Q.1
When the temperature of air leaving the intercooler, in a two stage compression with intercooler, is __________ the original atmospheric air temperature, then the intercooling is known as perfect or complete intercooling.
  • equal to
  • less than
  • more than
Q.2
Intercooling in gas turbines
  • decreases net output but increases thermal efficiency
  • increases net output but decreases thermal efficiency
  • decreases net output and thermal efficiency both
  • increases net output and thermal efficiency both
Q.3
A closed cycle gas turbine gives __________ efficiency as compared to an open cycle gas turbine.
  • same
  • lower
  • higher
Q.4
A large clearance Volume in a reciprocating compressor results in
  • reduced volume flow rate
  • increased volume flow rate
  • lower suction pressure
  • lower delivery pressure
Q.5
In a centrifugal compressor, an increase in speed at a given pressure ratio causes
  • increase in flow
  • decrease in flow
  • increase in efficiency
  • increase in flow and decrease in efficiency
Q.6
A rotary compressor is driven by an
  • electric motor
  • engine
  • either (a) or (b)
  • none of these
Q.7
Workdone by a two-stage reciprocating air compressor per cycle is equal to the workdone in LP. cylinder and H.P. cylinder.
  • True
  • False
Q.8
Rotary compressors are used for delivering
  • small quantities of air at high pressures
  • large quantities of air at high pressures
  • small quantities of air at low pressures
  • large quantities of air at low pressures
Q.9
The efficiency of a jet engine is higher at
  • low speeds
  • high speeds
  • low altitudes
  • high altitudes
Q.10
The type of rotary compressor used in gas turbines, is of
  • centrifugal type
  • axial flow type
  • radial flow type
  • none of these
Q.11
In the aircraft propellers
  • the propulsive matter is ejected from within the propelled body
  • the propulsive matter is caused to flow around the propelled body
  • its functioning does not depend upon the presence of air
  • none of the above
Q.12
For a two stage reciprocating compressor, compression from p1 to p3 is with perfect intercooling and no pressure losses. If compression in both the cylinders follows the same polytropic process and the atmospheric pressure is pa, then the intermediate pressure p2 is given by
  • p2 = (p1 + p3)/2
  • p2 = p1.p3
  • P2 = Pa x p3/p1
  • p2 = pa p3/p1
Q.13
The inlet pressure is always __________ the discharge pressure.
  • equal to
  • less than
  • more than
Q.14
The clearance volume in the compressor is kept minimum because it effects on volumetric efficiency.
  • Correct
  • Incorrect
Q.15
The ratio of workdone per cycle to the stroke volume of the compressor is known as
  • compressor capacity
  • compression ratio
  • compressor efficiency
  • mean effective pressure
Q.16
Intercooling in multi-stage compressors is done
  • to cool the air during compression
  • to cool the air at delivery
  • to enable compression in two stages
  • to minimise the work of compression
Q.17
The capacity of a compressor is expressed in
  • kg/m2
  • kg/m3
  • m3/min
  • m3/kg
Q.18
The increase in pressure in a vane blower takes place first due to compression and then due to back flow of air.
  • Correct
  • Incorrect
Q.19
An open cycle gas turbine works on the same cycle as that of a closed cycle gas turbine.
  • Yes
  • No
Q.20
The total heat rejected in a reciprocating air compressor is equal to the sum of the heat rejected during polytropic compression per kg of air and heat rejected in the intercooler per kg of air.
  • True
  • False
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