Compressors, Gas Turbines and Jet Engines MCQs

Question 1

During peak load periods, the best method of controlling compressors is

Accepted Answer

Constant speed unloader

Answer

Start-stop motor

Answer

Relief valve

Answer

Variable speed

Question 2

Inter cooling in compressors

Accepted Answer

Results in saving of power in compressing a given volume to given pressure

Answer

Cools the delivered air

Answer

Is the standard practice for big compressors

Answer

Enables compression in two stages

Question 3

Isothermal compression efficiency can be attained by running the compressor

Accepted Answer

At very slow speed

Answer

At very high speed

Answer

At average speed

Answer

At zero speed

Question 4

Fighter bombers use following type of engine

Accepted Answer

Turbojet

Answer

Turbo-propeller

Answer

Rocket

Answer

Ramjet

Question 5

The process, which causes the air to enter the impeller blades of a centrifugal compressor at ________ velocity (without effecting the mass of air to flow and velocity of flow) is known as prewhirl.

Accepted Answer

Reduced

Answer

Increased

Answer

Zero

Answer

None of these

Question 6

For a two stage compressor, if index of compression for higher stage is greater than index of compression for lower stage, then the optimum pressure as compared to ideal case will

Accepted Answer

Increase

Answer

Decrease

Answer

Remain unaffected

Answer

Other factors control it

Question 7

High air-fuel ratio in gas turbines

Accepted Answer

Reduces exhaust temperature

Answer

Increases power output

Answer

Improves thermal efficiency

Answer

Do not damage turbine blades

Question 8

In the axial flow gas turbine, the work ratio is the ratio of

Accepted Answer

Actual total head temperature drop to the isentropic total head drop from total head inlet to static head outlet

Answer

Compressor work and turbine work

Answer

Output and input

Answer

Actual compressor work and theoretical compressor work

Question 9

Which of the following statement is correct relating to rocket engines?

Accepted Answer

All of the above

Answer

The combustion chamber in a rocket engine is directly analogous to the reservoir of a supersonic wind tunnel

Answer

The stagnation conditions exist at the combustion chamber

Answer

The exit velocities of exhaust gases are much higher than those in jet engine