Hall Ticket No Question Paper Code: AME003
INSTITUTE OF AERONAUTICAL ENGINEERING
(Autonomous)
B.Tech III Semester End Examinations (Regular) December, 2017
Regulation: IARE R16
THERMODYNAMICS
(Mechanical Engineering)
Time: 3 Hours Max Marks: 70
Answer ONE Question from each Unit
All Questions Carry Equal Marks
All parts of the question must be answered in one place only
UNIT I
1. Derive an expression for the non-flow displacement work done during adiabatic process given by
PV
where
Cp/Cv
A closed system undergoes two processes one after the other-constant pressure process at pressure
of 5 bar from initial volume of 0.03 m3 to 0.09 m3 it is followed by polytropic expansion. PV
from 0.09 m3 volume to 0.02 m3 final volume find
i. Final pressure after expansion
ii. Work done during each process and net work done
2. Explain Joules experiment with reference to PMM1.
Air flows steadily at the rate of 0.4 kg/s through an air compressor, entering at 6 m/s with a
pressure of 1 bar and a specific volume of 0.85 m3/kg, and leaving at 4.5 m/s with a pressure of
6.9 bar and a specific volume of 0.16 m3/kg. The internal energy of the air leaving is 88 kJ/kg
greater than that of the air entering. Cooling water in a jacket surrounding the cylinder absorbs
heat from the air at the rate of 59 W. Calculate the power required to drive the compressor and
the inlet and outlet cross-sectional areas.
UNIT II
3. Distinguish between heat engine and heat pump.
Two reversible heat engines A and B are arranged in series, A rejecting heat directly to B. Engine
A receives 200 kJ at a temperature of 421C from a hot source, while engine B is in communication
with a cold sink at a temperature of 4.4C. If the work output of A is twice that of find
i. The intermediate temperature between A and B
ii. The efficiency of each engine
iii. The heat rejected to the cold sink
4. What is Carnot's cycle? Explain in detail with relevant sketches and processes.
Two kg of water at 80C are mixed adiabatically with 3kg of water at 30C in a constant pressure
process of 1 atmosphere. Find the increase in entropy of the total mass of water due to mixing
process.
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UNIT III
5. Draw the phase equilibrium diagram for pure substance on h-s plot with relevant constant property
lines and why the isobars lines are diverges from one another?
A vessel of volume 0.04 m3 contains a mixture of saturated water and saturated steam at a
temperature of 250C. The mass of the liquid present is 9 kg. Find pressure, the specific volume,
the enthalpy, the entropy.
6. Derive an expression for the Vander Walls constants and in terms of critical properties.

1 kg of CO2 has a volume of 0.86 m3 at 120C. Compute the pressure using
Ideal gas equation
ii) Vander Wall's Equation
Take Vander Wall's constant for CO2, a 365.6 kNm4/(kg mole)2 and b 0.0423 m3/(kg mole)
UNIT IV
7. Define mole fraction and mass fraction.
0.5 kg of helium and 0.5 kg of nitrogen are mixed at 20°C and at a total pressure of 100 kPa.
Find
the mole fraction of each constituent
Equivalent molecular weight of the mixture
the equivalent gas constant of mixture
the partial pressures and volumes
Cp and Cv of the mixture.
8. Explain
Dew point temperature
Degree of saturation
Adiabatic saturation process
An air water vapour mixture enters an adiabatic saturator at 30C and leaves at which is
the adiabatic saturation temperature. The pressure remains constant at 100kPa. Determine the
relative humidity and the humidity ratio of the inlet mixture.
UNIT V
9. For the same compression ratio and heat rejection, which cycle is most efficient; Otto, diesel or
dual? Explain with P-V and T-S diagrams.
An ideal diesel cycle with air as the working fluid has a compression ratio of 18 and a cut-off
ratio of 2. At the beginning of compression, the air is at 100kPa, 27C and 1917 cm3. Determine
the pressure and temperature of air at each point
the net work and thermal efficiency
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10. Derive air standard efficiency of Brayton cycle with P-V and T-S diagram
An air refrigeration open system operating between 1 mpa and 100 kpa is required to produce
cooling effect of 2000 kJ/min. the temperature of air leaving the cold chamber is and
at leaving the cooler is 30C. Neglecting losses and clearance in the compressor and expander
determine
Mass of air circulated per hour
ii) Compressor work, expander work, cycle work
iii) Coefficient of performance and power required to run the machine