1. Explain the Joule Thompson coefficient and Inversion curve.

2. The percentage of composition by mass of a solid fuel used in boiler is given below C H2 O2 N2 S and remainder being ash.
Determine the mass of air per kg of fuel for complete combustion and mass of dry products formed per kg of fuel.

3. Explain why safety valves are needed in a boiler. Draw the neat sketch of a spring loaded safety valve and explain its working.

4. Find the mass of flue gases flowing through a chimney when draught produced is equal to 2 em of water. Temperature of flue gases is 297°C and the ambient temperature is 27°C. The flue gases formed per kg of fuel burnt is 20 kg. Diameter of the chimney is 2 m. Neglect the losses.

5. State the methods of governing of steam engines and discuss anyone method in detail.

6. Steam at a pressure of 15 bar and with 50°C of superheat is allowed to expand in a convergent-divergent nozzle. The exit pressure is 1 bar. If the nozzle is required to supply 2 kg/s of steam, then find the velocity at throat and exit, areas at throat and exit.

7. Discuss with the help of T-s diagram the effect of the following variables on efficiency and power output of a Rankine cycle:

Inlet pressure

Condenser pressure

Inlet temperature with inlet pressure maintained constant

8. Steam enters the blade row of an impulse turbine with a velocity of 600 m/s at an angle of 25°C to the plane of rotation of blades. The mean blade speed is 255 m/s and the blade angle at exit is 30°. The blade friction coefficient is 10%.

Determine the

blade angle at inlet,

work done/kg of steam,

axial thrust, and

diagram efficiency.

9. Show that the optimum pressure ratio for the maximum specific work output of a gas turbine cycle is



where Tmax and Tmin are the maximum and minimum temperatures of the cycle.

10. Write short notes on the following:

Principle of rocket propulsion

Effects of air leakage on condenser