Engineering :: Turbo machines

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31.

For efficient operation of axial flow compressors the blades are made

A.	straight	B.	slightly curved
C.	aerofoil section	D.	forward curved

32.

Thermal efficiency of a gas turbine is in the range

A.	50 to 60 percent	B.	40 to 50 percent
C.	30 to 40 percent	D.	20 to 30 percent

33.

The efficiency of a simple open cycle gas turbine depends upon

A.	pressure ratio	B.	compressor efficiency
C.	turbine inlet temperature	D.	All of the above

34.

Which of the following steam turbine has identical fixed and moving blades?

A.	Curtis turbine	B.	Rateau turbine
C.	Parson's turbine	D.	none of the above

35.

Which of the following is a pressure compounded turbine?

A.	Parson's turbine	B.	Curtis turbine
C.	Rateau turbine	D.	All of the above

36.

The continuity equation in compressible fluids is derived on the basis of

A.	conservation of momentum	B.	conservation of energy
C.	conservation of mass	D.	conservation of velocity head

37.

As there is plenty of time for heat transfer across the walls, the flow in long pipes at low velocities attains

A.	isentropic conditions	B.	adiabatic conditions
C.	isothermal conditions	D.	polytropic conditions

38.

In a hot wire anemometer the rate of heat loss from sensing element is a function of

A.	pressure	B.	mass rate of flow
C.	velocity of flow	D.	none of the above

39.

The normal shock wave in compressible flow is analogous to

A.	surges in open channel	B.	vortex formation in centrifugal pump
C.	hydraulic bore in tidal rivers	D.	hydraulic jump in channel flow

40.

A roots blower compresses 0.06 cubic metres of air from 1.0 bar to 1.45 bar per revolution. The compressor efficiency is nearly

A.	99%	B.	87%
C.	75%	D.	63%