PRIYADARSHINI COLLEGE OF ENGINEERING, NAGPUR

Department: Aeronautical Engineering

Semester: III
Subject: Aero- Thermodynamic

Question Bank

Unit 1 and 2

1) A tank containing liquid is mixed by paddle wheel. The work input to the paddle is 5090kJ.
The heat transfer from tank is 1500 kJ. Considering tank & fluid as system. Determine the
change in i9nternal energy.
2) A closed system undergoes a thermodynamics cycle consist of four spate and distinct
process. The following data gives work and heat transfer for each process. Show that data
is consistent with first law & determine net work output in kW. Change in internal energy
in each process.

Process Heat Transfer (kJ/min) Work Transfer in (kJ/min)

1-2 Nil -200000
2-3 20000 Nil
3-4 -2000 3400
4-1 -6000 -2000

3) A non-flow quasi static process occurs in which P= (-3V + 16) bar where V is in volume
in m3. Determine i the work done when V change from 2 m3 to 6 m3
4) The pressure and volume relation during non-flow reversible process is given by
8
P = (V 2 + ) bar. The volume changes V1 = 6m3 to V2 = 2m3 .Calculate the work done,
V
the heat rejected during process is 200 KJ. Determine the change in internal energy.

5) A fluid system undergoes a non-flow frictionless process following the pressure volume
5
relationship as P = ( + 1.5) , Where P is in Bar and V is in m3. During the process, the
V
volume changes from 0.15m3 to 0.05 m3 and the system rejects 45kJ of heat. Determine the
change in internal energy and enthalpy.
100
6) A certain non-flow process pressure and specific volume are related by P = ( −V 2 ) ,
V
where P in bar, V in m3/kg. Find the work done per Kg in moving the piston from an initial
volume of 0.01 m3/kg to 0.6 m3/kg.

7) In a system executing a non-flow process the work and heat for degree change of
temperature are given by dw/dT=200 J/ 0C & dQ/dT=160 J/ 0C. What will be the change
of internal energy of system when its temperature changes from 55 0C to 95 0C?

8) 0.25Kg of air at pressure of 140 KN/m2 occupies 0.15 m3 and from this condition it is
compressed to 1.4 MN/m2 according to the law PV 1.25 = constant . Determine (i) the

Mr. S. S. Giri, Aeronautical Engg. Dpt, PCE, Nagpur

 change of internal energy of the air (ii) the work done on or by the air (iii) the heat received
or rejected by the air. Take CP= 1.005 kJ/Kg-k, Cv=0.718 kJ/Kg-k.

9) A cylinder contains 0.45m3 of gas at 1 bar and 800C. the gas is compressed to volume of
0.13m3, the final pressure being 5 bar. Determine (i) the mass of gas (ii) The volume of
index “n” for compression.  = 1.4, R = 294.2 J / kg 0C

10) 0.2 kg of air with P1= 1.5 bar and T1= 300K is compressed to a pressure of 15 bar, according
to the law PV 1.25 = constant .Determine (i) initial and final parameters of the air (ii) work
done on or by the air (iii) heat flow to or from the air.  = 1.4, R = 294.2 J / kg 0C

11) A gas undergoes a thermodynamic cycle consisting of the following process.

i) Process 1-2: constant pressure

P = 1.4bar ;V1 = 0.028m3 ;W1− 2 = 10.5kJ
ii) Process 2-3: Compression with
PV = Constant; U 3 =U 2
(iii) process 3-1: Contant volume
U1 − U 3 = −26.4kJ
Ther are no significant changes in KE and PE (a) sketch the cycle on P-V diagram (b)
Calculate the net-work for the cycle in kJ(c) Calculate the heat transfer for process 1-2.

12) A fluid at pressure of 3 bar and specific volume of 0.18 m3/kg is compressed in cylinder
C
behind a piston, the fluid expands to a pressure of 0.6 bar according to the law P = 2 ,
V
where C is constant. Calculate the work done by the fluid on the piston.

13) A gas in a piston cylinder assembly undergoes an expansion process for which the relation
between pressure and volume is given by PV n = constant . The initial pressure is 3 bar and
the initial volume is 0.1m3 and final volume is 0.2m3. Determine the work for the process
in kJ if (I) n=1.5 (ii) n=1 and (iii) n=0.

14) A gas having a volume of 0.05m3 and pressure of 6.9 bar expands reversibly in cylinder
behind a piston according to the law PV n = constant until the volume is 0.08m3. Calculate
the work done by the gas. Also sketch process on P-V diagram.

15) During a reversible constant Pressure non-flow process at P=1.6 bar, the properties of the
system changed from V1=0.3m3/Kg, T1=200C to V2= 0.55m3/Kg, T2=2600C. The specific
heat of the fluid is given by C p = 1.5 +
75 
 kJ / Kg C , Where T is in 0C. Determine
0

 T + 45 
(i) Heat added per Kg (ii) Work done per Kg (iii) Change in internal energy per Kg (iv)
Change in enthalpy per Kg.

16) A cylinder contains 0.5m3 of gas at pressure of 1 x 105 N/m2 and temperature of 900C. the
gas is compressed to a volume of 0.125m3. the final pressure being 6 x 105 N/m2. Determine
(i) mas of gas (ii) volume of index “n” for compression (iii) increasing internal energy of
gas (iv) Heat received or rejected by the gas during compression  = 1.4, R = 294.2 J / kg 0C

Mr. S. S. Giri, Aeronautical Engg. Dpt, PCE, Nagpur

 17) A gas in piston-cylinder assembly undergoes an expansion process for which the relation
between pressure and volume is given PV n = constant . The initial pressure is 0.5MPa, the
initial volume is 0.15m3 and the final volume is 0.25m3, determine the work transfer for
the process in kJ if (i)n=0 (ii) n=1 (iii)n=1.5. Draw the process on P-V diagram.
8
18) A non-flow reversible process follows the law P = (V 2 + ) where P is in bar and V is in
V
m3. Find the work done during the process when the volume change from 3 m3 to1 m3
19) The internal energy of a certain system is function of temperature only and is given by
u = (25 + 0.25T ) Where T is temperature in 0C when this executes a certain process, the
dw
work done per degree temperature change is given by = 350 T joule. Find the heat
dT
transfer when the temperature of the system changes from 1000C to 2600C.

Mr. S. S. Giri, Aeronautical Engg. Dpt, PCE, Nagpur

Unit -III
1) A machine operating as a heat pump extracts heat from the surrounding atmosphere is
driven by a 7.5 kW motor and supplies 2 x 105 kJ/hr heat to a house needed for its heating
in winter. Find coefficient of performance for the heat pump. How this COP will be
affected if the objective of the same machine is to cool the house in summer requiring 2 x
105 kJ/hr of heat rejection?
2) A reversible heat engine operates between two reservoirs at temperature of 875K and 310K
drives a reversible refrigerator which operates between reservoir at temperature of 310 K
and 255k. The engine revives 2000 kJ of heat and the net work output from the arrangement
equal to 350kJ. Calculate the cooling effect.
3) Two Carnot engines work in series between source and sink temperature of 550k and
350k.If both engines develop equal power determine the intermediate temperature.
4) Three Carnot heat engines are arranged in series. The first engine takes 4000kJ of heat from
a source at 2000k and delivers 1800kJ of work; the second and the third engines delivers
1200kJ and 500kJ of work respectively. Calculate the exhaust temperature of the second
and third Carnot engine.
5) Domestic food refrigeration maintains a temperature of -120C. The ambient air temperature
is 350C. if heat leaks into the freezer at the continuous rate of 2kJ/s, Determine the least
power necessary to pump this heat out continuously.
6) One kg of ice at -400C is exposed to the atmosphere which is at 200C. the ice melts and
comes into equilibrium with atmosphere. Determine the entropy increase of the universe.
For ice take Cp=2.09kJ/Kg-k and latent heat of fusion=333kJ/Kg.
7) Find the COP and heat transfer rate the condenser of a refrigerator in kJ/hr which has a
refrigeration capacity 12000kJ/hr. when power input is 0.75kW.
8) A fish freezing plant requiresn50 tons of refrigeration. The freezing temperature is -400C
while the ambient temperature is 350C. If the performance of the plant is 15% of the
theoretical reversed Carnot cycle working Whitin the same temperature limits, Calculate
the power required.
9) A household refrigerator is maintained at a temperature of 50C, every time the door is
opened, warm material is placed inside, introducing an average of 420kJ, but making only
a small change in the temperature of the refrigerator. The door is opened 20 times a day
and the refrigerator operates at 15% of ideal COP. The cost of work is Rs. 2.5 per Kwh.
What is the monthly bill for the refrigerator? The atmosphere temperature is at 300C.
10) A cyclic engine operates between a source temperature of 8000C and sink temperature of
300C. What is the least rate of heat rejection per Kw net output of the engine?

Mr. S. S. Giri, Aeronautical Engg. Dpt, PCE, Nagpur

Unit-IV
1) Find the dryness fraction, specific volume and internal energy of steam at 7 bar and
enthalpy 2550kJ/kg.
2) Find the internal energy of 1kg of steam at 20 bar when (i) it is superheated at
temperature 4000C (ii) it is wet with dryness fraction 0.9 Take specific heat 2.3kJ/kg-K.
3) Find the internal energy of one kg of steam at 14bar under the following conditions:
i) When the steam is 0.85 dry.
ii) When steam is dry and saturated.
iii) When the temperature of steam is 3000C. Take CPsup = 2.25kJ/kg-K.
4) Determine enthalpy, volume and density of one kg of steam at a pressure of 5 MN/m3:
(i) When the steam is 90% dry and (ii) When temperature of the steam is 3000C.
5) Steam enters an engine at a pressure of 12bar with 2000C of superheat. It is exhausted
at a pressure of 0.15bar and 0.95 dry. Find the drop in the enthalpy of the steam.
6) Calculate the internal energy per kg of superheated steam at a pressure of 10 bar and a
temperature of 3000C. If the steam is expanded to 1.4bar and dryness fraction 0.8, find
change in the internal energy. Take CPsup = 2.1kJ/kg-K.
7) One kg of steam at a pressure of 17.5bar and dryness 0.95 is heated at constant pressure,
until it is completely dry. Determine: (i) The increase in volume (ii) The quality of heat
supplied and (iii) The change in entropy.
8) Steam at 20bar and 250 0C expands through a nozzle isotopically to a pressure of
1bar. Determine the velocity of steam at exit. Neglect approach velocity.
9) Two boilers one with superheater and other without superheater are delivering equal
quantities of steam into a common main. The pressure in the boilers is 20bar. The
temperature o f st e a m f r o m a boi l er w i t h a s up er h e at er i s 3500C and temperature
of the steam in the main is 2500C. Determine quality of steam supplied by the other
boiler. Take C Psup = 2.25kJ/kgK.
10) A sample of steam from a boiler drum at 3 Mpa is throttled to the pressure of 1 bar, 200C.
Explain the procedure to measure quality of the sample taken from the boiler and give
its value.
11) 1 Kg of steam at 8 bar ,250 0C expands Polytropically to 2 bar accordingly to PV 1.3=
constant. Determine the quality of steam at final state, heat transfer and change in
entropy during the expansion process.
12) In a throttling calorimeter, the steam is admitted at 10 bar, it is throttled to atmospheric
pressure and 1100C. Determine the dryness fraction of steam. Assume the specific heat of
superheated steam as 2.2 kJ/Kg-K.
13) Find the internal energy of 1 Kg of steam at pressure of 10 bar when the condition of
steam is (I) wet with dryness fraction of 0.85 (ii) Dry and saturated (iii) superheated with
degree of superheat being 50 0C Cpsup=2.01 KJ/Kg-K.
14) Steam enters an engine at pressure of 10 bar absolute and 400 0C. it is exhausted at 0.2
bar. The steam at exhaust is 0.9 dry. Find (1) Drop in Enthalpy (2) Change in Entropy.

Mr. S. S. Giri, Aeronautical Engg. Dpt, PCE, Nagpur

Unit-5
1) In air standard Otto cycle that has heat addition of 2800 kJ/kg of air a compression ratio
of 8, and a pressure and temperature at the beginning of compression process of 1bar,
300K. Determine – (a) The maximum pressure and temperature in cycle b) the thermal
efficiency c) Mean effective pressure For air: CP = 1.005 kJ/kg-K,C V = 0.718 kJ/kg-K,
R = 287 J/kg-K.
2) Four stroke engines working on the Otto cycle has a swept volume of 0.1m 3. The
compression ratio is 7. The condition at the start of the cycle: Pressure 0.1MPa and
temperature 900C. The heat addition is 100kJ/cycle. Find the ideal efficiency, mean
effective pressure and temperature at key points in the cycle. Assume air as working
substance and γ = 1.4
3) In an air- standard Diesel cycle, the compression ratio is 16, and at the beginning of
isentropic compression, the temperature is 150C and the pressure is 0.1MPa. Heat is
added until the temperature at the end of the constant p r e s s u r e process is 14800C.
Calculate: (i) The cut-off ratio (ii) The heat supplied per kg of air (iii) The cycle
efficiency (iv)The mean effective pressure.
4) The diesel cycle with a compression ratio of 16 is having lowest pressure and lowest
temperature in the cycle as 1bar and 300K. The heat added per kg to the engine is 2500kJ/kg.
Calculate (a) Thermal efficiency of the cycle b) Mean effective pressure.
5) In a diesel cycle the volume ratios of the adiabatic expansion and compression are 7.5:1 and
15:1 respectively. The pressure and temperature at the beginning of the compression are 98
kN/m2 and 440C respectively. The pressure at the end of the adiabatic expansion is
258kN/m2. Determine:(i) The maximum temperature attained during the cycle (ii) the
thermal efficiency of the cycle Take γ = 1.4
6) An ideal diesel cycle operates on 1kg of standard air with initial pressure of 1bar and
temperature of 350C. The pressure at the end of compression is 33bar and cut off 6% of
stroke. Determine (i) Compression ratio (ii) Heat supplied (iii) Heat rejected, Take CP =
1.005 kJ/kg-K , CV = 0.718 kJ/kg-K.
7) A gas turbine works on Brayton cycle. The initial condition of the air is 1bar and 250C. The
maximum pressure and temperature are 3bar and 6600C respectively. Calculate: (i) Cycle
efficiency, (ii)Heat supplied and heat rejected per kg of air, (iii) Work done per kg of air
(iv) Exhaust temperature.
8) In an air standard Otto Cycle the compression ratio is 7 and the compression begins at 350C
and 0.1 MPa. The maximum temperature of the cycle is 11000C. Find: (i) temperature and
pressure at the cardinal points of the cycle. (ii) Heat supplied per Kg of air. (iii) Work done
per Kg of air. (iv)Cycle efficiency. (v) Mean effective pressure.
9) The minimum pressure and temperature in an Otto Cycle are 100Kpa and 270C. The amount
of the heat added to the air per Cycle is 1500KJ/kg: (i) determine the pressure and
temperature at all points of the air standard Otto Cycle. (ii) Also calculate the specific work
and thermal efficiency of the cycle for a compression ratio of 8:1. Take for air CV =
0.72kJ/kg-K. γ=1.4
10) In engine working on otto cycle is supplied with air at 1 bar and 250C.The compression ratio
is 9:1 heat supplied is 2000KJ/Kg. Calculate (i) Pressure and temperature at all salient points
(ii) The cycle efficiency and (iii) The mean effective pressure
11) The compression ratio in an air standard otto cycle is 8. At the beginning of compression
process the pressure is 1 bar and the temperature is 300K.The heat transfer to the air per
cycle is 1900 KJ/Kg of air. Calculate (i) Thermal Efficiency (ii) Mean effective pressure
12) In engine working on otto cycle has an air standard cycle efficiency of 56% and rejects 544
KJ/Kg of air. The pressure and temperature of air at the beginning of compression are 1 bar
and 600C respectively. Determine (i) the compression ratio of the engine (ii) work done per
Kg of air (iii) The pressure and temperature at the end of compression (iv)the maximum
pressure in the cycle.

Mr. S. S. Giri, Aeronautical Engg. Dpt, PCE, Nagpur

 13) In an air- standard Diesel cycle has compression ratio is 14. The pressure at beginning
of compression stroke is 1 bar and temperature is 300K.The maximum cycle temperature
is 2500K. Determine the cut-off ratio and thermal efficiency of the cycle.
14) Air standard Diesel cycle has a compression ratio of 18 and the heat transfer to the working
fluid per cycle is 1800KJ/Kg. At the beginning of the compression stroke the pressure is
1 bar and the temperature is 300K.Calculate (i) Thermal efficiency (ii) mean effective
pressure.
15) An engine working on the otto cycle is supplied with air at 0.1 Mpa, 35 0C. The
compression ratio is 8. Heat supplied is 2100KJ/Kg. Calculate the maximum pressure and
temperature of the cycle, The cycle efficiency and mean effective pressure .
SFEE
1) A steam turbine receives 600 kg of steam per hour at 25 bar, 450 0C with a velocity of 100
m/s and at elevation of 5 m. Heat transfer from the turbine to the surrounding is 3762
kJ/Hour. Steam level the turbine dry saturated and 1.2bar with a velocity of 150 m/s and at
an elevation of 2m. Determine the power developed by the turbine.
2) In an air compressor, Air flows steadily at the rate of 15kg per minute. The air enters the
compressor at 5m/s with a pressure of 1 bar and a specific volume of 0.5m3/kg. It leaves
the compressor at 7.5 m/s with pressure of 7 bar and a specific volume of 0.15m3/kg. The
internal energy of the air leaving the compressor is 165 kJ/kg greater than that of the air
entering. The cooling water in the compressor jacket absorb heat from the air at the rate of
125 kJ/s. find: (i) power required to drive the compressor. (ii) ratio of the inlet pipe diameter
to outlet pipe diameter.
3) At the inlet to a certain nozzle the enthalpy of fluid passing is 2800 kJ/Kg and the velocity
is 50m/s. at the discharge end the enthalpy is 2600kJ/kg. The nozzle is horizontal and there
is negligible heat loss from it. (i) Find the velocity of exit of the nozzle. (ii) If the inlet area
is 900 cm2 and specific volume at inlet is 0.187m3/kg. Find the mass flow rate. (iii) If the
specific volume at nozzle exit is 0.498 m3/kg. Find the exit area of the nozzle.
4) A centrifugal air compressor used in gas turbine receives air at 100Kpa and 300K and it
discharge air at 400 Kpa and 500K. The velocity air leaving the compressor is 100 m/s.
Neglecting the velocity of air at the entry of the compress, Determine the power required
to drive the compressor if the mass flow rate is Kg/s. Assume that there is no heat transfer
from compressor to the surrounding. Take Cp for air 1 KJ/Kg K.
5) Steam with an enthalpy of 3000 KJ/Kg and specific volume of 0.187 m3/Kg enters a steam nozzle
and leaves with 2762 KJ/Kg of enthalpy and 0.498 m3/Kg specific volume. The inlet velocity of
steam is 60 m/s and inlet area is 0.1m2. Find out velocity of steam at exit of the nozzle, steam mass
flow rate and exit area.

Mr. S. S. Giri, Aeronautical Engg. Dpt, PCE, Nagpur