JNTU
JNTU B.Tech II THERMODYNAMICS FOR AEROSPACE ENGINEERING Previous Question Paper (February - 2024 - R22)
Note: This question paper contains two parts A and B. Part-A is a compulsory question. Part-B consists of ten questions (numbered from 2 to 11) carrying 10 marks each. From each unit, there are two questions, and the student should answer one of them. Hence, the student should answer five questions from Part-B.
Part A
Define Zeroth law of Thermodynamics.
Answer
The Zeroth Law of Thermodynamics states that if two systems are each in thermal equilibrium with a third system, they are in thermal equilibrium with each other.
Differentiate between extensive and intensive property.
Answer
An intensive property is independent of the mass of the system (e.g., pressure, temperature), whereas an extensive property depends on the total mass or size of the system (e.g., total volume, total energy).
State Kelvin Planck’s Statement of second Law.
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What is the corollary of Carnot’s Theorem?
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Define latent heat of sublimation and dryness fraction.
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What is a pure substance?
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What do you mean by regeneration?
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State the four processes of Diesel cycle.
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What do you understand by dry and wet compression?
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What are the most widely used refrigerants?
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Part B
A steam turbine drives a ship’s propeller through an 8: 1 reduction gear. The average resisting torque imposed by the water on the propeller is 750 × 103 Nm and the shaft power delivered by the turbine to the reduction gear is 15 MW. The turbine speed is 1450 rpm. Determine (a) the torque developed by the turbine, (b) the power delivered to the propeller shaft, and (c) the net rate of working of the reduction gear.
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Derive an expression of Steady flow energy equation for a single stream entering and a single stream leaving a control volume.
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If a gas of volume 6000 cm3 and at pressure of 100 kPa is compressed quasi-statically according to
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If 20 kJ are added to a Carnot cycle at a temperature of 100°C and 14.6 kJ are rejected at 0°C, determine the location of absolute zero on the Celsius scale.
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Discuss in detail with the help of mathematical expression about the maximum work in a reversible process.
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Prove that the COP of a reversible refrigerator operating between two given temperatures is the maximum.
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Draw the phase equilibrium diagram for a pure substance on p-T coordinates. Why does the fusion line for water have negative slope?
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A rigid vessel of volume 0.86 m3 contains 1 kg of steam at a pressure of 2 bar. Evaluate the specific volume, temperature, dryness fraction, internal energy, enthalpy, and entropy of steam.
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A rigid vessel contains 1 kg of a mixture of saturated water and saturated steam at a pressure of 0.15 MPa. When the mixture is heated, the state passes through the critical point. Determine: a) The volume of the vessel b) The mass of liquid and of vapour in the vessel initially.
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Obtain an expression for the specific work done by an engine working on the Otto cycle in terms of the maximum and minimum Temperatures of the cycle, the compression ratio rk, and constants of the working fluid. Hence show the compression ratio for maximum specific work output.
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An air standard limited pressure cycle has a compression ratio of 15 and compression begins at 0.1 MPa, 40°C. The maximum pressure is limited to 6 MPa and the heat added is 1.675 MJ/kg. Compute (a) the heat supplied at constant volume per kg of air, (b) the heat supplied at constant pressure per kg of air, (c) the work done per kg of air, (d) the cycle efficiency, (e) the temperature at the end of the constant volume heating process, (f) the cut-off ratio, and (g) the m.e.p. of the cycle.
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A Refrigerant-12 vapour compression cycle has a refrigeration load of 3 tonnes. The evaporator and condenser temperatures are – 20°C and 40°C respectively. Find (a) The refrigerant flow rate in kg/s (b) The volume flow rate handled by the compressor in m3/s (c) The work input to the compressor in kW (d) The heat rejected in the condenser in kW (e) The isentropic discharge temperature. If there is 5° C of superheating of vapour before it enters the compressor, and 5°C sub cooling of liquid before it flows through the expansion valve, determine the above quantities.
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A vapour compression refrigeration system uses R-12 and operates between pressure limits of 0.745 and 0.15 MPa. The vapour entering the compressor has a temperature of – 10°C and the liquid leaving the condenser is at 28°C. A refrigerating load of 2 kW is required. Determine the COP and the swept volume of the compressor if it has a volumetric efficiency of 76% and runs at 600 rpm.
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