
shown in fig. while the details of the fin are shown.

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Tabulations:
Forced convection:
Sl.
No.
V I

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Fin Temperatures (
0
C)
Ambient Temp

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(
0
C)
Manometer
Reading

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(V)

(A)

T1 T2 T3 T4 T5 T6 T7 T8

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h1
cm
h2
cm

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37 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Specifications:
1. Duct size = 150 mm x 100 mm.
2. Diameter of the fin = 12 mm
3. Effective length of fin = 14.5 cm

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4. Diameter of the orifice = 24 mm
5. Diameter of the delivery pipe (O.D) = 46 mm

Schematic view of the test set-up:

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zzzzzzzzzzzzzzzz

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6. Diameter of the delivery pipe (I.D) = 42 mm

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7. Coefficient of the discharge (cd) = 0.64
8. Centrifugal blower = 0.56 HP, single phase motor
9. No. of thermocouples on fin = 5
10. Thermocouple (6) reads ambient temperature inside of the duct.
11. Thermal conductivity of fin material (Brass) =110 W/m.

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0
C
12. Temperature indicator = 0 ? 300
0
C

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(With compensation of ambient temperature up-to 50
0
C)
13. Dimmer stat for heat input controls 230 V, 2 A
14. Heater suitable for mounting at the fin end outside the duct = 400 watts (Band type)

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15. Voltmeter = 0 ? 100 / 200 V
T7 T6 T5 T4 T3 T2 T1
T8
Brass Pin Fin
Heater

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38 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

16. Ammeter = 0 ? 2 A
Precautions:

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1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Start the blower unit.
3. Increase the voltmeter gradually.
4. Do not stop the blower during the testing period.
5. Do not disturb thermocouples while testing.

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6. Operate selector switch of temperature indicator gently.
7. Do not exceed 200 W.
Procedure:
Forced Convection:
1. Start heating the fin by switching ON the heater element and adjust the voltage on dimmer stat to, say,

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100 volts.
2. Start the blower and adjust the difference of level in the manometer with the help of gate valve.
3. Note down the thermocouple readings 1 to 5 at a time interval of 5 minutes.
4. When steady state is reached, record the final readings 1 to 5 and also record the ambient
temperature reading 6.

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5. Repeat the same experiment with different manometer readings.
Formulae Used :( Forced Convection)
1. Film Temperature Tf = ( T? + Tw) / 2
Where, T? = surface temperature (T6)
Tw = (T1 + T2 + T3 + T4 + T5) / 5 (average temperature of fin)

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2. Discharge of air Q = Cd x {(? x D
2
) /4}?2gha m
3
/s.

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Where, ha (head of air) = (?w / ?a) x H m
H = Difference of water level in manometer m
?w Density of water = 1000 kg/m
3

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?a = Density of air = 1.165 kg/m
3
g = acceleration due to gravity = 9.81 m/s
2

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Cd = Coefficient of discharge = 0.64
D = diameter of the orifice
3. Velocity of air, V = Q/A m/s
Where Q = discharge of air

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39 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

A = area of the duct
4. Reynold?s Number:
Re = Vmf D/ v Dimensionless number

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Where, Vmf = velocity of air at mean film temp. = VTf/ T?
D = diameter of the fin
v = Kinematics viscosity to be evaluate at average of bulk mean temperature.
(T1 + T6) / 2
o

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C
5. Heat transfer coefficient, h = Nu k / D
Where Nu = Nusselt Number
6. Nusselt Number:
Nu = CRe

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m
(Pr)
0.33
7. Heat flow, Q = ?hpkA x (Tw ? T?) tan h (mL)
h = heat transfer coefficient,

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Where, p = perimeter in m
k= 386 w/mk
m= ?(hp/kA)
A = area of fin = (? x D
2

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) /4
L = Length of the fin
Tw ? average temperature
T? ? ambient (surface) temperature (T6)
8. Efficiency, ? = {tan h (mL)}/ mL

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Results:
Thus the experiment was conducted and results found were
Pin fin Efficiency, ? = ___________
Heat transfer, Q = ___________ W

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Outcome:
From this experiment, determining the pin-fin efficiency and heat flow through pin-fin by forced
convection is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the pin-fin efficiency and heat flow through
pin-fin is to be found.

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40 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.


1. Define ? Extended Surface
2. What is meant by convective mass transfer?

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3. State the applications of fins.
4. What is meant by free convective mass transfer?
5. Define ? Heat Transfer
6. Define ? Fin Efficiency
7. What are the various modes of heat transfer?

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8. Define ? Conduction
9. What is meant by fin effectiveness?
10. What is meant by steady state heat conduction?
11. Define ? Convection
12. What is meant by transient heat conduction?

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13. What is meant by radiation?
14. Define ? Reynold's Number
15. Give the expression for calculating velocity of air.

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Viva ? voce

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41 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.8

DETERMINATION OF STEFAN ? BOLTZMANN

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CONSTANT

Aim:
To determine the Stefan Boltzman Constant by using boltzman apparatus
Apparatus required:

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(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Geyser water
Theory:

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The apparatus is centered on flanged copper hemisphere B fixed on a flat non-conducting plate A. The
outer surface of B is enclosed in a metal water jacket used to heat B to some suitable constant temperature.
The hemispherical shape of B is chosen solely on the grounds that it simplifies the task of draining water
between B & C. Four chromel alumel thermocouples are attached to various points on surface of B to
measure its mean temperature. The disc D, which is mounted in an insulating bakelite sleeve S is fitted in a

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hole drilled in the centre of base plate A. The base of S is conveniently supported from under side of A. A
chromel alumel thermocouple is used to measure the temperature of D (T5). The thermocouple is mounted on
the disc to study the rise of its temperature.
When the disc is inserted at the temperature T5 (T5 > T i.e the temperature of the enclosure), the response
of temperature change of disc with time is used to calculate the Stefan Boltzman constant.

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Specifications:
1. Hemispherical enclosure diameter = 200 mm
2. Suitable sized water jacket for hemisphere
3. Base plate, bakelite diameter = 240 mm
4. Sleeve size, diameter = 44 mm

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5. Fixing arrangement for sleeve
6. Test disc, diameter = 20 mm
7. Mass of test disc = 0.008 kg
8. Specific heat, s of the test disc = 0.41868 kJ / Kg
0

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C
= (or) 0.1 Kcal / kg
0
C
9. No. of thermocouples mounted on B = 4 Nos.

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10. No. of thermocouples mounted on D = 1 No.

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11. Temperature indicator digital 0.1

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0
C L.C 0 - 200
0
C with built-in cold junction compensation and a timer set
for 5 sec. to display temperature rise of the disc.

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12. Immersion water heater of suitable capacity = 1.4 kW
13. Tank for hot water
Precautions:
Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.

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Formulae Used:
Stefan Boltzman constant = ? = {m x Cp ( dT / dt)t = 0} / A ( Th
4
? Td
4

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)
Where, A = area of the disc
Th = Emitter temperature (average of T1, T2, T3)
Td = Absorber temperature = T0
dT / dt find the slope from the graph, Temperature T in Y axis, and time t in X axis.

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Schematic view of the test set-up:

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Heater

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Tabulations:
Proc
edur
e:
1. H

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eat the
water
in the
tank by
the immersion heater up to a temperature of about 90

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0
C.
2. Remove the disc, D before pouring the hot water in the jacket.
3. Pour the hot water in the water jacket.
4. Let the hemispherical enclosure B and A come to some uniform temperature T in short time after filling

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the hot water in the jacket. The thermal inertia of hot water is quite adequate to present significant
cooling in the time required to conduct the experiment.
5. Let the enclosure come to thermal equilibrium conditions.
6. Insert the disc D now in A at a time when its temperature is T5 (to be sensed by a separate
thermocouple).

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Result:
The Stefan Boltzman constant was found out to be = _______________________ m/m
2
k

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4
.

Outcome:

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From this experiment, calculating the Stefan Boltzman Constant by using boltzman apparatus
is learnt and this experiment could be used in the areas such as IC engines, heat exchangers, Steam boilers,
Pressure Cookers, Fins, Motor bodies, etc. where the Stefan Boltzman Constant is to be found by using
boltzman apparatus.
.Applications:

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IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

Sl. No.
Hemisphere Temperature(
0

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C) Avg. Temp.
of the
Hemisphere
(Th)
T4

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Steady
Temp. of
Disc
T0 (Td)
Time

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(Sec) T1 T2 T3

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1. Define ? Emissive Power[E]
2. What are meant by black body?

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3. State Planck?s distribution law.
4. Define ? Biot Number
5. State Wien?s displacement law.
6. What is the significance of Biot Number?
7. State Stefan ? Boltzmann law.

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8. What are the various types of convection?
9. Define ? Condensation
10. What are the various modes of condensation?
11. Define ? Monochromatic Emissive Power[Eb ?]
12. What is meant by gray body?

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13. State Krichoff's law or radiation
14. What is meant by shape factor?
15. Explain the concept of black body.

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Viva ? voce

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45 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.9

DETERMINATION OF EMISSIVITY OF A GREY

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SURFACE

Aim:
To measure emissivity of the test plate surface at various temperature
Apparatus required:

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(i) Experimental setup
(ii) Thermocouples
(iii) U ? tube manometer
Theory:
The experiment set up consists of two circular aluminum plates identical in size and are provided with

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heating coils sandwiched. The plates are mounted on brackets and are kept in an enclosure so as to provide
undistributed natural convection surroundings. The heat input to the heater is varied by separate dimmer stats
and is measured by using an ammeter and voltmeter with the help of double pole double throw switch. The
temperatures of the plates are measured by thermocouples. Plates (1) is blackened by a thick layer of lamp
black to form the idealized black surface whereas the plate (2) is the test plate whose emissivity is to be

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determined.
Specifications:
1. Heater input to black plate W1 = V1 x I1 W
2. Heater input to test plate W2 = V2 x I2 W
3. Diameter of the plates (Aluminum) = 150 mm (Test plate and Black plate)

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4. Heater for (1) & (2) Nichrome strip wound on mica sheet and sandwiched between two mica sheets.
Capacity of heater = 200 W each
5. Voltmeter = 0 -100/200 V
6. Ammeter = 0-2 A
7. Dimmer stat for (1) & (2) 0 ? 2 A, 0 ? 260 V

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8. Enclosure size = 580 mm x 300 mm x 300 mm.
9. Thermocouples = Chromel Alumel ? 3 Nos.
10. Temperature Indicator = 0 ? 300
0
C.

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Precautions:
1. Keep the dimmer stat at zero position before switching ON the power supply.
2. Use proper voltage range on Voltmeter.
3. Gradually increase the heater inputs.

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4. Do not disturb thermocouples while testing.
5. Operate selector switch of temperature indicator gently.
6. See that the black plate is having a layer of lamp black uniformly.
Tabulation:
Sl.

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No
Voltage

Current

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Black body
temp(
0
C)
Avg.

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temp.

Polished body
temp (
0

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C)
Avg.
temp.

Enclosure

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Temp.
(V) (I) T5 T6 T7 Tb T1 T2 T3 Tp (T4)

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Formulae used:
Under steady state condition,
W1 ? W2 = (Eb ? E) ? (Ts
4
? Ta

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4
) A
Eb ? E = (W1 ? W2) / ? (Ts
4
? Ta

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4
) A
E = Eb ? {(W1 ? W2) / ? (Ts
4
? Ta

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4
) A}
Where,
W1 = Heater input to black plate = V1 x I1 W
W2 = Heater input to test plate = V2 x I2 W

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A = area of plates = 2 (?/4) xd
2
m
2

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T = Temperature of black plate, k = (Ts + Ta) / 2
Ta = Ambient temperature of enclosure
Ts = surface temperature of the discs (or T1)
Eb = Emissivity of black plate = 1
E = Emissivity of Test plate

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? = Stefan boltzman constant = 5.67 x 10
-8

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W/m
2
K
4

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Schematic view of the test set-up:


Procedure:

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1. Increase the input to the heater gradually to black plate and adjust it to some value viz. 30, 50, 75 watts.
And adjust the heater input to test plate slightly less than the black plate 27, 35, 55 watts etc.,
2. Check the temperature of the two plates with small time intervals and adjust the input of test plate only, by
the dimmer stat so that the two plates will be maintained at the same temperature.
3. Follow trial and error method and wait sufficiently (more than one hour or so) to obtain the steady state

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condition.

Results:
The emissivity of the test plate surface is found to be _____________.
Outcome:

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From this experiment, finding the emissivity of the test plate surface at various
temperatures is learnt and this experiment could be used in the areas such as IC engines, heat exchangers,
Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where emissivity is to be found.

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Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Emissivity
2. State Kirchoff?s law of radiation.
3. What is meant by reflectivity?
4. State Lambert?s cosine law.
5. What is the purpose of radiation shield?

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6. What is meant by shape factor?
7. Define ? Radiation
8. What is meant by monochromatic emissive power?
9. Define ? Emissive Power
10. What is meant by absorptivity?

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11. Define ? Black Body
12. What is meant by transmissivity?
13. State Plank's distribution law
14. What is meant by gray body?
15. Define ? Irradiation

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Viva ? voce

49 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.10

EFFECTIVENESS OF PARALLEL / COUNTER
FLOW HEAT EXCHANGE

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Aim:
To determine the values of effectiveness of heat exchanger for parallel and counter flow
Apparatus required:
(i) Experimental Setup
(ii) Stop watch

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(iii) Thermometer
Theory:
Heat exchangers are classified in three categories:
1. Transfer type
2. Storage type

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3. Direct contact type.
A transfer type of heat exchanger is one which both fluids pass simultaneously through the device and heat is
transferred through separating walls. In practice, most of the heat exchangers used are transfer type one.
The transfer type exchangers are further classified accordant to flow arrangements as:
i. PARALLEL FLOW in which fluids flow in the same direction.

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ii. COUNTER FLOW in which fluids flow in opposite direction.
iii. CROSS FLOW in which fluids flow at right angles to each other.
The apparatus consist of a tube in tube type concentric tube heat exchanger. The hot fluid is not water
which is obtained from an electric geyser and it flows through the inner tube while the cold fluid is cold water
flowing through the annulus. The hot water flows always in one direction and the flow rate is controlled by

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means of a gate vale. The cold water can be admitted at one of the ends enabling the heat exchanger to run
as a parallel flow apparatus or a counter flow apparatus. This is done by valve operations.
Specifications:
1. Inner tube material ? copper Internal diameter (I.D) = 12.0 mm
2. Inner tube material ? copper Internal diameter (O.D) = 15.0 mm

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3. Outer tube material ? G.I Internal diameter (I.D) = 40.0 mm
4. Length of the heat exchanger (L) = 1800 mm
5. Thermometers (for cold water) = 0 ? 50
0
C - 2 Nos.

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6. Thermometers (for hot water) = 0 ? 100
0
C - 2 Nos.
7. Measuring flask = 0 ? 1000 CC

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8. Geyser: single phase type to obtain hot water supply
9. Thermo Cole insulation for outer pipe.
Precautions:

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Start the cooling circuit before switching ON the heaters (geyser) and adjust the flow rate so that practically
there is no temperature rise in the circuiting fluid.
Tabulations:
Sl.
No.

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Flow Hot Fluid (
0
C) Cold Fluid (
0
C)

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Time for
collection of
hot fluid
Kg/sec
Time for

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collection
of cold fluid
Kg/sec
1 Parallel flow
Thi (T1) Tho (T2) Tci (T3) Tco (T4)

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2 Counter flow

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Formulae Used: (Parallel flow & Counter flow)
1. Area of the pipe A = ? (D ? d) L
Where, D = inlet diameter of the outer tube

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d = outlet diameter of the inner tube
L = Length of the tube

2. Heat transferred from hot water Qa = mcp (Thi ? Tho) W

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Where, m = mass flow rate Kg/ sec.
m = ?v/t, ? = density of water and t = time taken for hot water
Cp = Specific heat of capacity 4.187 kJ/kg -K

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Thi = Temperature of hot water inlet
Tho = Temperature of hot water outlet

3. Heat transfer from cold water Qc = mcp (Tco ? Tci) W
Where, m = mass flow rate

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Cp = Specific heat of capacity
Tco = Temperature of cold water inlet
Tci = Temperature of cold water outlet
4. Effectivesness, E = Q? / {mcp (Thi ? Tci)} W
Where, Q? = (Qa + Qc) / 2

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5. Logarithmic mean temperature difference( L M T D)
?Tm = (?Ti - ?To) / In (?Ti/?To)
Where, ?To = Tho ? Tco
?Ti = Thi ? Tci
6. Over all heat transfer coefficient

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h = Q?/?Tm A W/m
2
K
where Q? = (Qa + Qc) / 2

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Procedure:
1. Place the thermometers in position and note down their readings when they are at room temperature and
no water is flowing at either side. This is required to correct the temperature.
2. Start the flow on hot water side.
3. Start the flow through annulus and run the exchanger as parallel flow unit.

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4. Put ON the geyser.
5. Adjust the flow rate on hot water side, between the ranges of 1.5 to 4 L/min.
6. Adjust the flow rate on cold water side between ranges of 3 to 8 L/min.
7. Keeping the flow rates same, wait till the steady state conditions are reached.
8. Record the temperatures on hot water and cold water side and also the flow rates accurately.

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9. Repeat the experiment with a counter flow under identical flow conditions.
10. Correct the temperatures by suitable correction obtained from initial readings of thermometers.

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Result:
1. The values of effectiveness of heat exchanger were found as
(i) Parallel flow = ________.
(ii) Counter flow = _________.

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2. Over all heat exchanger (heat transfer coefficient)
(i) Parallel flow = ________.
(ii) Counter flow = _________.

Outcome:

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From this experiment, determining the values of effectiveness of parallel and counter flow
heat exchangers is learnt and this experiment could be used in the areas such as IC engines, heat
exchangers, Steam boilers, Pressure Cookers, Fins, Motor bodies, etc. where the effectiveness is to be found.
Applications:
IC engines, heat exchangers, Steam boilers, Pressure Cooker, Fins, Motor bodies.

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1. Define ? Heat Exchanger
2. What are the types of heat exchangers?

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3. What is meant by indirect contact heat exchanger?
4. Write about the merits of drop wise condensation.
5. What is meant by film wise and drop wise condensation?
6. What is meant by effectiveness?
7. Define ? Direct Heat Exchanger

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8. What is meant by fouling factor?
9. Distinguish between regenerator and recuperates.
10. What is meant by parallel flow heat exchanger?
11. What is meant by counter flow heat exchanger?
12. What is meant by cross flow heat exchanger?

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13. What is meant by shell and tube heat exchanger?
Viva ? voce

53 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.11

DETERMINATION OF COP OF A REFRIGERATION
SYSTEM

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Aim:
To conduct a load test on refrigeration test rig and determine the coefficient of performance of refrigeration
system
Apparatus required:
(i) Thermometer

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(ii) Electric Heater
(iii) Stop watch
(iv) Experimental setup
Description:
1. The test rig consist of compressor, condenser unit placed inside trolley and fitted with (i) R-134a

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reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for condenser and (iv) Liquid receiver.
2. The chilled water calorimeter consisting of a refrigerated stainless steel vessel placed inside an insulated
wooden box and provided with (i) Evaporative coil, (ii) Stirrer, (iii) Electric heater, (iv) Sensing bulb of a
low temperature thermostat, (v) A high temperature thermostat and (vi) A thermometer to measure the
temperature of chilled water. The above unit is located on the trolley behind front panel.

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3. The front panel of the test rig consist of (i) Capillary expansion tube with isolation valve, (ii) Thermostatic
expansion valve and solenoid thermostat, solenoid switch, indicator and isolating valve (iii) Drier cum
strainer and sight glass, (iv) Thermostat at inlet and outlet of both evaporator and condenser, (v) Pressure
gauge at inlet and outlet of evaporator and condenser,(vi) Main switch and compressor safety high
pressure / low pressure (HP/LP) cut-out, (vii) Heat power regulator switch and regulator, (viii) Energy

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meter to measure the power consumed either by hater or by compressor.

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Specifications:

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A. A compressor condenser unit placed inside trolley and fitted with
1. R-134a reciprocating compressor
2. Condenser
3. 0.5 hp, 220 V, single phase capacitor start induction motor with condenser cooling fan
4. A receiver with angle check valve

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B. Chilled water calorimeter consisting of a refrigerated S.S vessel of ample capacity
placed inside a well insulated wooden box and provided with
5. Evaporator coil
6. Stirrer
7. Electric heater 230 V, A.C.

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8. The sensing bulb of low temperature thermostat.
9. A high temperature thermostat.
10. A Thermometer to measure the chilled water temperature
C. The front panel on which are mounted the following
11. Capillary expansion tube with isolating valve.

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12. Thermostatic expansion valve and solenoid thermostat, solenoid switch, indicator
and isolating valve
13. Drier cum strainer and sight glass
14. Thermostat at inlet and outlet of both evaporator and condenser
15. Pressure gauge at inlet and outlet of evaporator and condenser

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16. Main switch and compressor safety high pressure / low pressure (HP/LP) cut-out
17. Heat power regulator switch and regulator
18. Energy meter to measure the power consumed either by hater or by compressor.

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Precautions:
1. Make sure that the three pin main cable is properly earthed to avoid any electrical shocks.

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2. The heater regulator should be switched off whenever not in use. Heating water beyond 40
0
C may lead to
permanent damage of the entire system. A high temperature cut off thermostat is provided in the water
chiller, to cut off the heater beyond 30

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0
C.Check the setting of the same before operation.
3. The (low pressure) LP cut-off is adjusted to cut on reading 10 psig. Do not alter this setting.
4. The (high pressure) HP cut-off is adjusted to cut at 280 psig. Do not alter this setting.
5. The solenoid thermostat is adjusted to cut at 15

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0
C and cut in at 10
0
C of the chilled water. Do not alter the
same.

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6. The main switch contains a fuse unit inside. The same has to be rewired if blown of.
7. The space near the condenser should permit good ventilation to aid proper fan performance.
8. The pressure gauges used are calibrated in psig: (the corresponding saturation temperature are marked
in
0

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F on the dial for Freon-22 and is irrelevant here. Reliable pressure gauges for Freon-12 use,
calibrated in SI units, are not available.)
9. Hence the reading should be converted into absolute (psia) units by adding 14.7 and dividing by 145 to
obtain the pressure in MN/m
2

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.e.g. P = x psig
= (x + 14.7) psia
= (x + 14.7) / 145 MN/m
2
(MPa)

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10. The water in the chiller is to be stirred properly for some time before taking readings T4 & T5.
Formulae used:
Let, State 1 indicates the entry of compressor.
State 2 indicates the exit of compressor.
State 3 indicates the exit from condenser.

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State 4 indicates the entry to evaporator
P = Pressure (bar)
T = Temperature (
0
C)

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H = Specific enthalpy (kJ/kg)
v = Specific Volume (m
3
/Kg)
n = Number of revolutions of energy meter disc.

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t1 = Time taken for ?n? revolutions of energy meter disc for heater (sec)
t2 = Time taken for ?n? revolutions of energy meter disc for compressor (sec)
K = Energy meter constant = 3200 lmp / kWh
N = Speed of compressor = 2840 rpm
h1 = Specific enthalpy of vapour at Pe and T1 (kJ/kg)

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h2 = Specific enthalpy at Pc and T2 (kJ/kg) assuming isomeric compression, i.e., s1 = s2
h3 = Specific enthalpy at Pc and T3 (kJ/kg)

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h4 = h3
Stroke volume of compressor = (?/ 4) d
2
l = 12.58 x 10
-6

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m
3

1. Average evaporator pressure, Pe = (P1 + P4) / 2 bar
2. Average condenser pressure, Pc = (P2 + P3) / 2 bar

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3. Heater input, Qe = (n / t1) x (3600 / k) kW
4. Compressor input, W = (n / t2) x (3600 / k) kW
5. Actual C.O.P = Heater input / Compressor input = Qe / W = t2 / t1
6. Theoretical C.O.P = (h1 ? h4) / (h2 ? h1)
7. Refrigeration flow rate, m = Qe / (h1 ? h4) kg/s

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Observation Table: I

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Sl.
No.

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Initial
Temp.
of water

Final

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Temp.
of water
Duration
of exp.

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Delivery
pressure

Delivery
Temp.

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Condense
Outlet
Pressure

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Condense
Outlet
Temp.

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Pressure
after
throttling

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Temp.
After

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Throttli
ng


Suction

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pressur
e
Suction
Temp.

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Time for
10 rev. of

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compress
or energy
meter

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Height
of water
in the
vessel

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58 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Procedure:
Load Test with Capillary tube as expansion device:
1. Fill the chilled water calorimeter with pure water so that the evaporative coils are

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fully immersed.
2. Select the capillary tube line by opening the shut-off valve on this line and closing
the one on the thermostatic expansion valve line. The solenoid switch is switched OFF.
3. Start the compressor and run for some time so that the chilled water temperature
is lowered to the given test temperature.

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4. Switch on the heater and slowly increase the power.
5. Allow The temperature in water calorimeter to reach the equilibrium
temperature.
6. Connect energy meter to motor and heater by the selector switch one after another
and note down the time taken for 10 pulses of the energy meter disc.

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7. Note down the pressure and temperature readings at locations 1,2,3 & 4 as
mentioned.
8. Switch OFF the heater and the mains.
Result:
The load test on a refrigeration test rig was conducted and the results are as follows.

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1. Actual C.O.P. of the system =____________.
2. Rhetorical C.O.P. of the system = ___________.
3. Volumetric Efficiency = ___________.

Outcome:

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From this experiment, conducting the load test on a refrigeration test rig and finding out the
volumetric efficiency and co-efficient of performance for any type of refrigerant is learnt and this experiment
could be used in the areas such as Refrigerator and Air Conditioning.
Applications:
Refrigerator, Air Conditioning.

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59 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Define ? COP
2. Which thermodynamic cycle is used in air conditioning of airplanes using air as refrigerant?

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3. Define ? Ton of Refrigeration
4. What is meant by refrigeration?
5. What is meant by air conditioning?
6. What are the four important properties of a good refrigerant?
7. How does the actual vapour compression cycle differ from that of the ideal cycle?

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8. Name any four commonly used refrigerants.
9. What are the expansion devices used in a vapour compression plant?
10. Why throttle valve is used in place of expansion cylinder for vapour compression refrigerant machine?
11. What are the merits of air refrigeration system?
12. What are the demerits of air refrigeration system?

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13. Define ? Refrigerant
14. What is net refrigerating effect of the refrigerant?
15. What are the methods to obtain sub cooling of refrigerant?

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Viva ? voce

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60 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Expt. No.12 EXPERIMENTS ON PSYCHROMETRIC PROCESS

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Aim:
To conduct an experiment on psychrometric processes with air conditioning system
Apparatus required:
(i) Thermometer
(ii) Electric Heater

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(iii) Stop watch
(iv) Digital anemometer
(v) Experimental setup
Description:
The test rig consist of

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1. An air duct support of stand
2. A blower to set up air flow through the duct along with a speed control to vary the
velocity of air.
3. A heater to rise the air temperature with regulator and energy meter.
4. Water spray, collecting tray, reservoir with gauge pump.

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5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.
(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after cooling coil).
6. The test rig consist of compressor, condenser unit placed inside trolley and fitted
with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan for
condenser and (iv) Liquid receiver.

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7. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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61 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00


Observation Table: I

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Precautions:
1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence
avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kw only for the motor
circuit.

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2. Natural air currents in the room if in the direction of air duct may defect the experimental results and
hence the duct should be placed such that no wind from doors, windows, fan and cooling air from
other test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan
and should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase
beyond 240 psi.

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3. Never exceed dry bulb temperatures of 40
0
C after the heater (station 2) otherwise the air duct may be
damaged.
4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may

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exceed its maximum of 32
0
C and calibration may be affected.
5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not
running this will lead to rise in temperature at the heater and may damage the heater and the air duct.

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6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their
duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.
7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer
is placed inside the reservoir at the top. This may have to the cleaned when necessary.
8. Do not open the gate valve fully otherwise water may be splashed outside and the waster

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measurement may be in error.
S.
N
o
Inlet temp

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Outlet
temp
Pressu
re
P1

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Tem
p.
T1
Pressu
re

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P2
Temp.
T2
Pressu
re

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P3

Tem
p.
T3

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Pressu
re
P4

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Temp.
T4
Energy

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for 10
revolutio
ns
Twet Tdry Twet Tdry Lb/in
o

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C Lb/in
o
C Lb/in
o
C Lb/in

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o
C


62 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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9. If the low pressure cut out comes in to action, it means that the Freon charge is insufficient and may
have to be filled up. The suction pressure should never go below 2 psi as otherwise the compressor
seals will be damaged and air and moisture may enter the system.
10. The refrigerant strainer placed on the front panel should always be warm. If it cools and moisture

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condenser on it, then the strainer might have to be charged by an experienced refrigeration
mechanics.
11. The refrigerating system can work continuously for 2 hours, however if the room temperature is above
25
0

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C the condenser may be heated up and the delivery pressure may rise. Do not exceed 240 psi.
Pour one or two glasses of drinking water over the fins of the condenser in order to reduce the
delivery pressure.
12. After some months of operation the compressor may have to be topped up with oil and some quantity
of Freon-22 may have to be charged by an experienced mechanics.

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13. See that distilled water is filled up in the plastic dishes provided under the wet bulb thermometers and
that the wicks are in tact otherwise erroneous readings may be obtained. These thermometers will
show correct readings only when the fan is in operation.
14. The inside of air duct and all metal parts should be painted at least once a year to avoid moisture and
corrosion damage.

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Formulae used:
1. Corresponding to the dry and wet bulb temperature at all the stations obtain the specific enthalpy and
specific humidity values from psychrometric chart.
i.e., h1 and w1 at tb1 and tw1 and so on.

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2. Air flow rate, ma = (A x V) / v4 Kg / sec
Where, A = Area of duct at outlet in m
2
(0.46 m x 0.086 m)
V = Air velocity ( m / sec)

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V4 = Specific volume of moist air at station 4 using psychometric chart m
3
/Kg
3. Moisture added from psychrometric chart, mw1 = ma (w3-w2) Kg / sec.
Where, w3 = Specific humidity at station 3

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w2 = Specific humidity at station 2
4. Cooling effect produced on air, Qe = ma (h3 ? h4) kW.
Where, h3 = Specific enthalpy at state 3 kJ/kg
h4 = Specific enthalpy at state 4 kJ/kg
5. Moisture condensed, mcl = ma (w3 ? w4) kg/sec

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Where, w3 = Specific humidity at station 3
w4 = Specific humidity at station 4

63 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Procedure:
1. Fill water in the wet bulb temperature probe trays.
2. Start the main.
3. Start the blower and run it the required speed by keeping the speed regulator at
position.

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4. Start the spray pump and open the gate valve suitably.
5. Start the heater.
6. Select the expansion device (Capillary tube / Thermostatic expansion valve)
7. Start the cooling compressor.
8. Wait for some time till thermometers shown practically constant readings and note down the

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following readings:
(i) Dry bulb temperatures tdb1, tdb2, tdb3, tdb4.
(ii) Wet bulb temperatures twb1, twb2, twb3, twb4.
(iii) Spray water temperature, ts
(iv) Surface temperature of cooler, tm ( at control panel)

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(v) Pressure gauge reading, pd ( at control panel)
(vi) Compound gauge reading, Ps ( at control panel)
(vii) Level reduction?l? in spray reservoir (mm) during 5 min.
(viii) Amount of condensate collected ?lc?, in a measuring jar at cooler tray during a
run of 5 minutes at constant conditions.

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(ix) Time in second ?SH? for 10 pulses of the energy meter disc connected to the
heater.
(x) Time in seconds Sc for 10 pulses of the energy meter disc connected to cooler
compressor.
Result:

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Experiment on psychrometric processes with air conditioning system was drawn
Outcome:
From this experiment, conducting the test on psychrometric processes with air
conditioning system is learnt and this experiment could be used in all types of air conditioning systems.

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Applications:
Air Conditioning.

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64 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00



1. What is the commonly used unit of refrigeration?

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2. Distinguish between summer air conditioning and winter air conditioning.
3. Define ? RSHF Line
4. Define ? By Pass Factor of a Heating Coil
5. What is the effect of sub cooling a refrigerant in a vapour compression cycle?
6. What is the function of analyzer and rectifier in an absorption system?

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7. What is the purpose of generator assembly in vapour absorption refrigeration system?
8. State the substance used in the Lithium Bromide system and their functions.
9. Differentiate wet compression from dry compression.
10. Define ? Apparatus Dew Point
11. What is meant by dew point temperature?

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12. Define ? Wet Bulb Temperature
13. Define ? Degree of Saturation
14. What is meant by specific humidity?
15. Define ? Relative Humidity

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Viva ? voce

65 Format No.: FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.13

PERFORMANCE TEST ON A RECIPROCATING
AIR COMPRESSOR

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Aim:
To conduct a load test on the 2 - stage reciprocating air compressor to determine the isothermal and
volumetric Efficiencies at various delivery pressures

Apparatus required:

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* Air compressor with accessories.
* Stop watch.
Description:
Two stage air compressors is a reciprocating type driven by a prime mover. The test rig consist of a base on
which the tank is mounted. The outlet of the compressor is connected to the receiver. The suction is

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connected to air tank with a calibrated orifice plate through a water manometer. The input to the motor is
recorded by an energy meter. The temperature and pressure of the air compressed is indicated by a
thermometer and pressure gauge.
Specifications:
1. Air compressor:

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* LP Bore, DLP = 63.0 mm.
* HP Bore, DHP = 79.0 mm.
* Stroke, L = 80.0 mm.
* Speed, N = 1440 rpm (5 HP)
* Effective radius = 0.193 m

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2. Air receiver capacity = 0.33 m3
3. Orifice, diameter, d0 = 12 mm
4. Orifice area,. A0 : ?d0
2
/ 4 = ----------- m

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2

5. Coefficient of discharge C d. = 0.6
6. Energy-meter constant = 200 rev / kWh

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66 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

Observation Table: II

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Sl.
No.
Actual
Discharge
Va

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Theoritical
Discharge
Vt
Volumetric
Efficiency

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?
Power
Input

Output

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Power

Overall
Efficiency
?0

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Isothermal
Workdone
IwD
Polytropic
Workdone

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PwD
Isothermal
Efficiency
?iso
m

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3
/sec m
3
/sec % kW kW % J/Kg J/Kg %

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Sl.
No.
Pressure
p

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Manometer
h1
Manometer
h2
Time for 5 revolutions Energy meter Speed of the compressor Temperature

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T1
Temperature
T1
Kg/cm
2

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Cm cm sec rpm
o
C
o
C

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67 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Precautions:
1. Check whether manometer is filled with water up to the required level.
2. The maximum pressure in the receiver tank should not exceed 12 kg / cm
2

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Procedure:
1. Ensure that gauge pressure in the tank is zero.
2. Start the compressor. Read the receiver pressure gauge for a particular pressure.
3. Maintain the pressure constant by adjusting the outlet valve.
4. Note down the manometer reading and time taken for 3 revolution of the energy

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Formulae used:
1. Density of air at RTP:
? RTP = ? NTP X 273 Kg/ m
3

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(273 + Room Temp)
Where density of air at NTP = 1.293 Kg/ m
3
.

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2. Air head causing flow:
ha RTP = (h1 - h2) x ? water m
?a RTP
Where,
(h1- h2) = Difference in manometer liquid, in m.

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3. Actual volume at RTP:
Va RTP = C.d x Ao x ? 2 g ha RTP
Where,
C d= Coefficient of discharge = 0.6.

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A o = Area of orifice = ?(d0)
2
m
2
.

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4
Diameter of orifice d o = 0.01 m.
4. Actual volume at NTP:
Va NTP = VaRTP x T NTP
T RTP

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Where,
T NTP = Normal temp - 273
o
k
T RTP = Room temp -

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o
c (273 + TROOM )

68 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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5. Theoretical Volume of air: (at intake conditions)
V T = ?D
2
x L x Nc m
3

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/ sec.
4 x 60
D = LP Bore diameter = 88.5 mm.
L = Stroke length = 88.9 mm.
Nc = Compressor speed rpm.

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6. Volumetric Efficiency:(for LP stage)
?vol = Va NTP x 100%
Vt
7. Shaft Input through Energy meter:

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= 1 x n x ?t x ?m x 3600 kw.
( Ec x t )
Where,
Ec = Energy meter constant = 200 rev / kWh
?t = Efficiency for transmission = 0.95.

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? m = Efficiency for motor = 0.90.
t = Time for 'n' revolution of energy meter disc.
n = no. of rev. of Energy meter disc.

8. Isothermal power:

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= Pa x Va RTP x log e (R) W
1000
Pa = Atmospheric pressure in N/ m
2
= 1.01325 x 10

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5
N / m
2
.
R = (Pressure gauge reading + atmospheric pressure)

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atmospheric pressure.
9. Isothermal efficiency:
? ISO = Isothermal power x 100%
Shaft input

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Result:
The values of isothermal and volumetric efficiency at various delivery pressures have been studied &
graph between Pressure Vs Volumetric efficiency and Pressure Vs Isothermal efficiency are drawn.

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69 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Outcome:
From this experiment, conducting the load test on two stage reciprocating air compressor for
determining the isothermal and volumetric Efficiencies at various delivery pressures is understood and this

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experiment could be used in the areas such as Refrigerator, Air Conditioning, IC engines, etc.

Applications:
Refrigerator, Air Conditioning, IC engines.

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1. How are air compressors classified?
2. Define ? Isothermal Efficiency of Air Compressor
3. What is meant by FAD (Free Air Delivery)?
4. What is meant by perfect inter-cooling?

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5. Define ? Clearance Ratio of an Air Compressor
6. List out the applications of compressed air.
7. What are the types of air compressors?
8. What is meant by single acting compressor?
9. What is meant by double acting compressor?

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10. What is meant by single stage compressor?
11. What is meant by multi stage compressor?
12. Indicate the applications of reciprocating compressors in industry>
13. Define ? Mechanical Efficiency
14. What is meant by compression ratio?

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15. What are the factors that affect the volumetric efficiency of a reciprocating compressor?

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Viva ? voce

70 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.14

PERFORMANCE TEST IN A HC REFRIGERATION
SYSTEM

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Aim:

To conduct the performance test on Vapour Compression Refrigeration System and to determine the

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Coefficient of Performance using solenoid valve by throttling method

Description:

In this system the working fluid is a HC out of a refrigeration system. The HC compression system is most

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important system from the view point of commercial and domestic utility. The HC refrigerant at low temp and
pressure enters the reciprocating compressor, where it is compressed isentropically and subsequently its temp
and pressure increases considerably. This HC after leaving the compressor enters the condenser where it is
cooled into low temperature. Then it is sucked by reciprocating compressor and is thus repeated.
Formula used:

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Actual COP = refrigerant effect
I/p energy to compressor
Refrigerant effect = mxCpx ? T
t

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m - mass of water (kg)
Cp - Sp. Heat of water (4.2 kJ/kg K)
?T ? decrease in temp (Ti-Ts)
t - timetaken duration of expt (sec)

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Energy input =n x 3600 /k x t
n ? number of revolutions in energy meter
t ? time taken of ?n? revolutions
k ? energy meter constant (3200)

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71 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Tabulation:

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Pressure of the refrigerant (Mpa) Temperature Time for n?
rev of
energy
meter in
sec

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P1 P2 P3 P4 Circulating fluid
temp
Refrigerant temp

Ti Tf T1 T2 T3 T4

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72 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Model calculation:

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Actual COP = refrigerant effect
I/p energy to compressor

Refrigerant effect = mxCpx ? T
t

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m - mass of water (kg)
Cp - Sp. Heat of water (4.2 kJ/kg K)
?T ? decrease in temp (Ti-Ts)
t - time taken duration of experiment (sec)
Refrigerating effect = 8x4.2x (27-6)/1200=0.588 kw

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Energy input = n x 3600
n ? Number of revolutions in energy meter
t ? Time taken of ?n? revolutions
k ? Energy meter constant

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=3 x 3600/(1200 x 54)
=0.166 kW
Actual COP = refrigerant effect
I/p energy to compressor
= 0.588/0.166

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=3.526
Result:

The experiment was conducted successfully and coefficient of performance was found out is _______.

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Outcome:
From this experiment, conducting the performance test on Vapour Compression Refrigeration
System and to determine the Coefficient of Performance using solenoid valve by throttling method is
understood and this experiment could be used in the areas such as Refrigerator and Air Conditioning systems.
Applications:

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Refrigerator, Air Conditioning.

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73 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is the difference between air conditioning and refrigeration?
2. Write any three important properties of a good refrigerant.
3. What is the function of analyzer and rectifier in an absorption system?
4. How does humidity affect human comfort?

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5. What is the commonly used unit of refrigeration?
6. Distinguish between summer air conditioning and winter air conditioning.
7. Define ? RSHF Line
8. Define ? By Pass Factor of a Heating Coil
9. What is the effect of sub cooling a refrigerant in a vapour compression cycle?

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10. What is the function of analyzer and rectifier in an absorption system?
11. What is the purpose of generator assembly in vapour absorption refrigeration system?
12. State the substance used in the Lithium Bromide system and their functions.
13. Differentiate wet compression from dry compression.
14. Define ? Apparatus Dew Point

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15. What is meant by dew point temperature?
16. Define ? Wet Bulb Temperature
17. Define ? Degree of Saturation
18. What is meant by specific humidity?
19. Define ? Relative Humidity

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20. What is meant by dew point temperature?

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Viva ? voce

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74 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Expt. No.15

PERFORMANCE TEST IN A FLUIDIZED BED

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COOLING SYSTEM

Aim:
To determine the performance test on cooling tower
Introduction:

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The cooling tower is one of the most important device in chemical industries for example when the hot
water come from heat exchanger we use the cooling tower to cool it The purpose of cooling tower is to cool
relatively warm water by contacting with unsaturated air. The evaporation of water mainly provides cooling. In
typical water cooling water tower warm water flows countercurrent to an airstream. Typically, the warm water
enters the top of the packed tower and cascades down through the packing , leaving at the bottom Air enters

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at the bottom of the tower and flows upward through the descending water . The tower packing often consist of
slats of plastic or of packed bed. The water is distributed by troughs and overflows to cascade over slat
gratings or packing that provides large interfacial areas of contact between the water and air in the form of
droplets and films of water. The flow of air upward through the tower can be induced by the buoyancy of the
warm air in the tower (natural draft) or by the action of a fan . The water cannot be cooled below the wet bulb

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temperature. The driving force for the evaporation of water is approximately the vapour pressure of the water
less the vapour pressure it would have at the wet bulb temperature
Procedure:
1. Introduce water and record its flow rate.
2. Switch ON the heaters on so that water is heated to the required temperature.

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3. Introduce air and record its flow rate.
4. Wait for steady state then record steady state dry and wet bulb temperature of air at the entrance and
exit.
5. Record the inlet and outlet temperature and flow rate of water also record temperature at different
stages.

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Tabulation:

Sl.No. T1 (
0
c) T2 (

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0
c) T3 (
0
c) Efficiency

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T1 = room temperature

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75 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

T2 = water inlet
T3 = water outlet

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Efficiency of cooling tower

ECT = T3/T2/*100

Model calculation:

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Efficiency of cooling tower = water outlet
--------------- *100
Water inlet

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= 36/40 *100

= 90
Result:
The performance test in cooling tower is determined as ______%.

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Outcome:
From this experiment, conducting the performance test on cooling tower is understood and this
experiment could be used in various power plants where cooling tower is used.
Applications:
Power Plant Cooling Tower, Cooling Tower.

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1. What are functions of a draught system?
2. What are the advantages of burning coal in pulverized form?
3. What are the functions of cooling tower?

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4. What are the different types of draught system?
5. What are the methods used for handling of coal?
6. What is meant by fluidized bed combustion?
7. What is the use of fluidized bed boiler?
8. What are the types of fluidized bed boiler?

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9. State the purpose of condenser in fluidized bed boiler.
10. What is meant by pulveriser and why it is used?
11. State the disadvantages of pulverized coal firing.
12. Distinguish between fouling and slagging.
Viva ? voce

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76 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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ADDITIONAL EXPERIMENTS
BEYOND THE SYLLABUS

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77 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Expt. No.16 AIR CONDITIONING TEST RIG

Aim:
To conduct a performance test on air conditioning test rig and determine the Coefficient of Performance of
air conditioning system

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Apparatus required:
(i) Thermometer
(ii) Electric Heater
(iii) Stop watch
(iv) Digital anemometer

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(v) Experimental setup
Description:
The test rig consist of
1. An air duct support of stand
2. A blower to set up air flow through the duct along with a speed control to vary the

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velocity of air.
3. A heater to rise the air temperature with regulator and energy meter.
4. Water spray, collecting tray, reservoir with gauge pump.
5. Wet and dry bulb bi-metallic dial type thermometer at stations 1, 2,3 &4.
(i.e., before heater, after heater or before sprayer, after sprayer or before cooing coil, after

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cooling coil).
6. The test rig consists of compressor, condenser unit placed inside trolley and fitted
with (i) Freon-22 (CCI2F2) reciprocating compressor (ii) Air cooled condenser, (iii) Cooling fan
for condenser and (iv) Liquid receiver.

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78 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Observation Table: I

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Air conditioning Test Rig

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Sl.
No

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Inlet
temperat
ure

Outlet

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temperatu
re

Pressu
re

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P1

Tem
p.
T1

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Pressu
re
P2
Temp.

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T2

Pressu
re
P3

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Tem
p.
T3

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Pressu
re
P4

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Tem
p.
T4

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Energy for
10
revolutions
Twet Tdry Twet Tdry Lb/in
o

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C Lb/in
o
C Lb/in
o
C

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Lb/in
o
C

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79 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

Precautions:
1. In case of low voltage motor may be overloaded, get heated up and the coils may be burnt up. Hence

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avoid operation at voltage less than 220 V. If necessary use a stabilizer of 2 kW only for the motor circuit.
2. Natural air currents in the room if in the direction of air duct may defect the experimental results and
hence the duct should be placed such that no wind from doors, windows, fan and cooling air from other
test rigs are directly incline with the duct. Any cross currents should only aid the condenser fan and
should not oppose it as otherwise the delivery pressure of the refrigerating systems will increase beyond

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240 psi.
3. Never exceed dry bulb temperatures of 40
0
C after the heater (station 2) otherwise the air duct may be
damaged.

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4. Do not operate heater without operating cooler also, otherwise the vapour pressure thermometer may
exceed its maximum of 32
0
C and calibration may be affected.
5. Fan is connected to the main switch so that it is always in operation. Never operate when fan is not

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running this will lead to rise in temperature at the heater and may damage the heater and the air duct.
6. After completing experiments always allow the fan only to operate for at least 15 minutes so that their
duct is cooled to room temperature and is also dried, otherwise the duct will be damaged.
7. Never run the pump without water in the reservoir, otherwise pump seals will be damaged. A strainer is
placed inside the reservoir at the top. This may have to the cleaned when necessary.

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8. Do not open the gate valve fully otherwise water may be splashed outside and the waster measurement
may be in error.
9. If the low pressure cut out comes in to action, it means that the Freon charge is insufficient and may have
to be filled up. The suction pressure should never go below 2 psi as otherwise the compressor seals will
be damaged and air and moisture may enter the system.

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10. The refrigerant strainer placed on the front panel should always be warm. If it cools and moisture
condenser on it, then the strainer might have to be charged by an experienced refrigeration mechanics.
11. The refrigerating system can work continuously for 2 hours, however if the room temperature is above
25
0

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C the condenser may be heated up and the delivery pressure may rise. Do not exceed 240 psi. Pour
one or two glasses of drinking water over the fins of the condenser in order to reduce the delivery
pressure.
12. After some months of operation the compressor may have to be topped up with oil and some quantity of
Freon-22 may have to be charged by an experienced mechanics.

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80 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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Formulae used:
1. Corresponding to the dry and wet bulb temperature at all the stations obtain the specific enthalpy and
specific humidity values from psychometric chart.
i.e., h1 and w1 at tb1 and tw1 and so on.

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2. Air flow rate, ma = (A x V) / v4 kg / sec
Where, A = Area of duct at outlet in m
2
(0.46 m x 0.086 m)
V = Air velocity ( m / sec)

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V4 = Specific volume of moist air at station 4 using psychometric chart m
3
/kg
3. Heat added, Q1 = ma (h2 ? h1) kW
Where, h1 = Specific enthalpy at station 1 kJ/kg

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h2 = Specific enthalpy at station 2 kJ/kg

4. Moisture added from psychrometric chart, mw1 = ma (w3-w2) Kg / sec.
Where, w3 = Specific humidity at station 3
w2 = Specific humidity at station 2

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5. Compressor power, W = (n / t) x (3600 / k) kW.
Where, n = No. of pulses of energy meter disc
t = Time taken for ?n? no. of pulses (sec)
k = Energy meter constant (3200 lmp / kW-hr)
6. Actual C.O.P = Cooling effect produced on air / Compressor power.

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7. Cooling effect produced on air, Qe = ma (h3 ? h4) kW.
Where, h3 = Specific enthalpy at state 3 kJ/kg
h4 = Specific enthalpy at state 4 kJ/kg
8. Moisture condensed, mcl = ma (w3 ? w4) Kg/sec
Where, w3 = Specific humidity at station 3

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w4 = Specific humidity at station 4
9. Draw the psychrometric process.

Procedure:
1. Fill water in the wet bulb temperature probe trays.

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2. Start the main.
3. Start the blower and run it the required speed by keeping the speed regulator at position.
4. Start the spray pump and open the gate valve suitably.
5. Start the heater.

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81 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

6. Select the expansion device (Capillary tube / Thermostatic expansion valve)
7. Start the cooling compressor.
8. Wait for some time till thermometers shown practically constant readings and note down the following

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readings:
(ii) Dry bulb temperatures tdb1, tdb2, tdb3, tdb4.
(ii) Wet bulb temperatures twb1, twb2, twb3, twb4.
(xi) Spray water temperature, ts
(xii) Surface temperature of cooler, tm ( at control panel)

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(xiii) Pressure gauge reading, pd ( at control panel)
(xiv) Compound gauge reading, Ps ( at control panel)
(xv) Level reduction?l? in spray reservoir (mm) during 5 min.
(xvi) Amount of condensate collected ?lc?, in a measuring jar at cooler tray during a
run of 5 minutes at constant conditions.

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(xvii) Time in second ?SH? for 10 pulses of the energy meter disc connected to the
heater.
(xviii) Time in seconds Sc for 10 pulses of the energy meter disc connected to cooler

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1. Repeat the above procedures for four more different settings of the fan Regulator (Position 1,2,3,4 & 5). If
sensible cooling range is narrow, then switch off the spray and repeat as above. If the atmosphere is cool,
the heater may be set for greater dissipation. If more readings are required for cooling below dew point
and dehumidification switch off heater and repeat procedure.
Result:

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The Load test on the AIR CONDITIONING TEST RIG was conducted and the results are as follows.
1. Actual C.O.P of the system = ______________.
Outcome:
From this experiment, conducting the performance test on air conditioning test rig and
determining the Coefficient of Performance of air conditioning system is understood and this experiment could

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be used in the areas such as Refrigerator and Air Conditioning systems.
Applications:
Refrigerator, Air Conditioning.

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82 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. What is meant by dew point temperature?
2. Define ? Effective Temperature
3. Define ? COP of Refrigeration
4. Define ? Relative Humidity and Wet Bulb Temperature

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5. Differentiate heat pump from refrigerator.
6. Define ? RSHF Line
7. Define ? By Pass Factor of a Heating Coil
8. What is the effect of sub cooling a refrigerant in a vapour compression cycle?
9. What is the function of analyzer and rectifier in an absorption system?

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10. What is the purpose of generator assembly in vapour absorption refrigeration system?
11. State the substance used in the Lithium Bromide system and their functions.
12. Differentiate wet compression from dry compression.
13. Define ? Apparatus Dew Point
14. What is meant by dew point temperature?

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15. Define ? Wet Bulb Temperature

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Viva ? voce

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83 Format No:FirstRanker/S tud/LM/34/Issue: 00/Revision: 00

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1. Waste heat recovery system from domestic refrigerator for water and air heating
2. Waste heat recovery system from domestic refrigerator for oven
3. Numerical Investigation and Statistical Analysis on Tree Shaped Fin for Natural Convection
4. CFD and Taguchi Analysis on Tree Fin for Natural Convection
5. The rate of heat transfer of seawater and NaCl solutions under conditions of one- and two-phase flow

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in tubes
6. Experimental analysis of emission characteristics in spark ignition engines at the presence of ortho
hydrogen
7. Solar Energy for Cooling and Refrigeration
8. Thermal analysis and design of shell and heat type heat exchanger

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9. Thermodynamic analysis of refrigeration system including all parts
10. Thermal analysis of air conditioner to decide its COP
11. Thermal design of domestic refrigerator to improve the performance
12. Performance analysis of a gasket plate heat exchanger by varying port diameter
13. Theoretical performance of magnetic hydrodynamics power plant with aluminum as fuel

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14. Investigation on performance characteristics of blended biodiesel with multifunctional additives
15. Performance analysis of basin type solar still under the effect of vacuum pressure

Project Work

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