JNTU B.Tech III THERMODYNAMICS AND REFRIGERATION SYSTEMS Previous Question Paper (May - 2018 - R15)

Define state, path, process.

Explain Clausius statement for second law of thermodynamics.

Explain the Carnot cycle with neat P-V and T-S chart.

List any four various types of mountings in steam boilers.

Define the terms i) Brake Thermal efficiency ii) mechanical efficiency iii) Friction power.

Explain the Diesel cycle with a neat P-V chart, indicate the various processes.

Define C.O.P.

Draw the layout of bell Coleman refrigeration cycle and explain all processes.

Draw the layout of ammonia water Vapour absorption Refrigeration system.

Define Relative humidity, sensible heat, latent heat.

Write short notes on the following: Closed system, isolated system, open system, zeroth law of thermodynamics.

A tank containing air is stirred by a paddle wheel. The work input to the paddle wheel is 9000 kJ and the heat transferred to the surroundings from the tank is 3000 kJ. Determine: i) Work done; ii) Change in internal energy of the system.

Explain the Kelvin Plank’s and Clausius statement of second law of thermodynamics

A vessel of capacity 3 m³ contains 1 kg mole of N₂ at 90^oC. i) Calculate pressure and the specific volume of the gas. ii) If the ratio of specific heats is 1.4, evaluate the values of c_p and c_v. iii) Subsequently, the gas cools to the atmospheric temperature of 20^oC; evaluate the final pressure of gas.

What do you mean by the term ‘Entropy’ ? Prove that entropy is a property of a system.

Explain with a neat sketch the working of a Lancashire Boiler.

Explain various accessories for steam boilers with neat sketches.

Differentiate between fire tube and water tube boilers.

Derive the expression for air standard efficiency of Otto cycle.

The stroke and cylinder diameter of a compression ignition engine are 250 mm and 150 mm respectively. If the clearance volume is 0.0004 m³ and fuel injection takes place at constant pressure for 5 per cent of the stroke determine the efficiency of the engine. Assume the engine working on the diesel cycle.

Explain mechanical efficiency, overall efficiency, indicated thermal efficiency, Brake thermal efficiency of I.C engine.

The diameter and stroke length of a single cylinder two stroke gas engine working on the constant volume cycle are 200 mm and 300 mm respectively with clearance volume 2.78 liters. When the engine is running at 135 r.p.m, the indicated mean effective pressure was 5.2 bar and the gas consumption is 8.8 m³/hour. If the calorific value of the gas used is 16350 kJ/m³, find i) Air standard efficiency; ii) Indicated power developed by the engine and iii) Indicated thermal efficiency of the engine.

Explain the principle of reversed Carnot cycle refrigeration system with a neat sketch.

A refrigerating system operates on the reversed Carnot cycle. The higher temperature of the refrigerant in the system is 35^oC and the lower temperature is – 15^oC. The capacity is to be 12 tonnes. Neglect all losses. Determine: i) Co-efficient of performance. ii) Heat rejected from the system per hour. iii) Power required.

A refrigerating machine of 6 tonnes capacity working on Bell-Coleman cycle has an upper limit of pressure of 5.2 bar. The pressure and temperature at the start of the compression are 1.0 bar and 16^oC respectively. The compressed air cooled at constant pressure to a temperature of 41^oC enters the expansion cylinder. Assuming both expansion and compression processes to be adiabatic with γ = 1.4, calculate Co-efficient of performance.

Discuss the merits and demerits of air refrigeration system.

Explain simple Vapour Compression refrigeration Cycle on Temperature-Entropy (T-S) and P-H charts.

Discus the effect of suction pressure and sub cooling vapor compression refrigeration cycle on its C.O.P.

Explain the working of a domestic refrigerator with a neat sketch.

40 m³ of air at 35^oC DBT and 50% R.H. is cooled to 25^oC DBT maintaining its specific humidity constant. Determine: (i) Relative humidity (R.H.) of cooled air; (ii) Heat removed from air.