Gas Turbines and Jet Engines Online Test2

Thank you very much for taking test

Test your caliber

1. The maximum compression ratio in an actual single stage axial flow comperssor is of the order of _____.
1 : 1.2	1 : 2
1 : 5	1 : 10

2. Maximum delivery pressure is a rotary air compressor is of the order of ______.
6 kg/cm2	10 kg/cm2
16 kg/cm2	25 kg/cm2

3. Surging is the phenomenon of ______.
air stream blocking the passage	motion of air at sonic velocity
unsteady, periodic and reversed flow	air stream not able to follow the blade contour

4. Pick up wrong statement. Surging phenomenon in centrifugal com-pressor depends on
mass flow rate	pressure ratio
change in load	stagnation pressure at the outlet

5. The ratio of the increase in pressure in rotor blades to total increase in pressure in the stage is called
pressure ratio	pressure coefficient
degree of reaction	slip factor

6. Axial flow compressor resembles
centrifugal pump	reciprocating pump
turbine	sliding vane compressor

7. Axial flow compressor has the following advantage over centrifugal compressor
larger air handling ability per unit frontal area	higher pressure ratio per stage
aerofoil blades are used	higher average velocities

8. Actual compression curve is
same as isothermal	same as adiabatic
better than isothermal and adiabatic	in between isothermal and adiabatic

9. Atmospheric pressure is 1.03 kg/cm and vapour pressure is 0.03 kg/cm . The air pressure will be _____.
1.03 kg/cm2	1.06 kg/cm2
1.00 kg/cm2	0.53 kg/cm2

10. The pressure ratio of an ideal vaned compressor with increase in mass flow rate
increases	decreases
remains constant	first decreases and then increases

11. Rotary compressors are suitable for ______.
large discharge at high pressure	low discharge at high pressure
large discharge at low pressure	low discharge at low pressure

12. The vloumetric efficiency of compressor with increase in compression ratio will
increase	decrease
remain same	may increase/decrease depending on clearance volume

13. Stalling of blades in axial flow compressor is the phenomenon of
air stream blocking the passage	motion of air at sonic velocity
unsteady periodic and reversed flow	air stream not able to follow the blade contour

14. Pick up the wrong statement?
centrifugal compressors deliver practically constant pressure over a con siderable range of capacities	Axial flow compressors have a sub-stantially constant delivery at variable pressures
centrifugal compressors have a wider stable operating range than axial flow compressors	axial flow compressors are bigger in diameter compared to centrifugal type

15. The work ratio of a gas turbine plant is defined as the ratio of ______.
net work output and heat supplied	net work output and work done by turbine
actual heat drop and isentropic heat drop	net work output and isentropic heat drop

16. Gas turbine works on ______.
Brayton or Atkinson cycle	Carnot cycle
Rankine cycle	Erricsson cycle

17. The work ratio of simple gas turbine cycle depends on _____.
pressure ratio	maximum cycle temperature
minimum cycle temperature	all of the above

18. The pressure ratio for an open cycle gas turbine compared to closed cycle gas turbine of same h.p. is
low	high
same	low/high depending on make and type

19. Open cycle gas turbine works on ______.
Brayton or Atkinson cycle	Rankine cycle
Carnot cycle	Erricsson cycle

20. The fuel consumption in gas turbines is accounted for by ______.
lower heating value	higher heating value
heating value	higher calorific value