UNIVERSITY INSTITUTE OF ENGINEERING
Aerospace Engineering
PROGRAM CODE: AS201/AS202
Subject Name : AERO THERMODYNAMICS Subject Code : 24AST-202
ASSIGNMENT – 1
Submission Last Date: 30-08-2025
Sr. Question CO Mapping
No.
1. A certain quantity of air has volume of 0.028 m3 at a pressure of
1.25 bar and 25oC. It is compressed to a volume of 0.0042 m3
according to a law pv1.3 = C. Find the final temperature and work
CO4
done during compression. Also determine the reduction in
pressure at constant volume to bring air back to its original
volume.
2. A gas initially at 630 K expands until its volume is 5.2 times the
initial volume according to pvn = C. if initial and final pressures
are observed to be 8.5 bar and 1 bar. Determine (i) index of CO5
expansion (ii) work done per kg of gas (iii) heat exchange per kg
of gas. Assume Cv = 0.712 kJ/kg-K and γ = 1.4.
3. A certain water heater operates under steady flow conditions
receiving 4.2kg/s of water at 75oC temperature, enthalpy
313.93kJ/kg. The water is heated by mixing with steam which is
CO4
supplied to the heater at 100.2oC and enthalpy 2676kJ/kg. The
mixture leaves the heater as liquid water at 100oC and enthalpy
419kJ/kg. Compute steam to be supplied for the heater per hour.
4 2 kg of gas at pressure of 1.5 bar occupies a volume of 2.5 m3. If
this gas compresses isothermally to 1/3 times of the initial CO4
volume. Find the initial temperature, work done and heat transfer.
5 A certain quantity of gas is heated at constant pressure from 35oC
to 185oC. Estimate the amount of heat transferred, ideal work
CO5
done, change in internal energy, when initial volume of gas is 0.6
m^3.
6 Derive relation for maximum work obtained from two finite
CO4
bodies at T1 & T2, where T1 >T2.
7 The interior light of refrigerator is provided by incandescent
lamps whose switches are actuated by opening of refrigerator
door. Consider a refrigerator whose 40 W light bulb remains on
continuously as results of malfunction of the switch. If the
CO4
refrigerator has a coefficient of performance of 1.3 and the cost of
electricity is rupees 8 per kWh. Determine the increase in the
energy consumption of the refrigerator and its cost per year if
switch is not fixed.
8 An insulated 5 m3 rigid tank contains air at 500 kPa and 57oC. A
CO5
valve connected to the tank is now opened and air is allowed to
UNIVERSITY INSTITUTE OF ENGINEERING
Aerospace Engineering
PROGRAM CODE: AS201/AS202
Subject Name : AERO THERMODYNAMICS Subject Code : 24AST-202
escape until the pressure inside drops to 200 kPa. The air
temperature during this process maintained constant by an electric
resistance heater placed in the tank. Determine (i) the energy
supplied during this process (ii) the total entropy change.
9 1 m3 of air is heated reversibly at constant pressure from 15oC to
3000oC and then cooled reversibly at constant volume back to the
initial temperature. The initial pressure is1.03 bar. Calculate the CO5
net heat flow and overall change of entropy. Sketch the process
on T-s diagram.
10 Two Carnot refrigerators „A‟ and „B‟ operate in series. The
refrigerator „A‟ absorbs energy at the rate of 1 kJ/s from a body at
300 K and rejects energy as heat to a body at „T‟. The refrigerator
„B‟ absorbs same quantity of energy which is rejected by the
refrigerator „A‟ from the body at „T‟ and rejects energy as heat to CO5
a body at 1000 K. If both refrigerators have the same COP,
calculate: (i) the temperature „T‟ of the body (ii) the COP of
refrigerator and (iii) the rate at which energy is rejected as heat to
the body at 1000 K.
11 Two Carnot engines work in series between the source and sink
temperature of 500 K and 300 K. If both engines develop equal CO4
power, determine the intermediate temperature.
12 Two vessels A & B, each of volume 3 m3 may be connected by a
tube of negligible volume. Vessel „A‟ contains air at 0.7 MPa,
95oC, while vessel „B‟ contains air at 0.35 MPa, 250oC. Find
CO5
the change in entropy when „A‟ is connected „B‟ by working from
the first principle and assuming the mixing tube to be complete
and adiabatic.
13 0.4 m3 of air at 5 bar and 130oC is contained in a system. A
reversible adiabatic expansion takes place till the pressure falls to
1.02 bar. The gas is the heated at constant pressure till enthalpy
increased by 72.5 kJ. Calculate (i) work done (ii) the index of CO4
expansion, if the above processes are replaced by a single
reversible polytropic process giving the same work between the
same initial and final states.
14 A mass of 1.5 kg of air is compressed in Q-S process from 0.1
MPa to 0.7 MPa for which pv = C. The initial density of air is CO4
1.16 kg/m3. Find the work done by the piston to compress the air.
15 Three grams of nitrogen gas at 6 atm and 160 is expanded
CO5
adiabatically to double its initial volume and the compressed
UNIVERSITY INSTITUTE OF ENGINEERING
Aerospace Engineering
PROGRAM CODE: AS201/AS202
Subject Name : AERO THERMODYNAMICS Subject Code : 24AST-202
again at constant volume to its initial state. Calculate the work
done on the gas. Draw p – v diagram for the process. Specific
heat ratio of nitrogen is 1.4.
16 In an air compressor, air flows steadily at the rate of 0.5 kg/s. At
entry to the compressor, air has a pressure of 105kPa and specific
volume of 0.86 m3/kg and at exit of compressor those
corresponding values are 705 kPa and 0.16 m3/kg. Neglect
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kinetic energy and potential energy change. The internal energy
of air leaving the compressor is 95 kJ/kg greater than of air
entering. The cooling water in the compressor absorbs 60kJ/s of
heat from the air. Find power required to drive the compressor.
