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Thursday, 27 February 2014

Powerplant technology- model question paper for B.E/B.Tech/M.E/M.Tech Engineering

1 (a) Write a note on subcooled liquids. (4 Marks)
(b) Draw and explain T-s diagram of an internally irreversible superheat Rankine cycle. Explain the working of a closed type feedwater heaters with drains cascaded backward. (8 Marks)
(c) What is cogeneration? Explain economics of cogeneration. (4 Marks)
(d) A water pump compresses saturated water at 1 to 2500 psia. The pump efficiency is 0.70. Find the ideal and actual pump and the water exit temperature. (4 Marks)
2 (a) Differentiate between straight-tube boiler and bent-tube boiler. (6 Marks)
(b) Explain the different stages of pulverizing process. (6 Marks)
(c) Explain any two forms of biomass conversion. (4 Marks)
(d) A 200 m high 4 m diameter stack emits 1000 kg/s of 100oC gases into 5oC air. The prevailing wind velocity is 50 km/hr. The atmosphere is in a condition of neutral stability. Calculate the height of the gas plume by two methods. (4 Marks)
3 (a) Using a neat velocity diagram explain the working of a two stage reaction turbine. (6 Marks)
(b) Write a note on turbine losses. (6 Marks)
(c) Explain the processes involved in a water makeup system. (4 Marks)
(d) A single effect evaporator receives motive steam at 7 bars and 180oC and pretreated raw water at 9 bars and 16oC. It has 123 m2 of heat transfer area. Calculate the mass flow rates of motive steam and vapour produced in kilograms per second. Ignore the pressure drop in the evaporator. (4 Marks)
4 (a) Explain the mechanisms by which wet-cooling towers dissipate heat rejected by the plant to the environment. (6 Marks)
(b) What is a fill? What are the two types of fill? (4 Marks)
(c) Show that the efficiency of an ideal Brayton cycle at the optimum pressure ratio is a function of minimum and maximum temperatures only, and independent of the working fluid. (6 Marks)
(d) A helium gas turbine cycle has compressor and turbine polytropic efficiencies of 0.8 and 0.9 and pressure ratios of 2.5 and 2.4 respectively. The compressor has one stage of intercooling and turbine has one stage of reheat. The cycle has a generator with 85% effectiveness. The cycle minimum and maximum temperatures are 100 and 2000oF respectively. Calculate (a) the cycle efficiency, and (b) the cycle power for a helium mass flow rate of 200 lbm/s. (4 Marks)
5 (a) Explain nuclear fission and fusion. (4 Marks)
(b) Write and explain Maxwell distribution law. (4 Marks)
(c) Explain in detail different methods to control a nuclear reactor. (8 Marks)
(d) Radium 226 decays into radon gas. Compute the decay constant and the initial activity of 1 g of radium 226. The atomic mass is 226.0245 amu. (4 Marks)
6 (a) Draw core cross section of PWR reactor. Explain. (4 Marks)
(b) What are pebble-bed reactors? (4 Marks)
(c) Write a note on Clinch River breeder reactor project. (8 Marks)
(d) A large commercial gas-cooled fast breeder reactor using a plutonium-uranium mixed oxide fuel has a breeding ratio of 1.5 and a compound doubling time of 6 years. Estimate the average neutron flux in the reactor. Assume that the fuel in the core represents 80 % of the reactor fuel inventory. (4 Marks)
7 (a) Geothermal sources are of three kinds. Explain. (6 Marks)
(b) Explain using a neat figure, the working of a liquid dominated single flash steam system. (6 Marks)
(c) Differentiate between geothermal-preheat hybrid systems and fossil-superheat hybrid systems. (4 Marks)
(d) What is land surface subsidence? Explain. (4 Marks)
8 (a) Write a note on heliostats. (4 Marks)
(b) Write expressions for lift force and drag force. Explain the terms. (4 Marks)
(c) Write notes on thermal sensible energy storage and latent heat energy storage. (8 Marks)
(d) An ocean wave power system of the float type uses a 25 cm thick float in 2m waves that have 60 m wavelength. The cylinder has a diameter of 1 m. The compressor pressure ratio is 10. The air is at 1 atm at 10oC. Calculate the power produced by the turbine if the compressor-turbine system has an efficiency of 76 percent of ideal. (4 Marks)

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