JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B. Tech III Year AIRCRAFT PROPULSION Previous Question Paper (January/February - 2023 - R18)

What different types of components used in typical gas turbine engine. Explain with Sketches.

Give various types of aircraft gas turbine engines and give their relative efficiencies.

Draw profile of liner of typical aircraft combustor with all details.

What is the significance of uniform thermal profile of combustion chamber?

Describe working of supersonic nozzle.

Briefly differentiate nozzle working from aircraft intake.

How significant is solidity and aspect ratio of compressor blade?

Discuss the flow behaviour of axial flow compressor on Ts diagram with neat sketch.

Explain acceleration of gas takes place in turbine passage with neat diagram.

Differentiate between stationary and rotating frame of reference for turbomachinery flow.

Write main strong differences between turboprop and turboshaft engines.

Compare working of ramjet engine with typical turbojet engine.

An aircraft turbojet engine operates adiabatically with components efficiencies for diffuser, compressor, combustor, turbine, and nozzle. Illustrate calculation of total pressure and temperature at the exit of components and nozzle exit velocity of gases.

Define and write equation for thermal, propulsive, and overall efficiencies, for turbojet and turbofan engines.

In detail, describe different types of combustor cooling techniques. (Make use of diagrams and charts to support answer).

With the help of diagrams and sketches, explain about flame stabilization of combustor in details and discuss the significance of various types of stabilizers.

Explain at length, on the working of different types of fuel injectors used for combustor applications.

Elaborate on the performance of annular type of combustor with neat sketch.

Distinguish between isentropic and adiabatic expansion of convergent-divergent nozzles.

Give an elaborate note on losses that occurred in the aerospace engine nozzles.

Describe about ejector and variable area nozzles.

Discuss the aerothermodynamic behavior of low subsonic CD nozzle with the help of Ts diagram.

An axial compressor operating for maximum pressure. Analyse how it develops stall and surge. (use neat sketches to support answer).

Symmetric Velocity triangle for compressor blade at hub has absolute flow angle 13° and velocity 99m/s. Rotor rotates at a mean speed of 238m/s. Draw velocity triangles for 49.99% DOR, at mean and tip locations, if hub to tip radius ratio of blade is 0.68.

With illustrations, explain the working of axial flow compressor. (Make use of equations, diagrams, and charts).

Air enters an axial fan rotor of mean radius of 160mm. Circumferential component of absolute velocity is increased by 19m/s through rotor. Rotational speed of shaft is 3333rpm. Compressor is operating a flow rate of 0.48 m³/s with inlet pressure and temperature 101325Pa and 295°K respectively. Find torque exerted and power transferred.

Illustrate different types of turbine cooling techniques.

Combustion gases enters gas turbine that has blade tip diameter 0.68m, and blade height 0.109 m. Total pressure and temperature of gas are 3.86 bar and 1160 K. The shaft speed of rotor is 1099 rpm. At mean radius stage operates with DOR 50%, flow coefficient 0.678 and blade loading factor 2.6. Draw velocity polygons and stage blade profiles.

Explain the functioning of impulse turbine with neat sketches and charts.

Heated combustion gases of burner enter axial flow turbine that has blade height 0.127m, and blade hub diameter 0.61m. Stagnation temperature and pressure of hot gases are 1320°K bar and 3.69bar. The speed of turbine rotor is 1170 rpm. Stage has DOR 50%, blade loading factor 2.61 and flow coefficient 0.66 at mean radius. Draw stage blade profiles and velocity polygons.