AE 2202 AERO ENGINEERING THERMODYNAMICS SECOND UNIT EXAMINATION

B.E./B.TECH.DEGREE SECOND UNIT EXAMINATIONS, AUGUST - 2012

REGULATIONS 2008

SECOND YEAR / THIRD SEMESTER

AE 2202 AERO ENGINEERING THERMODYNAMICS

AERONAUTICAL ENGINEERING

Time: 90 Mins                                     Date:   08.08.2012                              Maximum:50 marks

ANSWER ALL QUESTIONS

                                                                  PART – A                        (9 x 2 =18marks)

1.     What is meant by reversible and irreversible process?

2.     Explain Zeroth Law and first law of thermodynamics?

3.     What are the limitations of first law of thermodynamics?

4.     Why Carnot cycle cannot be realized in practical?

5.     What are the important characteristics of entropy?

6.     Define the term enthalpy and entropy

7.     What is perpetual motion machine of first kind and second kind?

8.     State the Kelvin – Plank and Clausius statement of second law of thermodynamics

9.     State Carnot’s theorem. What are the Corollaries of Carnot theorem?

                                                      PART – B                       (2 x 16 =32 marks)

ANSWER ANY TWO QUESTIONS

10.                        Derive the relationship between P-V-T, work done, change in internal energy , Heart transfer, change in enthalpy change in entropy and plot the P-V & T-S diagram for isentropic process.

11.                        Air is contained in a cylinder fitted with a frictionless piston. Initially the cylinder contains  0.5m³ of air at 150 kPa, 20°C. The air is then compressed reversibly according to the relation  PVⁿ = constant, until the final pressure is 600 kPa, at which point the temperature is 120°C.  For this process, determine,

                   (i) The polytropic exponent n

                   (ii) The final volume of air

                   (iii) The work done on the air and the heat transfer and

                   (iv) The net change in entropy. 

12.                        Air at a temperature of 15⁰C passes through a heat exchanger at a velocity of 30 m/s where its temperature is raised to 800⁰C. It then enters a turbine with the same velocity of 30 m/s and expands until the temperature falls to 650⁰C. On leaving the turbine, the air is taken at a velocity of 60 m/s to a nozzle where it expands until the temperature has fallen to 500⁰C. If the air flow rate is 2 kg/s, calculate :

          (i) The rate of heat transfer to the air in the heat exchanger.

          (ii) The power output from the turbine assuming no heat loss and

          (iii) The velocity at exit from the nozzle, assuming no heat loss.

Take the enthalpy of air as h = Cp.T, where Cp is the specific heat equal to 1.005 kJ/kg–K and ‘‘T’’ the temperature.