JNTU
JNTU B.Tech III AERODYNAMICS II Previous Question Paper (November/December - 2017 - R13)
Note: This question paper contains two parts A and B. 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 carries 10 marks and may have a, b, c as sub questions.
Part A
What is irreversibility? How to account for it? Explain.
Answer
Irreversibility refers to a process that cannot be reversed to restore the system and surroundings to their initial states without leaving a net change in the universe. It is caused by dissipative effects such as friction, unrestrained expansion, and heat transfer across a finite temperature difference. It is accounted for by calculating entropy generation (S_gen) within the system, where the actual process is compared to an ideal, reversible process.
Can the internal energy of gas be converted into useful work? Discuss.
Answer
Yes, the internal energy of a gas can be converted into useful work. According to the first law of thermodynamics, internal energy can be transformed into work through expansion processes, such as in a piston-cylinder arrangement or a turbine. However, the second law of thermodynamics dictates that this conversion is limited by the thermal efficiency of the cycle, meaning not all internal energy can be converted into work; some must be rejected as heat.
Excluding density, what other parameters differentiate compressible flow from incompressible flow, so far the aerodynamics is concerned.
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Why Mach number plays a significant role, rather than velocity, in the description of aerodynamics of flow?
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For every given situation of flow, there are two types of solutions, weak and strong. Which is appropriate solution to be adapted? Discuss.
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Discuss pressure deflection diagram for supersonic flow over wedge.
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Discuss the aerodynamics of supercritical aerofoil.
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How to ensure that flow across CD nozzle is isentropically expanded without any losses?
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Briefly, explain about method of characteristics.
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Discuss the Newtonian model for hypersonic flow.
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Part B
Air enters an insulated compressor operating at steady state at 1 bar and 30 degree centigrade with working substance moving at 4500 kg/ hour. It exits at 9 bar. Neglecting kinetic and potential energy, find a) minimum power require and corresponding exit temperature b) isentropic compressor efficiency if exit temperature is 350 degree centigrade.
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A chamber is divided into two compartments by a thermally conducting piston. The chamber is insulated. There is one cubic meter of saturated water vapor of 5 MPa in one compartment while the other has one cubic meter of water vapor at 25 MPa, 900 0C. The piston is released for equilibrium without it experiencing no change of state. Determine the following, for water a) Final pressure and temperature b) entropy rise that takes place.
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What are different possible forms of energy for a thermodynamic system? Discuss significance of each form of energy.
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The flow upstream of normal shock is moving with 1 atm pressure at 290 degree kelvin temperature at a mach number of 2.5. Calculate properties of flow downstream the shock and related entropy change.
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Show that the rise in entropy across normal shock results in decrease in total pressure.
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The entropy rise across normal shock is 200 J/kg.K. Determine the upstream Mach number. If upstream pressure and temperature are 1 atm and 290 kelvin, find down values.
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Enumerate the effects of shock and boundary layer interaction in supersonic flow.
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An oblique shock generated at a compression corner of 18 degrees kelvin is being reflected by a horizontal wall surface above the corner. The properties of flow upstream are Mach no. 3.5, pressure 1.2atm and 400 degree kelvin. Calculate properties downstream reflected shock.
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Write short notes on following: i) Shock reflection of same family ii) Shock reflection of opposite family.
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Estimate the exact values of Mach number static pressure, temperature and density for a flow that is initially deflected upstream by 20 degrees and expanded by 10 degrees later. The approach properties of the flow are 3.0 Mach no, 1.1atm pressure and 330 degree kelvin.
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What is drag divergence? What is its significance in the design of high speed aircraft?
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A flow is ideally expanding across a supersonic convergent-divergent nozzle, where reservoir and exit pressure are 2 atm and 0.7 atm. Determine the area ratio of the nozzle.
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What happens to flow at the exit, if it is under expanded across nozzle? Explain with charts and equations.
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For an isentropically expanding flow across a nozzle the reservoir conditions are 6 atm pressure and 360 degree kelvin. If its exit to throat area ratio is 2.25, determine exit Mach number, static pressure, temperature, density and velocity, when the flow is subsonic at the exit and sonic at the throat.
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Explain the aerodynamics of Subsonic and supersonic leading edge delta wings. (Make use of sketches and charts and equations).
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Bring out any 20 qualitative aerothermodynamic differences between hypersonic and supersonic flows.
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