back pressure
critical pressure
discharge pressure
none of these
✅ The correct answer is option C.
Compressors, Gas Dynamics and Gas Turbines MCQs
2. 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.
reduced
increased
✅ The correct answer is option A.
3. The workdone on a compressor will be minimum if air is taken from
the atmosphere
a source at 0° C
a source of low temperature air
a source of high tempe
✅ The correct answer is option C.
4. In air compressors, free air delivery means the
actual volume of the air delivered by the compressor when reduced to normal temperature and pressure conditions
volume of air delivered by the compressor
volume of air sucked by the compressor during its suction stroke
none of the above
✅ The correct answer is option A.
5. If the flow of air through the compressor is perpendicular to its axis, then it is a
reciprocating compressor
centrifugal compressor
axial flow compressor
turbo compressor
✅ The correct answer is option B.
6. In open cycle turbo-jet engines used in military aircraft, reheating the exhaust gas from the turbine by burning, more fuel is used to increase the
thrust and range of aircraft
efficiency of the engine
both (a) and (b)
none of these
✅ The correct answer is option A.
7. In a single acting reciprocating air compressor, without clearance, the compression of air may be
isothermal
polytropic
isentropic
any one of these
✅ The correct answer is option D.
8. A turbo-prop is preferred to turbo-jet because
it has high propulsive efficiency at high speeds
it can fly at super sonic speeds
it can fly at high elevations
it has high power for
✅ The correct answer is option D.
9. A closed cycle gas turbine works on
Carnot cycle
Rankine cycle
Ericsson cycle
Joule cycle
✅ The correct answer is option D.
10. The efficiency of roots blower __________ with the increase in pressure ratio.
decreases
increases
does not change
✅ The correct answer is option A.