JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech III AEROSPACE PROPULSION - I Previous Question Paper (July/August - 2023 - R13)
Note: i) Question paper consists of Part A, Part B. ii) Part A is compulsory, which carries 25 marks. In Part A, Answer all questions. iii) In Part B, Answer any one question from each unit. Each question carries 10 marks and may have a, b as sub questions.
Part A
Define the terms: Gross thrust and net thrust.
Answer
Gross thrust is the total thrust produced by the engine nozzle, calculated as the product of mass flow rate and exit velocity plus the pressure thrust term. Net thrust is the actual useful thrust available for propulsion, obtained by subtracting the ram drag (momentum of the incoming air) from the gross thrust.
Write the differences between open cycle and close cycle gas turbine engine.
Answer
In an open cycle, the working fluid (air) is drawn from the atmosphere, processed through the engine, and exhausted back into the atmosphere. In a closed cycle, the working fluid is continuously recirculated within the system, requiring an external heat source and a heat exchanger to reject heat before re-entering the compressor.
What is figure of merit?
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Explain about design point performance.
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What is aerodynamic choking?
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What is the purpose of primary nozzle and fan nozzle?
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Define surge.
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What are the various flow losses in axial flow compressors?
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What is corrected performance?
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Write a short note on compressor – turbine matching.
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Part B
Write a short note on operating envelope of flight vehicles.
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What is the effect of flight conditions and jet exit speed on performance of the propulsive system?
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Explain in detail about the role of propulsion in aircraft performance.
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Draw a T-s and p-v plot of an ideal turbofan engine and explain its working.
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Derive an expression for thermal efficiency of a turbojet with reheat.
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Explain the aerodynamics of a typical subsonic inlet. What are the types of subsonic inlets?
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What are the various thrust vectoring mechanisms available? Explain.
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Explain the three-dimensional flow in axial flow compressor and derive the free vortex condition. What does free vortex condition signify?
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The following particulars of a single stage turbine of free vortex are given below: Total head inlet pressure = 4.6 bar, Total head inlet temperature = 700oC, Static head pressure at mean radius = 1.6 bar, Mean blade diameter/blade height = 10, Nozzle loss coefficient = 0.10, Nozzle outlet angle = 28o. Determine the gas temperature, velocities, and discharge angle at the blade root and tip radii. Take Cp = 1.147, γ = 1.33 and mass flow rate = 20 kg/s.
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Explain the significance and requirements for component matching.
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Explain gas generator with neat sketches.
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Derive an expression for relation between compressor pressure ratio, mass flow rate, efficiency, engine speed.
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