For maximum work, the reheating should be done to an intermediate pressure of1 = Maximum pressure and p2 = Minimum pressure)
A. 2 p 1 − p 2
B. 2 p 1 + p 2
C. p 2 p 1
D. p 1 p 2
Select an option to see the answer and solution.
Inter-cooling in multistage compressors is done
A. To cool the air during compression
B. To cool the air at delivery
C. To enable compression in two stages
D. To minimize the work of compression
Select an option to see the answer and solution.
The efficiency and work ratio of a gas turbine plant can be increased by
A. Adding heat exchanger
B. Injecting water in/around combustion chamber
C. Reheating the air after partial expansion in the turbine
D. All of the above
Select an option to see the answer and solution.
The thrust of a jet propulsion power unit can be increased by
A. Injecting water into the compressor
B. Burning fuel after gas turbine
C. Injecting ammonia into the combustion chamber
D. All of the above
Select an option to see the answer and solution.
Euler's equation can be used for
A. Radial flow compressors
B. Axial flow compressors
C. Pumps
D. All of these
Select an option to see the answer and solution.
Adiabatic compression is one in which
A. Temperature during compression remains constant
B. No heat leaves or enters the compressor cylinder during compression
C. Temperature rise follows a linear relationship
D. Work done is maximum
Select an option to see the answer and solution.
Ratio of compression is the ratio of
A. Gauge discharge pressure to the gauge intake pressure
B. Absolute discharge pressure to the absolute intake pressure
C. Pressures at discharge and suction corresponding to same temperature
D. Stroke volume and clearance volume
Select an option to see the answer and solution.
The work done per unit mass of air in compression will be least when 'n' is equal to
Select an option to see the answer and solution.
The efficiency of roots blower ________ with the increase in pressure ratio.
A. Decreases
B. Increases
C. Does not change
D. None of these
Select an option to see the answer and solution.
During peak load periods, the best method of controlling compressors is
A. Start-stop motor
B. Constant speed unloader
C. Relief valve
D. Variable speed
Select an option to see the answer and solution.
Inter cooling in compressors
A. Cools the delivered air
B. Results in saving of power in compressing a given volume to given pressure
C. Is the standard practice for big compressors
D. Enables compression in two stages
Select an option to see the answer and solution.
Isothermal compression efficiency can be attained by running the compressor
A. At very high speed
B. At very slow speed
C. At average speed
D. At zero speed
Select an option to see the answer and solution.
Fighter bombers use following type of engine
A. Turbojet
B. Turbo-propeller
C. Rocket
D. Ramjet
Select an option to see the answer and solution.
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.
A. Reduced
B. Increased
C. Zero
D. None of these
Select an option to see the answer and solution.
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
A. Increase
B. Decrease
C. Remain unaffected
D. Other factors control it
Select an option to see the answer and solution.
High air-fuel ratio in gas turbines
A. Increases power output
B. Improves thermal efficiency
C. Reduces exhaust temperature
D. Do not damage turbine blades
Select an option to see the answer and solution.
In the axial flow gas turbine, the work ratio is the ratio of
A. Compressor work and turbine work
B. Output and input
C. Actual total head temperature drop to the isentropic total head drop from total head inlet to static head outlet
D. Actual compressor work and theoretical compressor work
Select an option to see the answer and solution.
Which of the following statement is correct relating to rocket engines?
A. The combustion chamber in a rocket engine is directly analogous to the reservoir of a supersonic wind tunnel
B. The stagnation conditions exist at the combustion chamber
C. The exit velocities of exhaust gases are much higher than those in jet engine
D. All of the above
Select an option to see the answer and solution.
The power available for takeoff and climb in case of turbojet engine as compared to reciprocating engine is
A. Less
B. More
C. Same
D. May be less or more depending on ambient conditions
Select an option to see the answer and solution.
Gas turbines use following type of air compressor
A. Centrifugal type
B. Reciprocating type
C. Lobe type
D. Axial flow type
Select an option to see the answer and solution.
