High air-fuel ratio is used in gas turbines______________________?
(A) to increase the output
(B) to increase the efficiency
(C) to save fuel
(D) to reduce the exit temperature
(D) none of the above
In jet engines the compression ratio__________________?
(A) varies as square root of the speed
(B) Varies linearly to the speed
(C) varies as square of the speed
(D) varies as cube of the speed
(D) is constant irrespective of variation in speed
Air-fuel ratio in a jet engine will be of the order of__________________?
(A) 10: 1
(B) 15: 1
(C) 20 : 1
(D) 60 : 1
(D) 100 :
The effective power of gas turbines is increased by adding the following in compressor__________________?
(A) ammonia and water vapour
(B) carbon dioxide
(C) nitrogen
(D) hydrogen
(D) none of the above
The specific output per kg mass flow rate of a gas turbine (having fixed efficiencies of compressor and turine and fixed higher and lower temperature) with increase in pressure ratio will___________________?
(A) increase first at fast rate and then slow
(B) increase first at slow rate and then fast
(C) decrease continuously
(D) first increase, reach maximum and then decrease
(D) none of the above
Turbofan engine employs ____________________ ?
(A) one air stream
(B) two or more air streams
(C) no air stream
(D) solid fuel firing
(D) rocket principle for its operation
The efficiency and work ratio of a gas turbine plant can be increased by _____________________?
(A) using mulit-stage compressor with mfercooler
(B) adding heat exchanger
(C) injecting water in/around combustion chamber
(D) reheating the air after partial expansion in the turbine
(D) all of the above
The compression ratio in a jet engine varies proportional to ____________________?
(A) speed
(B) speed
(C) altitude
(D) Vspeed
(D) does not Vary
For speed above 3000 km/hour, it is more advantageous to use____________________?
(A) turbo-jet engine
(B) ram-jet engine
(C) propellers
(D) rockets
(D) hydraulic jet propulsion
The efficiency of jet engine is__________________?
(A) higher at ground
(B) higher at high altitudes
(C) same at all altitudes
(D) higher at high speed
(D) lower at low speed