337. For heat economy in the ;turbine cycle, the following parameters should be maintained at rated values at various loads
A.Turbine speed
B.Steam flow
C.Inlet steam pressure and temperature and condenser pressure
D.Turbine vibration
338. The ratio of work done on the blades to the energy supplied to the blades is called
A.Diagram efficiency
B.Nozzle efficiency
C.Stage efficiency
D.Mechanical efficiency
339. The back pressure in steam turbines in Indian conditions is of the order of
A.0.01 ata
B.0.1 ata
C.0.3 ata
D.0.5 ata
340. For a 200 MW plant, the MCR (max. continuous rating) turbine heat rate is of the order of
A.1050 kcal/kWhr
B.1350 kcal/kWhr
C.2050 kcal.kWhr
D.2550 kcal/kWhr
341. If the back pressure of condensing steam turbine rises, then heat rate of turbine will
A.Increase
B.Decrease
C.Remain unaffected
D.First increase upto a certailimit and then decrease
342. The back pressure of condensing steam turbines can be improved by
A.Decreasing steam flow
B.Decreasing steam temperature
C.Injecting water in last stages
D.Using debris filter to clean circulating water and cleaning condenser tubes by rubber ball cleaning equipment
343. The back pressure of a condensing steam turbine, with decrease in temperature of circulating water used in condenser, will
A.Increase
B.Decrease
C.Remain unaffected
D.First increase and then decrease
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