THERMAL ENGINEERING-II 1.(a). Describe the different processes of rankine cycle; derive the expression for its efficiency and show them on p-v and t-s diagrams. (b) in a rankine cycle, the steam at inlet to turbine is saturated at a pressure of 35bar and the exhaust pressure is 0.2 bar. Determine (i) the rankine efficiency (ii) pump work (iii) turbine work (iv) condenser heat flow (v) the dryness fraction at the end of expansion. Assume flow rate of 9.5 kg/s 2.what are the methods used to increase the efficiency of rankine cycle and explain in detailed any one of them with analysis. 3.(a)Explain the working principle of Babcock and Wilcox boiler with schematic diagram (b) a boiler evaporates 3.6 kg of water per kg of coal into dry saturated steam at 10 bar. The temperature of feed water is 320C.find the equivalent evaporation” from and at 1000C” as well as the factor of evaporation. 4. (a). Give relative merits and demerits of natural draught over artificial draught (b). A chimney is 60m high and the temperature of atmospheric air is 270C.if 15kg of air/kg of fuel is used find for maximum discharge of hot gases (i). The temperature of hot gases (ii) draught pressure in mm of water 5. what is compounding? Describe various ways of compounding impulse turbine and give their merits and demerits 6. (a).describe the changes which occur in a convergent divergent nozzle in detail (b) dry saturated steam at 5 bar with negligible velocity expands isentropically in a convergent divergent nozzle to 1 bar and dryness fraction 0.94.determine the velocity of steam leaving the nozzle 7. (a) what is meant by impulse turbine, give examples (b) The velocity of steam leaving the nozzles of an impulse turbine is 1200 m/s and the nozzle angle is 200 . the blade velocity is 375 m/s and the blade velocity coefficient is 0.75.assume no loss due to shock at inlet, calculate for mass flow rate of 0.5 kg/s and symmetrical balding (i) Blade inlet angle (ii) driving force on the wheel (iii) axial thrust on the wheel (iv) power developed by the turbine 8. (a) what are the difference between fire tube boiler and water tube boiler (b) What is the purpose of fusible plug where it is located in boiler (c) Explain about water level indicator
Posted on: Sat, 03 Aug 2013 05:45:51 +0000