Download Visvesvaraya Technological University (VTU) BE ( Bachelor of Engineering) ME (Mechanical Engineering) 2017 Scheme 2020 January Previous Question Paper 4th Sem 17ME43 Applied Thermodynamics
USN
17ME43
Fourth Semester B.F.. Degree Examination, Dee.2019/Jan.2020
Applied Thermodynamics
Time: 3 hrs. Max. Marks: 100
Note: 1. Answer any FIVE full questions, choosing ONE full question from each module.
2. Use of thermodynamics data hand book is permitted.
c'
a.
Module-1
1 a. Show the compression ratio (r
e
) for maximum work should be per kg of air in an Otto cycle
L '
3
( \ 2(7-1)
between upper and lower limits of absolute temperature T3 and T3 is given r
(
.
1)
and also show that T
2
T
4
= (T, T
3
)
1 2
(10 Marks)
Compression ratio of diesel cycle is 14 and cut off ratio is 2.2 at beginning of cycle, air is
0.98 bar and 100?C. Find: (i) The temperature and pressure at salient points
(ii) Air standard efficiency. (10 Marks)
CS cci
:45
"
and the cycle efficiency. Assume the value of Cp = 1.005 kJ/kgK and y = 1.4. (10 Marks)
:... =
7::?:.
- i
Module-2 ,
a
3 a. Discuss with the help of T-S diagram the effect of Boiler pressure, condenser pressure and
,;- ..
o.
3-
= ?
super heat on the performance of a Rankine cycle. (10 Marks)
?
o.,
o cz
b. A 40 MW steam power plant working on Rankine cycle operator between boiler pressure of
C.) d'
e .9-
40 bar and condenser pressure of 0.1 bar. Steam leaves the boiler and enters the turbine at
400?C. The isentropic efficiency of steam turbine is 84%. Determine:
g i
i) Efficiency ii) Quality of exhaust iii) Steam flow rate in kg/hr.
. .
(10 Marks)
- -o
>,
= WI
?
?
a
w
E '>
o ?.. .).
8
?
Q.)
0
z
0
0.
= e' I
7
; F
-1)
OR
. .
?
T.
2 a. With a neat sketch, explain the working of Ramjet. (10 Marks)
E . 5
b.
In an open cycle gas turbine plant, air enters the compressor at I bar and 27?C. The pressure
r
A
0 1 after compression is 4 bar. The isentropic efficiencies of the turbine and the compressor are
(-)
(
L
)
8
85% and 80% respectively. Air fuel ratio is 80:1 calorific value of the fuel used is
? ?
? .0 42000 kJ/kg. Mass flow rate of air is 2.5 kg/sec. Determine the power output from the plant
to =
OR
4 a. A steam power plant operates on a theoretical reheat cycle. Steam at boiler outlet 150 bar,
550?C expands through the high pressure turbine. It is reheated at a constant pressure of 40
bar to 550?C and expands through the low pressure turbine to a condenser at 0.1 bar. Draw
T-S and h-s diagrams. Find:
(i) Quality of steam at turbine exhaust
(ii) Cycle efficiency
(iii) Steam rate in kg/KWh. (10 Marks)
b. With the help of neat diagram, explain the working of regenerative Rankine cycle and derive
the efficiency of the cycle. (10 Marks)
FirstRanker.com - FirstRanker's Choice
USN
17ME43
Fourth Semester B.F.. Degree Examination, Dee.2019/Jan.2020
Applied Thermodynamics
Time: 3 hrs. Max. Marks: 100
Note: 1. Answer any FIVE full questions, choosing ONE full question from each module.
2. Use of thermodynamics data hand book is permitted.
c'
a.
Module-1
1 a. Show the compression ratio (r
e
) for maximum work should be per kg of air in an Otto cycle
L '
3
( \ 2(7-1)
between upper and lower limits of absolute temperature T3 and T3 is given r
(
.
1)
and also show that T
2
T
4
= (T, T
3
)
1 2
(10 Marks)
Compression ratio of diesel cycle is 14 and cut off ratio is 2.2 at beginning of cycle, air is
0.98 bar and 100?C. Find: (i) The temperature and pressure at salient points
(ii) Air standard efficiency. (10 Marks)
CS cci
:45
"
and the cycle efficiency. Assume the value of Cp = 1.005 kJ/kgK and y = 1.4. (10 Marks)
:... =
7::?:.
- i
Module-2 ,
a
3 a. Discuss with the help of T-S diagram the effect of Boiler pressure, condenser pressure and
,;- ..
o.
3-
= ?
super heat on the performance of a Rankine cycle. (10 Marks)
?
o.,
o cz
b. A 40 MW steam power plant working on Rankine cycle operator between boiler pressure of
C.) d'
e .9-
40 bar and condenser pressure of 0.1 bar. Steam leaves the boiler and enters the turbine at
400?C. The isentropic efficiency of steam turbine is 84%. Determine:
g i
i) Efficiency ii) Quality of exhaust iii) Steam flow rate in kg/hr.
. .
(10 Marks)
- -o
>,
= WI
?
?
a
w
E '>
o ?.. .).
8
?
Q.)
0
z
0
0.
= e' I
7
; F
-1)
OR
. .
?
T.
2 a. With a neat sketch, explain the working of Ramjet. (10 Marks)
E . 5
b.
In an open cycle gas turbine plant, air enters the compressor at I bar and 27?C. The pressure
r
A
0 1 after compression is 4 bar. The isentropic efficiencies of the turbine and the compressor are
(-)
(
L
)
8
85% and 80% respectively. Air fuel ratio is 80:1 calorific value of the fuel used is
? ?
? .0 42000 kJ/kg. Mass flow rate of air is 2.5 kg/sec. Determine the power output from the plant
to =
OR
4 a. A steam power plant operates on a theoretical reheat cycle. Steam at boiler outlet 150 bar,
550?C expands through the high pressure turbine. It is reheated at a constant pressure of 40
bar to 550?C and expands through the low pressure turbine to a condenser at 0.1 bar. Draw
T-S and h-s diagrams. Find:
(i) Quality of steam at turbine exhaust
(ii) Cycle efficiency
(iii) Steam rate in kg/KWh. (10 Marks)
b. With the help of neat diagram, explain the working of regenerative Rankine cycle and derive
the efficiency of the cycle. (10 Marks)
17N.
Module-3
5 a. Explain the following terms with reference to a combustion process:
(i) Adaibatic flame temperature
(ii) Enthalpy of formation
(iii) Stoichiometric air
(iv) Enthalpy of combustion
(v) Combustion efficiency (10 Marks)
b. Methane (CH4) is burned with atmospheric air. The analysis of the products on a dry basis is
as follows: CO2 = 10%, 02 = 2.37%, CO = 0.53%, N2 = 87.10%.
(i) Determine the combustion equation
(ii) Calculate the air-fuel ratio
(iii) Percent theoretical air (10 Marks)
OR
6 a. Explain the following:
(i) Heat balance sheet
(ii) Morse test (10 Marks)
b. A single cylinder 4-stroke diesel engine give the following results while running on full
load, area of indicator diagram = 300 mm
2
, length of diagram = 40 mm. The spring
constant = 1 bar/nun, speed of the engine = 400 rpm, load on the brake = 370 N, spring
balance reading = 50 N, diameter of brake drum = 1.2 m, fuel consumption = 2.8 kg/hr,
calorific value fuel = 41800 kJ/kg, diameter of cylinder = 160 mm, stroke = 200 mm.
Calculate IP, BP, Brake mean effective pressure, brake specific fuel consumption, brake
thermal efficiency, indicator thermal efficiency. (10 Marks)
Module-4
7 a. With a neat sketch, describe clearly the working of a Bell-Coleman cycle. (06 Marks)
b. Write a brief note on properties of refrigerants. (04 Marks)
C. For food-storage purpose, a refrigeration plant of 10.5 TR is required at an evaporation
temperature of ?12?C and condenser temperature of 27?C. The refrigerant is ammonia. It is
sub-cooled by 6?C before entering the expansion valve. The vapour is 0.95 dry as it leaves
the evaporator coil. The compression is adiabatic using p-h chart. Calculate:
(i) Condition of vapour at outlet of the compressor
(ii) Condition of vapour at entrance to evaporator
(iii) CoP
(iv) Power required in KW.
Neglect throttling and clearance effect. (10 Marks)
OR
8 a. Define the following:
(i) Dry bulb temperature (ii) Dew point temperature
(iii) Relative humidity (iv) Specific humidity
(v) Degree of saturation (10 Marks)
b. An air-conditioning plant is to be designed for a small office for winter conditions. Outdoor
condition = 10?C DBT and 8?C WBT. Required indoor conditions = 20?C DBT and 60%
RH. Amount of air circulation = 0.3 m
3
/min/person seating capacity of the office = 50. The
required condition is achieved first by heating and then by adiabatic humidifying. Find the
followings:
(i) Heating capacity of the coil in KW and the surface temperature required if the bypass
factor of the coil is 0.32
?
(ii) The capacity of the humidifier. 4.-
- nr
(10 Marks)
2 of 3
FirstRanker.com - FirstRanker's Choice
USN
17ME43
Fourth Semester B.F.. Degree Examination, Dee.2019/Jan.2020
Applied Thermodynamics
Time: 3 hrs. Max. Marks: 100
Note: 1. Answer any FIVE full questions, choosing ONE full question from each module.
2. Use of thermodynamics data hand book is permitted.
c'
a.
Module-1
1 a. Show the compression ratio (r
e
) for maximum work should be per kg of air in an Otto cycle
L '
3
( \ 2(7-1)
between upper and lower limits of absolute temperature T3 and T3 is given r
(
.
1)
and also show that T
2
T
4
= (T, T
3
)
1 2
(10 Marks)
Compression ratio of diesel cycle is 14 and cut off ratio is 2.2 at beginning of cycle, air is
0.98 bar and 100?C. Find: (i) The temperature and pressure at salient points
(ii) Air standard efficiency. (10 Marks)
CS cci
:45
"
and the cycle efficiency. Assume the value of Cp = 1.005 kJ/kgK and y = 1.4. (10 Marks)
:... =
7::?:.
- i
Module-2 ,
a
3 a. Discuss with the help of T-S diagram the effect of Boiler pressure, condenser pressure and
,;- ..
o.
3-
= ?
super heat on the performance of a Rankine cycle. (10 Marks)
?
o.,
o cz
b. A 40 MW steam power plant working on Rankine cycle operator between boiler pressure of
C.) d'
e .9-
40 bar and condenser pressure of 0.1 bar. Steam leaves the boiler and enters the turbine at
400?C. The isentropic efficiency of steam turbine is 84%. Determine:
g i
i) Efficiency ii) Quality of exhaust iii) Steam flow rate in kg/hr.
. .
(10 Marks)
- -o
>,
= WI
?
?
a
w
E '>
o ?.. .).
8
?
Q.)
0
z
0
0.
= e' I
7
; F
-1)
OR
. .
?
T.
2 a. With a neat sketch, explain the working of Ramjet. (10 Marks)
E . 5
b.
In an open cycle gas turbine plant, air enters the compressor at I bar and 27?C. The pressure
r
A
0 1 after compression is 4 bar. The isentropic efficiencies of the turbine and the compressor are
(-)
(
L
)
8
85% and 80% respectively. Air fuel ratio is 80:1 calorific value of the fuel used is
? ?
? .0 42000 kJ/kg. Mass flow rate of air is 2.5 kg/sec. Determine the power output from the plant
to =
OR
4 a. A steam power plant operates on a theoretical reheat cycle. Steam at boiler outlet 150 bar,
550?C expands through the high pressure turbine. It is reheated at a constant pressure of 40
bar to 550?C and expands through the low pressure turbine to a condenser at 0.1 bar. Draw
T-S and h-s diagrams. Find:
(i) Quality of steam at turbine exhaust
(ii) Cycle efficiency
(iii) Steam rate in kg/KWh. (10 Marks)
b. With the help of neat diagram, explain the working of regenerative Rankine cycle and derive
the efficiency of the cycle. (10 Marks)
17N.
Module-3
5 a. Explain the following terms with reference to a combustion process:
(i) Adaibatic flame temperature
(ii) Enthalpy of formation
(iii) Stoichiometric air
(iv) Enthalpy of combustion
(v) Combustion efficiency (10 Marks)
b. Methane (CH4) is burned with atmospheric air. The analysis of the products on a dry basis is
as follows: CO2 = 10%, 02 = 2.37%, CO = 0.53%, N2 = 87.10%.
(i) Determine the combustion equation
(ii) Calculate the air-fuel ratio
(iii) Percent theoretical air (10 Marks)
OR
6 a. Explain the following:
(i) Heat balance sheet
(ii) Morse test (10 Marks)
b. A single cylinder 4-stroke diesel engine give the following results while running on full
load, area of indicator diagram = 300 mm
2
, length of diagram = 40 mm. The spring
constant = 1 bar/nun, speed of the engine = 400 rpm, load on the brake = 370 N, spring
balance reading = 50 N, diameter of brake drum = 1.2 m, fuel consumption = 2.8 kg/hr,
calorific value fuel = 41800 kJ/kg, diameter of cylinder = 160 mm, stroke = 200 mm.
Calculate IP, BP, Brake mean effective pressure, brake specific fuel consumption, brake
thermal efficiency, indicator thermal efficiency. (10 Marks)
Module-4
7 a. With a neat sketch, describe clearly the working of a Bell-Coleman cycle. (06 Marks)
b. Write a brief note on properties of refrigerants. (04 Marks)
C. For food-storage purpose, a refrigeration plant of 10.5 TR is required at an evaporation
temperature of ?12?C and condenser temperature of 27?C. The refrigerant is ammonia. It is
sub-cooled by 6?C before entering the expansion valve. The vapour is 0.95 dry as it leaves
the evaporator coil. The compression is adiabatic using p-h chart. Calculate:
(i) Condition of vapour at outlet of the compressor
(ii) Condition of vapour at entrance to evaporator
(iii) CoP
(iv) Power required in KW.
Neglect throttling and clearance effect. (10 Marks)
OR
8 a. Define the following:
(i) Dry bulb temperature (ii) Dew point temperature
(iii) Relative humidity (iv) Specific humidity
(v) Degree of saturation (10 Marks)
b. An air-conditioning plant is to be designed for a small office for winter conditions. Outdoor
condition = 10?C DBT and 8?C WBT. Required indoor conditions = 20?C DBT and 60%
RH. Amount of air circulation = 0.3 m
3
/min/person seating capacity of the office = 50. The
required condition is achieved first by heating and then by adiabatic humidifying. Find the
followings:
(i) Heating capacity of the coil in KW and the surface temperature required if the bypass
factor of the coil is 0.32
?
(ii) The capacity of the humidifier. 4.-
- nr
(10 Marks)
2 of 3
17ME43
Module-5
9 a. Define the following with respect to a compressor:
i) Isothermal efficiency ii) Adiabatic efficiency iii) Mechanical efficiency
iv) Overall efficiency v) Volumetric efficiency (10 Marks)
b. An air compressor takes in air at 1 bar and 20?C and compresses the same according to the
law PV'
.-
= C. It is the delivered to a receiver at a constant pressure of 10 bar.
Determine:
(i) Temperature at the end of compression
(ii) Work done and heat transferred during compression per kg of air R ? 0.287 kJ/kgK.
(10 Marks)
OR
10 a. Prove the maximum flow rate of steam per unit area through a nozzle occurs when the ratio
- I
of pressure at throat to the inlet pressure is equal to P
2
/ P, = where n is polytropic
n +1)
n
index of expansion. (10 Marks)
b. Dry saturated steam at a pressure of 11 bar enters a convergent divergent nozzle and leaves
at a pressure of 2 bar. If the flow is adiabatic frictionless. Determine: (i) Exit velocity of
steam (ii) Ratio of cross-section area at exit and at throat. Assume the index of adiabatic
expansion to be 1.135. (10 Marks)
3 of 3
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This post was last modified on 02 March 2020