In jet engines, for the efficient production of large power, fuel is burnt in an atmosphere of :
A. vacuum
B. atmospheric air
C. compressed air
D. oxygen alone
In gas turbines^ high thermal efficiency is obtained in :
A. closed cycle
B. open cycle
C. both of the above
D. closed/open depending
A closed gas turbine in which fuel is burnt directly in the air is not possible because of :
A. high pressure ratio
B. increasing gas temperature
C. high specific volume
D. high friction losses
E. paucity of 02
Water is injected in gas turbine cycle to :
A. control temperature
B. control output of turbine
C. control fire hazards
D. increase efficiency
The closed cycle in gas turbines :
A. provides greater flexibility
B. provides lesser flexibility
C. in never used
D. is used when gas is to be burnt
A gas turbine used in air craft should have :
A. high h.p. and low weight
B. low weight and small frontal area
C. small frontal area and high h.p.
D. high speed and high h.p.
Propulsive efficiency is defined as ratio of :
A. thrust power and fuel energy
B. engine output and propulsive power
C. propulsive power and fuel input
D. thrust power and propulsive power
A rocket engine for the combustion of its fuel :
A. carries its own oxygen
B. uses surrounding air
C. uses compressed atmospheric air
D. does not require oxygen
Which of the following fuels can be used in turbojet engines :
A. liquid hydrogen
B. high speed diesel oil
C. kerosene
D. demethylated spirit
A jet engine works on the principle of conservation of :
A. mass
B. energy
C. flow
D. linear momentum
