Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2019 Winter 6th Sem Old 160202 Automobile Heat Transfer Previous Question Paper
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ? VI (Old) EXAMINATION ? WINTER 2019
Subject Code: 160202 Date: 16/12/2019
Subject Name: Automobile Heat Transfer
Time: 02:30 AM TO 05:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Distinguish between the conduction, convection and radiation heat transfer. 07
(b) Derive the general heat conduction equation in Cartesian coordinates. 07
Q.2 (a) Explain the following terms.
a) Efficiency of fin
b) Effectiveness of fin
c) Biot number
07
(b) Write a short on Radiator used in Car including construction, working and
application.
07
OR
(b) It is required to heat oil to about 300
o
C for frying purpose. A ladle is used in the
frying. The section of the handle is 5 mm x 18 mm. the surrounding are at 30
o
C.
The conductivity of the material is 205 W/m
o
C. If the temperature at a distance of
380 mm from the oil should not reach 40
o
C, determine the convective heat transfer
coefficient.
07
Q.3 (a) Write short notes on the following: (a) Absorptivity, (b) Grey body, (c) Intensity of
radiation and, (d) Black body.
07
(b) Derive Von-Karman integral momentum equation for hydrodynamic boundary
layer over a flat plate.
07
OR
Q.3 (a) The effective temperature of a body having an area of 0.12 m2 is 527 oC. Calculate
the following:
1. The total rate of energy emission
2. The intensity of normal radiation
3. The wavelength of maximum monochromatic emissive power.
07
(b) State any three laws of radiation. 07
Q.4 (a) What are the functions of cap which is used on a radiator? Explain construction and
working of a radiator cap.
07
(b) In a Counter flow type double pipe, HE, water is heated from 25
o
C to 65
o
C by an
oil with specific heat 1.45 KJ/kg K and mass flow rate of hot water is 0.9 KJ/s. the
oil is cooled from 230
o
C to 160
o
C. If the overall HT coefficient is 420 W/m
2 o
C.
Calculate, the rate of Heat transfer, the mass flow rate of water and the surface area
of Heat exchanger.
07
OR
Q.4 (a) Explain the following terms:
a) NTU
07
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1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ? VI (Old) EXAMINATION ? WINTER 2019
Subject Code: 160202 Date: 16/12/2019
Subject Name: Automobile Heat Transfer
Time: 02:30 AM TO 05:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Distinguish between the conduction, convection and radiation heat transfer. 07
(b) Derive the general heat conduction equation in Cartesian coordinates. 07
Q.2 (a) Explain the following terms.
a) Efficiency of fin
b) Effectiveness of fin
c) Biot number
07
(b) Write a short on Radiator used in Car including construction, working and
application.
07
OR
(b) It is required to heat oil to about 300
o
C for frying purpose. A ladle is used in the
frying. The section of the handle is 5 mm x 18 mm. the surrounding are at 30
o
C.
The conductivity of the material is 205 W/m
o
C. If the temperature at a distance of
380 mm from the oil should not reach 40
o
C, determine the convective heat transfer
coefficient.
07
Q.3 (a) Write short notes on the following: (a) Absorptivity, (b) Grey body, (c) Intensity of
radiation and, (d) Black body.
07
(b) Derive Von-Karman integral momentum equation for hydrodynamic boundary
layer over a flat plate.
07
OR
Q.3 (a) The effective temperature of a body having an area of 0.12 m2 is 527 oC. Calculate
the following:
1. The total rate of energy emission
2. The intensity of normal radiation
3. The wavelength of maximum monochromatic emissive power.
07
(b) State any three laws of radiation. 07
Q.4 (a) What are the functions of cap which is used on a radiator? Explain construction and
working of a radiator cap.
07
(b) In a Counter flow type double pipe, HE, water is heated from 25
o
C to 65
o
C by an
oil with specific heat 1.45 KJ/kg K and mass flow rate of hot water is 0.9 KJ/s. the
oil is cooled from 230
o
C to 160
o
C. If the overall HT coefficient is 420 W/m
2 o
C.
Calculate, the rate of Heat transfer, the mass flow rate of water and the surface area
of Heat exchanger.
07
OR
Q.4 (a) Explain the following terms:
a) NTU
07
2
b) Effectiveness of heat exchanger
c) Overall heat transfer coefficient.
(b) Derive an expression for logarithmic mean temperature difference (LMTD) for
Parallel flow heat exchanger.
07
Q.5 (a) What are the functions of cap which is used on a radiator? Explain construction and
working of a radiator cap.
07
(b) Explain the circumstances under which natural convection occurs. Differentiate
between natural and forced convection.
07
OR
Q.5 (a) Using Buckingham?s ? theorem, show that the free convection is given by Nu= ?
(Gr.) (Pr.)
07
(b) Write a short note on heat pipe stating principle of operation, types and applications. 07
*************
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This post was last modified on 20 February 2020