454 + Mcqs in Compressors, Gas Turbines And Jet Engines McqOptions

1.	/_The volumetric efficiency for reciprocating air compressors is about?
A.	10 to 40%
B.	40 to 60%
C.	60 to 70%
D.	70 to 90%
Answer» E.

Discussion

2.	/_The blades of gas turbine are made of?
A.	High nickel alloy
B.	Stainless steel
C.	Carbon steel
D.	High alloy steel
Answer» B. Stainless steel

Discussion

3.	/_The type of rotary compressor used in gas turbines, is of?
A.	Centrifugal type
B.	Axial flow type
C.	Radial flow type
D.	None of these
Answer» C. Radial flow type

Discussion

4.	/_Clearance volume in actual reciprocating compressors is essential?
A.	To accommodate Valves in the cylinder head
B.	To provide cushioning effect
C.	To attain high volumetric efficiency
D.	To provide cushioning effect and also to avoid mechanical bang of piston with cylinder head
Answer» E.

Discussion

5.	/_Volumetric efficiency of air compressors is of the order of?
A.	20 - 30%
B.	40 - 50%
C.	60 - 70%
D.	70 - 90%
Answer» E.

Discussion

6.	/_Euler's equation is applicable for?
A.	Centrifugal compressor
B.	Axial compressor
C.	Pumps
D.	All of the above
Answer» E.

Discussion

7.	/_The most efficient method of compressing air is to compress it?
A.	Isothermally
B.	Adiabatically
C.	Isentropically
D.	Isochronically
Answer» B. Adiabatically

Discussion

8.	/_Axial flow compressor has the following advantage over centrifugal compressor?
A.	Larger air handling ability per unit frontal area
B.	Higher pressure ratio per stage
C.	Aerofoil blades are used
D.	Higher average velocities
Answer» B. Higher pressure ratio per stage

Discussion

9.	/_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
Answer» B. Carbon dioxide

Discussion

10.	/_Euler's equation can be used for?
A.	Radial flow compressors
B.	Axial flow compressors
C.	Pumps
D.	All of these
Answer» E.

Discussion

11.	/_In a centrifugal compressor, the ratio of the ________ to the blade velocity is called slip factor.?
A.	Inlet whirl velocity
B.	Outlet whirl velocity
C.	Inlet velocity of flow
D.	Outlet velocity of flow
Answer» E.

Discussion

12.	/_With the decrease in compression ratio, the volumetric efficiency?
A.	Does not change
B.	Increases
C.	Decreases
D.	First decrease and then increase
Answer» C. Decreases

Discussion

13.	/_Gas turbines use following type of air compressor?
A.	Centrifugal type
B.	Reciprocating type
C.	Lobe type
D.	Axial flow type
Answer» E.

Discussion

14.	/_For a two stage compressor, if index of compression for higher stage is greater than index of compression for lower stage, then the optimum pressure as compared to ideal case will?
A.	Increase
B.	Decrease
C.	Remain unaffected
D.	Other factors control it
Answer» B. Decrease

Discussion

15.	/_During peak load periods, the best method of controlling compressors is?
A.	Start-stop motor
B.	Constant speed unloader
C.	Relief valve
D.	Variable speed
Answer» C. Relief valve

Discussion

16.	/_The thrust on the rotor in a centrifugal compressor is produced by?
A.	Radial component
B.	Axial component
C.	Tangential component
D.	None of the above
Answer» C. Tangential component

Discussion

17.	/_Volumetric efficiency of a compressor decreases with ________ in compression ratio.?
A.	Decrease
B.	Increase
C.	Remain same
D.	Does not change
Answer» C. Remain same

Discussion

18.	/_Maximum work is done in compressing air when the compression is?
A.	Isothermal
B.	Adiabatic
C.	Polytropic
D.	None of the above
Answer» C. Polytropic

Discussion

19.	/_Gas turbine works on?
A.	Brayton or Atkinson cycle
B.	Carnot cycle
C.	Rankine cycle
D.	Ericsson cycle
Answer» B. Carnot cycle

Discussion

20.	/_The inter-cooler pressure, for minimum work required, for a two stage reciprocating air compressor, is given by (where p‚Äö√á√Ö = Intake pressure of air, p‚Äö√á√á = Inter-cooler pressure, and p‚Äö√á√â = Delivery pressure of air)?
A.	p‚Äö√á√á = p‚Äö√á√Ö ‚àö√≥ p‚Äö√á√â
B.	p‚Äö√á√á = p‚Äö√á√Ö/p‚Äö√á√â
C.	p‚Äö√á√á = p‚Äö√á√Ö ‚àö√≥ p‚Äö√á√á
D.	p‚Äö√á√á = p‚Äö√á√â/p‚Äö√á√Ö
Answer» D. p‚Äö√á√á = p‚Äö√á√â/p‚Äö√á√Ö

Discussion

21.	/_The volume of air sucked by the compressor during its suction stroke is called?
A.	Free air delivery
B.	Compressor capacity
C.	Swept volume
D.	None of these
Answer» D. None of these

Discussion

22.	/_In a jet engine, the air-fuel ratio is?
A.	30:1
B.	40:1
C.	50:1
D.	60:1
Answer» E.

Discussion

23.	/_Gas turbine cycle with regenerator?
A.	Increases thermal efficiency
B.	Allows high compression ratio
C.	Decreases heat loss is exhaust
D.	Allows operation at very high altitudes
Answer» B. Allows high compression ratio

Discussion

24.	/_The overall thermal efficiency of an ideal gas turbine plant is (where r = Pressure ratio)?
A.	r ‚Ä¶¬£-1
B.	1 - r ‚Ä¶¬£-1
C.	1 - (1/r) ‚Ä¶¬£-1/‚Ä¶¬£
D.	1 - (1/r) ‚Ä¶¬£/‚Ä¶¬£-1
Answer» D. 1 - (1/r) ‚Ä¶¬£/‚Ä¶¬£-1

Discussion

25.	/_Isothermal compression though most efficient, but is not practicable because?
A.	It requires very big cylinder
B.	It does not increase pressure much
C.	It is impossible in practice
D.	Compressor has to run at very slow speed to achieve it
Answer» E.

Discussion

26.	/_In a double acting compressor, the air is compressed?
A.	In one cylinder
B.	In two cylinders
C.	In a single cylinder on both sides of the piston
D.	In two cylinders on both sides of the piston
Answer» D. In two cylinders on both sides of the piston

Discussion

27.	/_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
Answer» D. Oxygen alone

Discussion

28.	/_Ratio of indicated H.P. and brake H.P. is known as?
A.	Mechanical efficiency
B.	Volumetric efficiency
C.	Isothermal efficiency
D.	Adiabatic efficiency
Answer» B. Volumetric efficiency

Discussion

29.	/_To avoid moisture troubles, the compressed air main line should?
A.	Rise gradually towards the point of use
B.	Drop gradually towards the point of use
C.	Be laid vertically
D.	Be laid exactly horizontally
Answer» C. Be laid vertically

Discussion

30.	/_The net work input required for compressor with increase in clearance volume?
A.	Increases
B.	Decreases
C.	Remains same
D.	Increases/decreases depending on compressor capacity
Answer» D. Increases/decreases depending on compressor capacity

Discussion

31.	/_Reheating in a multistage expansion gas turbine ________ compressor work.?
A.	Has no effect on
B.	Decreases
C.	Increases
D.	None of these
Answer» C. Increases

Discussion

32.	/_The ratio of outlet whirl velocity to blade velocity in case of centrifugal compressor is called?
A.	Slip factor
B.	Velocity factor
C.	Velocity coefficient
D.	None of the above
Answer» B. Velocity factor

Discussion

33.	/_Reheating in gas turbine results in?
A.	Increase of work ratio
B.	Decrease of thermal efficiency
C.	Decrease of work ratio
D.	Both (A) and (B) above
Answer» E.

Discussion

34.	/_Producer gas is produced by?
A.	Carbonisation of coal
B.	Passing steam over incandescent coke
C.	Passing air and a large amount of steam over waste coal at about 65¬¨‚àûC
D.	Partial combustion of coal, coke, anthracite coal or charcoal in a mixed air steam blast
Answer» E.

Discussion

35.	/_The advantage of multistage compression over single stage compression is?
A.	Lower power consumption per unit of air delivered
B.	Higher volumetric efficiency
C.	Decreased discharge temperature
D.	All of the above
Answer» E.

Discussion

36.	/_The maximum temperature in a gas turbine is?
A.	200¬¨‚àûC
B.	500¬¨‚àûC
C.	700¬¨‚àûC
D.	1000¬¨‚àûC
Answer» D. 1000¬¨‚àûC

Discussion

37.	%_In a jet engine, the air-fuel ratio is_%
A.	30:1
B.	40:1
C.	50:1
D.	60:1
Answer» E.

Discussion

38.	%_In a double acting compressor, the air is compressed_%
A.	In one cylinder
B.	In two cylinders
C.	In a single cylinder on both sides of the piston
D.	In two cylinders on both sides of the piston
Answer» D. In two cylinders on both sides of the piston

Discussion

39.	%_Isothermal compression though most efficient, but is not practicable because_%
A.	It requires very big cylinder
B.	It does not increase pressure much
C.	It is impossible in practice
D.	Compressor has to run at very slow speed to achieve it
Answer» E.

Discussion

40.	%_To avoid moisture troubles, the compressed air main line should_%
A.	Rise gradually towards the point of use
B.	Drop gradually towards the point of use
C.	Be laid vertically
D.	Be laid exactly horizontally
Answer» C. Be laid vertically

Discussion

41.	%_The inter-cooler pressure, for minimum work required, for a two stage reciprocating air compressor, is given by (where p‚Äö√á√Ö = Intake pressure of air, p‚Äö√á√á = Inter-cooler pressure, and p‚Äö√á√â = Delivery pressure of air)_%
A.	p‚Äö√á√á = p‚Äö√á√Ö ‚àö√≥ p‚Äö√á√â
B.	p‚Äö√á√á = p‚Äö√á√Ö/p‚Äö√á√â
C.	p‚Äö√á√á = p‚Äö√á√Ö ‚àö√≥ p‚Äö√á√á
D.	p‚Äö√á√á = p‚Äö√á√â/p‚Äö√á√Ö
Answer» D. p‚Äö√á√á = p‚Äö√á√â/p‚Äö√á√Ö

Discussion

42.	%_Reheating in a multistage expansion gas turbine ________ compressor work._%
A.	Has no effect on
B.	Decreases
C.	Increases
D.	None of these
Answer» C. Increases

Discussion

43.	%_Ratio of indicated H.P. and brake H.P. is known as_%
A.	Mechanical efficiency
B.	Volumetric efficiency
C.	Isothermal efficiency
D.	Adiabatic efficiency
Answer» B. Volumetric efficiency

Discussion

44.	%_The volume of air sucked by the compressor during its suction stroke is called_%
A.	Free air delivery
B.	Compressor capacity
C.	Swept volume
D.	None of these
Answer» D. None of these

Discussion

45.	%_Gas turbine works on_%
A.	Brayton or Atkinson cycle
B.	Carnot cycle
C.	Rankine cycle
D.	Ericsson cycle
Answer» B. Carnot cycle

Discussion

46.	%_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
Answer» D. Oxygen alone

Discussion

47.	%_The net work input required for compressor with increase in clearance volume_%
A.	Increases
B.	Decreases
C.	Remains same
D.	Increases/decreases depending on compressor capacity
Answer» D. Increases/decreases depending on compressor capacity

Discussion

48.	_ Which of the following statement is correct as regard to centrifugal compressors?$?
A.	The flow of air is parallel to the axis of the compressor
B.	The static pressure of air in the impeller increases in order to provide centripetal force on the air
C.	The impeller rotates at high speeds
D.	The maximum efficiency is higher than multistage axial flow compressors
Answer» C. The impeller rotates at high speeds

Discussion

49.	_ If the flow of air through the compressor is parallel to its axis, then the compressor is$?
A.	Reciprocating compressor
B.	Centrifugal compressor
C.	Axial flow compressor
D.	Turbo compressor
Answer» D. Turbo compressor

Discussion

50.	_ Mechanical efficiency of gas turbines as compared to I.C engines is$?
A.	Higher
B.	Lower
C.	Same
D.	None of the above
Answer» B. Lower

Discussion

Explore topic-wise MCQs in Testing Subject.

*/*_The volumetric efficiency for reciprocating air compressors is about?

*/*_The blades of gas turbine are made of?

*/*_The type of rotary compressor used in gas turbines, is of?

*/*_Clearance volume in actual reciprocating compressors is essential?

*/*_Volumetric efficiency of air compressors is of the order of?

*/*_Euler's equation is applicable for?

*/*_The most efficient method of compressing air is to compress it?

*/*_Axial flow compressor has the following advantage over centrifugal compressor?

*/*_The effective power of gas turbines is increased by adding the following in compressor?

*/*_Euler's equation can be used for?

*/*_In a centrifugal compressor, the ratio of the ________ to the blade velocity is called slip factor.?

*/*_With the decrease in compression ratio, the volumetric efficiency?

*/*_Gas turbines use following type of air compressor?

*/*_For a two stage compressor, if index of compression for higher stage is greater than index of compression for lower stage, then the optimum pressure as compared to ideal case will?

*/*_During peak load periods, the best method of controlling compressors is?

*/*_The thrust on the rotor in a centrifugal compressor is produced by?

*/*_Volumetric efficiency of a compressor decreases with ________ in compression ratio.?

*/*_Maximum work is done in compressing air when the compression is?

*/*_Gas turbine works on?

*/*_The inter-cooler pressure, for minimum work required, for a two stage reciprocating air compressor, is given by (where p‚Äö√á√Ö = Intake pressure of air, p‚Äö√á√á = Inter-cooler pressure, and p‚Äö√á√â = Delivery pressure of air)?

*/*_The volume of air sucked by the compressor during its suction stroke is called?

*/*_In a jet engine, the air-fuel ratio is?

*/*_Gas turbine cycle with regenerator?

*/*_The overall thermal efficiency of an ideal gas turbine plant is (where r = Pressure ratio)?

*/*_Isothermal compression though most efficient, but is not practicable because?

*/*_In a double acting compressor, the air is compressed?

*/*_In jet engines, for the efficient production of large power, fuel is burnt in an atmosphere of?

*/*_Ratio of indicated H.P. and brake H.P. is known as?

*/*_To avoid moisture troubles, the compressed air main line should?

*/*_The net work input required for compressor with increase in clearance volume?

*/*_Reheating in a multistage expansion gas turbine ________ compressor work.?

*/*_The ratio of outlet whirl velocity to blade velocity in case of centrifugal compressor is called?

*/*_Reheating in gas turbine results in?

*/*_Producer gas is produced by?

*/*_The advantage of multistage compression over single stage compression is?

*/*_The maximum temperature in a gas turbine is?

%_In a jet engine, the air-fuel ratio is_%

%_In a double acting compressor, the air is compressed_%

%_Isothermal compression though most efficient, but is not practicable because_%

%_To avoid moisture troubles, the compressed air main line should_%

%_The inter-cooler pressure, for minimum work required, for a two stage reciprocating air compressor, is given by (where p‚Äö√á√Ö = Intake pressure of air, p‚Äö√á√á = Inter-cooler pressure, and p‚Äö√á√â = Delivery pressure of air)_%

%_Reheating in a multistage expansion gas turbine ________ compressor work._%

%_Ratio of indicated H.P. and brake H.P. is known as_%

%_The volume of air sucked by the compressor during its suction stroke is called_%

%_Gas turbine works on_%

%_In jet engines, for the efficient production of large power, fuel is burnt in an atmosphere of_%

%_The net work input required for compressor with increase in clearance volume_%

_ Which of the following statement is correct as regard to centrifugal compressors?$?

_ If the flow of air through the compressor is parallel to its axis, then the compressor is$?

_ Mechanical efficiency of gas turbines as compared to I.C engines is$?

/_The volumetric efficiency for reciprocating air compressors is about?

/_The blades of gas turbine are made of?

/_The type of rotary compressor used in gas turbines, is of?

/_Clearance volume in actual reciprocating compressors is essential?

/_Volumetric efficiency of air compressors is of the order of?

/_Euler's equation is applicable for?

/_The most efficient method of compressing air is to compress it?

/_Axial flow compressor has the following advantage over centrifugal compressor?

/_The effective power of gas turbines is increased by adding the following in compressor?

/_Euler's equation can be used for?

/_In a centrifugal compressor, the ratio of the ________ to the blade velocity is called slip factor.?

/_With the decrease in compression ratio, the volumetric efficiency?

/_Gas turbines use following type of air compressor?

/_For a two stage compressor, if index of compression for higher stage is greater than index of compression for lower stage, then the optimum pressure as compared to ideal case will?

/_During peak load periods, the best method of controlling compressors is?

/_The thrust on the rotor in a centrifugal compressor is produced by?

/_Volumetric efficiency of a compressor decreases with ________ in compression ratio.?

/_Maximum work is done in compressing air when the compression is?

/_Gas turbine works on?

/_The inter-cooler pressure, for minimum work required, for a two stage reciprocating air compressor, is given by (where p‚Äö√á√Ö = Intake pressure of air, p‚Äö√á√á = Inter-cooler pressure, and p‚Äö√á√â = Delivery pressure of air)?

/_The volume of air sucked by the compressor during its suction stroke is called?

/_In a jet engine, the air-fuel ratio is?

/_Gas turbine cycle with regenerator?

/_The overall thermal efficiency of an ideal gas turbine plant is (where r = Pressure ratio)?

/_Isothermal compression though most efficient, but is not practicable because?

/_In a double acting compressor, the air is compressed?

/_In jet engines, for the efficient production of large power, fuel is burnt in an atmosphere of?

/_Ratio of indicated H.P. and brake H.P. is known as?

/_To avoid moisture troubles, the compressed air main line should?

/_The net work input required for compressor with increase in clearance volume?

/_Reheating in a multistage expansion gas turbine ________ compressor work.?

/_The ratio of outlet whirl velocity to blade velocity in case of centrifugal compressor is called?

/_Reheating in gas turbine results in?

/_Producer gas is produced by?

/_The advantage of multistage compression over single stage compression is?

/_The maximum temperature in a gas turbine is?