JNTU
JNTU B.Tech III THERMAL ENGINEERING II Previous Question Paper (November/December - 2018 - 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 carries 10 marks.
Part A
Answer all sub-questions:
Draw the P-V diagram and T-s diagram of Reheat cycle.
Answer
The P-V diagram for a reheat cycle shows expansion in two stages (high-pressure and low-pressure turbines) with a constant pressure heat addition process between them. The T-s diagram shows the expansion lines 3-4 and 5-6 with a constant pressure heating process 4-5 at the reheat pressure, resulting in increased quality of steam at the turbine exhaust.
Write the significance of adiabatic flame temperature.
Answer
Adiabatic flame temperature is the maximum temperature attained by the products of combustion under adiabatic conditions (no heat loss). It is significant for determining the thermal limits of combustion chamber materials, assessing the efficiency of the combustion process, and predicting the potential for pollutant formation like NOx.
Write the significance of mountings of a boiler.
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Explain the working principle of a nozzle.
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Draw velocity diagram at inlet for impulse turbine.
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Explain the working principle of draft in the condenser.
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What is the purpose of inter cooling in gas turbine.
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Draw two combustion chambers of gas turbine plant.
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Write equations for propulsive efficiency and thermal efficiency of jet propulsion engine.
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Explain solid propellant rocket engine.
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Part B
What is meant by the concept of mean temperature of heat addition in Rankine cycle?
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A steam power plant running on Rankine cycle has steam entering HP turbine at 20 MPa, 500C and leaving LP turbine at 90% dryness. Considering condenser pressure of 0.005 MPa and reheating occurring upto the temperature of 500C determine (i) The pressure at which steam leaves HP turbine (ii) The thermal efficiency.
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Write the steps involved in the determination of air requirement for complete combustion.
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Using orsat analysis, explain the flue gas analysis.
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Classify the boilers based on the temperature and pressure limits.
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Draw the line diagram of volex boiler and mention its pressure limits.
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Derive the equation for maximum discharge in nozzles.
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In a nozzle steam expands from 12 bar and 300C to 6 bar with flow rate of 5 kg/s. Determine throat and exit area if exit velocity is 500 m/s and velocity at inlet to nozzle is negligible. Also find coefficient of velocity at exit.
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Draw the free hand sketch and explain velocity compounded impulse turbine.
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In a single stage impulse turbine the isentropic enthalpy drop of 200 kJ/kg occurs in the nozzle having efficiency of 96%. Determine blade angles, efficiency, power developed and axial thrust.
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What is the principle of Ejector condenser and explain the working with line diagram of the same.
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A Parson’s reaction turbine has mean diameter of blades as 1.6 m and rotor moving at 1500 rpm. Determine stage efficiency and blade height.
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Draw line diagram and explain Regenerative gas turbine cycle.
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A gas turbine unit receives air at 2 bar, 300 K and compresses it adiabatically to 6.2 bar. Calculate the work of turbine and compressor and thermal efficiency.
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Explain the need and significance of inter cooling in gas turbines.
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In a gas turbine installation air is supplied at 1 bar, 27C. Determine cycle efficiency, work ratio and specific work output.
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Derive the equation for propulsive power of jet propulsion engine.
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A jet propulsion engine moves with speed of 200 m/s at an altitude. Determine power required to run compressor, air-fuel ratio, total pressure of gas leaving turbine, thrust per flow rate and plot processes on h-s diagram.
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Draw line diagram and explain the working of liquid propellant rocket engine.
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Compare and contrast turbojet engine with Rocket propulsion engine in all aspects.
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