Hall Ticket No Question Paper Code: AME003
INSTITUTE OF AERONAUTICAL ENGINEERING
(Autonomous)
Four Year B.Tech III Semester End Examinations (Supplementary) January, 2019
Regulation: IARE R16
THERMODYNAMICS
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. Draw an isothermal process on p-V and T-s diagram and derive the equation for work transfer.
Work and heat are not properties. Justify.
A gas undergoes a thermodynamic cycle consisting of the following processes:
Process Constant pressure p 1.4 bar, V1 0.028 m3, 10.5kJ
Process Compression with pV constant, U3 U2
Process Constant volume, U1 U3 26.4 kJ. There are no significant changes in KE
and PE.
(i)Sketch the cycle on a p-V diagram
(ii)Calculate the net work for the cycle in kJ.
(iii)Calculate the heat transfer for process 1-2.
Show that cycle P
cycleQ P
cycle W
2. What is meant by equilibrium? Explain types of equilibrium. For a system to be in thermodynamic
equilibrium do the temperature and pressure have to be the same every where? Explain.

Air flows steadily at the rate of 0.4 kg/s through an air compressor,entering at 6m/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. Kelvin-Planck Clausius statements are equivalent to one another. Justify in words. Why is
the second law of thermodynamics referred to as the law of degradation of energy?
A reversible cyclic heat engine operates between the maximum and minimum temperatures of
6710C and 600C respectively. It drives a heat pump which uses river water at 4:4oC to heat a block
of flats in which the temperature is to be maintained at 21:1oC. Assuming that a temperature
difference of 11:1oC exists between the working fluid and the river water, on the one hand, and
the required room temperature on the other, and find the heat input to the engine per unit heat
output from the heat pump. Why is direct heating thermodynamically more wasteful?
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4. Derive Maxwell equation. Elaborate the relationship between s in terms of partial
derivatives.
1 kg of ice at 5°C is exposed to the atmosphere which is at 25°C. The ice melts and comes into
thermal equilibrium. Determine the entropy increase of the universe.
UNIT III
5. Draw the phase equilibrium diagram for a pure substance on p-T and T-s coordinates with
relevant constant property lines. Why does the fusion line for water have negative slope?
Steam initially at 0.3 MPa, 250°C is cooled at constant volume.
At what temperature will the steam become saturated vapour?
What is the quality at 80°C?
What is the heat transferred per kg of steam in cooling from 250°C to 80°C?
6. Explain the procedure adopted in steam calorimetry? Why cannot a throttling calorimeter
measure the quality, if the steam is wet? Explain how is the quality been measured?
1 kg of water fills a 150 liter rigid container at an initial pressure of 2 MPa. The container is
then cooled to 40oC. Determine the initial temperature and final pressure of the water.
UNIT IV
7. Define Mass fraction and Mole fraction and deduce the relation between them. Explain Dalton's
law of partial pressure?
A vessel contains at 1 bar and 20°C a mixture of 1 mole of CO2 and 4 moles of air.
Calculate for the mixture The masses of CO2, O2 and N2, and the total mass The
percentage carbon content by mass; The apparent molecular weight and the gas constant for
the mixture; The specific volume of the mixture.
The volumetric analysis of air can be taken as 21% oxygen and 79% nitrogen.
8. Define the terms dry bulb temperature(dbt), wet bulb temperature(wbt), dew point temperature,
relative humidity, specific humidity, degree of saturation
Atmospheric air at 1.0132 bar has a dbt of 32°C and a wbt of 26°C. Compare the partial
pressure of water vapour, the specific humidity, the dew point temperature, the relative
humidity, the degree of saturation the density of the air in the mixture, density of
vapour in the mixture
UNIT V
9. Define compression ratio. What is the range for SI engines and the CI engines? What factors
limit the compression ratio in each type of engine?
Draw p-V and T-s diagram for Diesel cycle. A diesel engine has a compression ratio of 15 and
heat addition at constant pressure takes place at of stroke. Find the air standard efficiency
of the engine. Take
for air as 1.4.
10. Define air standard efficiency of an Otto cycle and show that the efficiency of Otto cycle is lower
than that of Carnot cycle.
An engine of 250mm bore and 375mm stroke works on Otto cycle. The clearance volume is
0.00263m3 . The initial pressure and temperature are 1bar and 50oC. The maximum pressure is
limited to 25 bars. Find the air standard efficiency and the mean effective pressure of the cycle?
Assume ideal conditions?