JNTU, B.Tech ,I-Semester
(Mechanical Engineering and Automobile Engineering)
1. (a) Explain thermodynamic system, surroundings and universe, illustrate the same
(b) Distinguish between closed system, open system and isolated system with
suitable examples. [8+8]
2. In a vessel 10 kg of oxygen is heated in a reversible, non flow, constant volume
process so that the pressure of oxygen is increased two times that of the initial value. The initial temperature is 20oC. Calculate
(a) the final temperature,
(b) the change in internal energy,
(c) the change in enthalpy and
(d) the heat transfer. Take R = 0.259 kj / kg K and Cv = 0.652 kj / kg K for oxygen. 
3. (a) Prove: perpetual motion machine of the second kind is impossible.
(b) Three cubic metres of air at a pressure of 1bar and a temperature of 200 C is compressed reversible and adiabatically to 4.5 bar. The same mass is then expanded is othermally to the original volume. Calculate the final pressure of the air, work done and the total entropy change. For air Cp= 1.005 kJ/kg.K and R = 0.287J/kg.K (10) [6+10]
4. (a) A pressure vessel has a volume of 1m3 and contains air at 1.4 MPa, 1750C. The
air is cooled to 250C by heat transfer to the surroundings at 250C. Calculate the availability in the initial and final states and the irreversibility for the process. Assume for air Cp= 1.005 kJ/kg.K and R = 0.287kJ/kg.K.
(b) What is third law of thermodynamics? State its significance. [10+6]
5. (a) One Kg – mole of Oxygen undergoes a reversible non – flow isothermal
compression and the volume decreases from 0.15m3/Kg to 0.06m3 /Kg and the initial temperature is 500 C. The gas obeys VanderWaal’s equation during the compression Find:
i. The work done during the process
ii. The Final pressure.
(b) Determine the pressure of air at 2050 C having a specific volume of 0.00315m3/Kg
by means of:
i. Ideal gas equation
ii. Vander Waal?s equation. [8+8]
6. (a) Methane at 150kPa, 200C enters an insulated mixing chamber at a rate of
1.0kg/s .It is mixed with air at 150kPa and 1800 C in an air methane mass ratio of 15:1. The flow is steady and kinetic energy changes are negligible. Ambient pressure and temperature are 100kPa 150C. Determine:
i. The temperature of the mixture leaving the chamber and
ii. The irreversibility of the mixing per kg of methane.
(b) How gravimetric analysis can be compared with volumetric analysis? [10+6]
7. (a) Discuss with the help of graphs the variation of air standard efficiency of an
Otto cycle with compression ratio and adiabatic index.
(b) For air standard diesel cycle the following data are available:
Compression ratio = 16.
Heat added / Kg = 2500 kJ/Kg.
Lowest temperature in the cycle = 3000 K.
Lowest pressure in the cycle = 1 bar.
i. Pressure and temperature at each point in the cycle
ii. Thermal efficiency. [6+10]
8. (a) Discuss the effect of sub cooling on C.O.P. would you desire large sub cooling
(b) A simple saturation ammonia compression system has a high pressure of 1.35
MN/m2 and a low pressure of 0.19 MN/m2, Find per 4,00,000 Kj/hr of re- frigerating capacity, the power consumption of compressor and C.O.P. of the cycle. [4+12]