Compressors, Gas Turbines and Jet Engines MCQs

Question 1

Propulsive efficiency is defined as ratio of

Accepted Answer

Thrust power and propulsive power

Answer

Thrust power and fuel energy

Answer

Engine output and propulsive power

Answer

Propulsive power and fuel input

Question 2

The degree of reaction is usually kept ________ for all types of axial flow compressors.

Accepted Answer

0.5

Answer

0.2

Answer

0.3

Answer

0.4

Question 3

The material commonly used for air craft gas turbine is

Accepted Answer

Timken, Haste alloys

Answer

Stainless steel

Answer

High alloy steel

Answer

Duralumin

Question 4

Which one of the following is the effect of blade shape on performance of a centrifugal compressor?

Accepted Answer

Forward curved blades produce lower pressure ratio

Answer

Backward curved blades has poor efficiency

Answer

Backward curved blades lead to stable performance

Answer

Forward curved blades has higher efficiency

Question 5

Intercooling in gas turbines

Accepted Answer

Increases net output and thermal efficiency both

Answer

Decreases net output but increases thermal efficiency

Answer

Increases net output but decreases thermal efficiency

Answer

Decreases net output and thermal efficiency both

Question 6

The following property is most important for material used for gas turbine blade

Accepted Answer

Creep

Answer

Toughness

Answer

Fatigue

Answer

Corrosion resistance

Question 7

The main purpose of reheating in gas turbine is to

Accepted Answer

Increase power output

Answer

Increase temperature

Answer

Reduce turbine size

Answer

Increase speed

Question 8

In the cross compounding of the gas turbine plant

Accepted Answer

H.P. compressor is connected to L.P. turbine and L.P. compressor is connected to H.P. turbine

Answer

H.P. compressor is connected to H.P. turbine and L.P. compressor to L.P. turbine

Answer

Both the arrangements can be employed

Answer

All are connected in series

Question 9

The advantage of multistage compression over single stage compression is

Accepted Answer

All of the above

Answer

Lower power consumption per unit of air delivered

Answer

Higher volumetric efficiency

Answer

Decreased discharge temperature