Compressors, Gas Turbines and Jet Engines MCQs

Question 1

The pressure ratio for an open cycle gas turbine compared to closed cycle gas turbine of same h.p. is

Accepted Answer

Low

Answer

High

Answer

Same

Answer

Low/high depending on make and type

Question 2

Air-fuel ratio in a jet engine will be of the order of

Accepted Answer

60 : 1

Answer

10 : 1

Answer

15 : 1

Answer

20 : 1

Question 3

The ratio of the increase in pressure in rotor blades to total increase in pressure in the stage is called

Accepted Answer

Degree of reaction

Answer

Pressure ratio

Answer

Pressure coefficient

Answer

Slip factor

Question 4

Pick up the wrong statement

Accepted Answer

Pulse-jet requires no ambient air for propulsion

Answer

Ramjet engine has no turbine

Answer

Turbine drives compressor in a Turbojet

Answer

Bypass turbojet engine increases the thrust without adversely affecting, the propulsive efficiency and fuel economy

Question 5

Pick up the wrong statement

Accepted Answer

Axial flow compressors are bigger in diameter compared to centrifugal type

Answer

Centrifugal compressors deliver practically constant pressure over a considerable range of capacities

Answer

Axial flow compressors have a substantially constant delivery at variable pressures

Answer

Centrifugal compressors have a wider stable operating range than axial flow compressors

Question 6

Pick up the wrong statement

Accepted Answer

Axial flow compressors are more stable than centrifugal type compressors but not as efficient

Answer

Large gas turbines employ axial flow compressors

Answer

Axial flow compressors have high capacity and efficiency

Answer

Axial flow compressors have instability region of operation

Question 7

The volumetric efficiency of a compressor falls roughly as follows for every 100 m increase in elevation

Accepted Answer

1.0%

Answer

0.1%

Answer

0.5%

Answer

5%

Question 8

Rotary compressors are used for delivering

Accepted Answer

Large quantities of air at low pressures

Answer

Small quantities of air at high pressures

Answer

Large quantities of air at high pressures

Answer

Small quantities of air at low pressures

Question 9

The air entry velocity m a rocket as compared to aircraft is

Accepted Answer

Zero

Answer

Same

Answer

More

Answer

Less