JNTU
JNTU B.Tech III AEROSPACE PROPULSION I Previous Question Paper (May/June - 2019 - R13)
Part A is compulsory which carries 25 marks. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit. Each question in Part B carries 10 marks.
Part A
What is the criteria for engine selection.
Answer
The primary criteria for engine selection are mission requirements (range, payload, speed, and altitude), fuel economy (specific fuel consumption), weight-to-thrust ratio, reliability, maintenance cost, and environmental considerations such as noise and emissions.
Draw the graph showing the variation of total pressure, velocity, Temperature across a turbojet engine.
Answer
The variation of properties across a turbojet engine follows this trend: Total pressure increases in the compressor and decreases slightly in the burner and turbine. Total temperature remains constant in the intake, increases significantly in the compressor and combustion chamber, and decreases through the turbine and nozzle. Velocity decreases in the diffuser, remains relatively low through the compressor and burner, increases through the turbine, and increases sharply through the nozzle.
Write the expression for components and turbine efficiency.
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What are different phases an aircraft undergoes during off-design operation?
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State the functions of an air intake in a gas turbine engine.
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Explain flammability limits with a neat graph.
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What is purpose of cascade analysis of compressor stage?
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What are the various blade stresses in an axial flow turbine?
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What are the conditions that should be satisfied to ensure perfect component matching in a gas turbine engine?
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Draw performance map of two stage axial flow turbine and indicate choked points.
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Part B
Explain about types of air breathing engines.
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Explain the performance parameters effecting total efficiency.
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Write about merits and demerits of turbofan with turbo prop engine.
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Derive an equation for thermal efficiency of a Brayton cycle.
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Explain the main burner components and their function with neat diagrams.
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Discuss the functions of nozzle and its performance during back pressure control in a gas turbine engine.
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With a neat sketch, explain the operation of a mixed compression air intake.
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Explain the aerodynamics and thermodynamics of internal compression supersonic air intake.
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What is aerodynamic choking of flow? Explain in detail.
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Draw the velocity triangles at the inlet and outlet of the rotor and derive an expression for the work done per stage.
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Explain the following terms:
Degree of reaction
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Stage loading
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Work done factor
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Flow Coefficient
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Solidity.
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Differentiate between engine performance analysis and parametric cycle analysis. What is the relevance of compressor operating line?
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What are the dimensionless and corrected parameters used in engine performance analysis? Explain their need.
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Write short notes on with neat diagrams: i) Turbine performance maps ii) Compressor operating line.
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