SPPU Mechanical Engineering (Semester 7)
Gas Turbine Propulsion
December 2016
Total marks: --
Total time: --
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary

Solve any one question from Q.1(a,b) & Q.2
1(a) Write a note on ideal and actual Brayton cycle.
3 M
1(b) In a gas turbine plant, the suction occurs at 1 bar and 27&Deg;C. The air is compressed to 4 bar. Maximum temperature is 572°C. Find the air-fuel ratio. Assume isenttropic efficiency of compressor & turbine, as 85%. Take Cp for air & gases as 1.005 and 0.97kJ/kgK, respectively, C.V= 42MJ/kg.
7 M

2 Write notes on:
a) Rocket propulsion.
ii) Polytropic efficiency of compressor & turbine.
10 M

Solve any one question from Q.3(a,b) & Q.4(a,b)
3(a) Write a note on the various parameters affecting the flight performance.
4 M
3(b) Explain the working of turbofan engine.
6 M

4(a) Discuss Nozzle & difusser losses.
5 M
4(b) What do you understand by the term air-breathing engines? How are they classified?
5 M

Solve any one question from Q.5(a,b) & Q.6(a,b)
5(a) Explain the effect of nozzle angle on work output and effect of axial discharge in an axial flow turbine.
6 M
5(b) In a single axial flow turbine (impulse type), the expansion in the nozzle occurs from 4bar, 650°C to a press of 1 bar. The discharge angle is 15° The blade speed is 360m/s and the gas leaves the rotor blade in axial direction with a speed is 360m/s and the gas leaves the rotor blade in axial direction with a speed of 300 m/s. Assuming a nozzle efficiency of 96% Find:
i) Rotor blade angles at inlet and oulet.
ii) Utilization factor.
iii) Power developed for 25kg/sec of gas flow.
iv) Stage efficiency.
10 M

6(a) Discuss the performance curves of gas turbines.
6 M
6(b) Gas enters in an impulse turbine(1-stage) at a stagnation pressure of 4 bar while th exit static pressure is 1.18 bar. Stage exit velocity is 290m/s(axial) & nozzle efficiency is 96%. The blade velocity is 320m/s. The static head efficiency is 88%. The exit pressure from the nozzle is 1.25 bar. Find:
i) W.D. per kg of air.
ii) Nozzle angle.
iii) Blade inlet and outlet angle.
iv) Energy utilization factor for the rotor.
10 M

Solve any one question from Q.7(a,b) & Q.8
7(a) Explain the processes involved in an axial flow compressor with the help of T-s diagram.
6 M
7(b) Write notes on:
i) Flow coefficient &stage efficiency.
ii) Degree of reaction and workdone factor.
10 M

8 Write notes on:
a) Radial & axial flow compressors
b) Factors affecting pressure ratio.
c) Inlet & Outlet velocity triangle.
16 M

Solve any one question from Q.9(a,b) & Q.10
9(a) Explain the different types of combustion chambers used in gas turbines.
9 M
9(b) Write notes on:
i) Desirable features of combustion chambers of a gas turbine.
ii) Combustion chamber arrangements.
9 M

10 Write notes on:
a) Off-design characteristics of gas turbines.
b) Stability limits and combusion intensity.
c) Component characteristics of compressor &turbine.
18 M

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