Compressors, Gas Turbines and Jet Engines MCQs

Question 1

A rocket engine for the combustion of its fuel

Accepted Answer

Carries its own oxygen

Answer

Uses surrounding air

Answer

Uses compressed atmospheric air

Answer

Does not require oxygen

Question 2

The ratio of the volume of free air delivery per stroke to the swept volume of the piston, is known as

Accepted Answer

Volumetric efficiency

Answer

Compressor efficiency

Answer

Isothermal efficiency

Answer

Mechanical efficiency

Question 3

More than one stage will be preferred for reciprocating compressor if the delivery pressure is more than

Accepted Answer

2 kg/cm2

Answer

6 kg/cm2

Answer

10 kg/cm2

Answer

14.7 kg/cm2

Question 4

In a centrifugal compressor, an increase in speed at a given pressure ratio causes

Accepted Answer

Increase in flow and decrease in efficiency

Answer

Increase in flow

Answer

Decrease in flow

Answer

Increase in efficiency

Question 5

The clearance volume of the air compressor is kept minimum because

Accepted Answer

It greatly affects volumetric efficiency

Answer

It allows maximum compression to be achieved

Answer

It results in minimum work

Answer

It permits isothermal compression

Question 6

Which is false statement about multistage compression?

Accepted Answer

Volumetric efficiency is high

Answer

Power consumption per unit of air delivered is low

Answer

It is best suited for compression ratios around 7 : 1

Answer

The moisture in air is condensed in the inter-cooler

Question 7

The following is true for an open cycle gas turbine having exhaust heat exchanger. Atmospheric air before entering the compressor is

Accepted Answer

Compressed air before entering the combustion chamber is heated

Answer

Heated

Answer

Bled gas from turbine is heated and readmitted for complete expansion

Answer

Exhaust gases drive the compressor

Question 8

If the flow of air through the compressor is parallel to its axis, then the compressor is

Accepted Answer

Axial flow compressor

Answer

Reciprocating compressor

Answer

Centrifugal compressor

Answer

Turbo compressor

Question 9

Surging is the phenomenon of

Accepted Answer

Unsteady, periodic and reversed flow

Answer

Air stream blocking the passage

Answer

Motion of air at sonic velocity

Answer

Air stream not able to follow the blade contour