A 3 m3/min compressor means that it

delivers 3 m3/ min of compressed air

compresses 3 m3/min of standard air

compresses 3 m3/ min of free air

delivers 3 m3/ min of compressed air

delivers 3 m3/ min of compressed air at delivery pressure

Axial flow compressor has the following advantage over centrifugal compressor:

Higher pressure ratio per stage

Larger air handling ability per unit frontal area

Higher pressure ratio per stage

Following points express the effect of keeping high clearance volume for the cylinders in reciprocating compressor. Which one of following points is disagreeable?

By increasing clearance volume chances of piston striking cylinder head gets reduced

By increasing clearance volume volumetric efficiency decrease

By increasing clearance volume power consumption increases

By increasing clearance volume chances of piston striking cylinder head gets reduced

By increasing clearance volume maximum compression pressure value decreases.

For a two-stage compressor, the ratio of diameters of L.P cylinder to H.P cylinder is equal to:

Cube root of the ratio of final pressure to initial pressure

Square of the ratio of final pressure to initial pressure

The ratio of final pressure to initial pressure

The square root of the ratio of final pressure to initial pressure

Cube root of the ratio of final pressure to initial pressure

For a two-stage reciprocating air compressor, for minimum work required the intercooler pressure is given by

\({P_2} = \;{P_1} \times {P_3}\)

\({P_2} = \sqrt {{P_1} \times {P_3}} \)

\({P_2} = \;{P_1} \times {P_3}\)

\({P_2} = \frac{1}{{\sqrt {{P_1} \times {P_3}} }}\)

\({P_2} = \frac{1}{{\left( {{P_1} \times {P_3}} \right)}}\)

For maximum efficiency in multi-stage compressor

Air should be cooled to initial temperature between the stages

Pressure ratio for each stage should be same

Work done for each stage should be same

For minimum compression work in a 2 - stage reciprocating air compressor, which of the following expressions gives the ratio of low pressure cylinder to high pressure cylinder diameters?Where P1 P2 and P3 are suction, intermediate and delivery pressures respectively.

\({\left( {\frac{{{P_3}}}{{{P_2}}}} \right)^{\frac{1}{4}}}\)

\({\left( {\frac{{{P_3}}}{{{P_1}}}} \right)^{\frac{1}{4}}}\)

\({\left( {\frac{{{P_3}}}{{{P_1}}}} \right)^{\frac{1}{3}}}\)

\({\left( {\frac{{{P_3}}}{{{P_1}}}} \right)^{\frac{1}{2}}}\)

\({\left( {\frac{{{P_3}}}{{{P_2}}}} \right)^{\frac{1}{4}}}\)

Identify the incorrect statement, from the following options. In a multi-stage reciprocating compressor, the process of intercooling ________.

Reduces the compression work needed

Final compressed air delivery pressure is higher as compared to single compression

Reduces the compression work needed

Cools the compressed air from each stage before admission to the next stage

Is used during compression of air in two or more stages

For reciprocating air compressor, the law of compression desired is isothermal and that may be possible at

any speed as speed does not affect the compression law

For minimum work in compressor operating between limits P1 and P3 the intercooler P2 is given by

\({P_2} = \sqrt {{P_1} + {P_3}}\)

\({P_2} = \sqrt {{P_1} - {P_3}}\)

\({P_2} = \sqrt {{P_1}{P_3}} \)

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

\({P_2} = {P_a}\sqrt {\frac{{{P_3}}}{{{P_1}}}} \)

\({P_2} = \frac{{{P_1} + {P_3}}}{2}\)

\({P_2} = \sqrt {{P_1} \cdot {P_3}} \)

\({P_2} = {P_a}\sqrt {\frac{{{P_3}}}{{{P_1}}}} \)

\({P_2} = {P_a}\sqrt {\frac{{{P_1}}}{{{P_3}}}} \)

In pressure compounded turbine

pressure remain uniform throughout

pressure drop in each stage is equal

pressure increases as steam flows over blades

most of the kinetic energy of steam is absorbed as it passes over moving blades

pressure remain uniform throughout

Assertion (A) : The volumetric efficiency of Reciprocating Compressor (with clearance) is always less than 100%. Reason (R) : The air present in the clearance volume will expand before the intake conditions are reached and it occupies some volume of cylinder.

Both (A) and (It) are true and (R) is true reason for

Both (A) and (R) arc true and (R) is not the correct explanation for (A)

Both (A) and (It) are true and (R) is true reason for

An after-cooler provided in reciprocating compressors performs the function of _____.

removal of moisture from compressed air

reducing temperature of compressed air

removal of moisture from compressed air

removal of impurities from compressed air

reducing the volume of compressed air

In case of reciprocating compressors, irreversibility is due to which of the following reasons

Due to flow of refrigerant at low velocity

Due to pressure rise across valves

Due to pressure drop and heat transfer

219 + Mcqs in Compressors Gas Dynamics and Gas Turbines in Automobile Engineering Page 1 McqOptions

1.	The propulsive power of the rocket is (where v1 = Jet velocity, and v2 = Air-craft velocity)
A.	[A].
B.	[B].
C.	[C].
D.	[D].
Answer» B. [B].

Discussion

2.	In n1 and n2 are the indices of compression for the first and second stage of compression, then the ratio of workdone on the first and second stages (W1/W2) with perfect intercoooing is given by
A.	[A].
B.	[B].
C.	[C].
D.	[D].
Answer» C. [C].

Discussion

3.	A 3 m3/min compressor means that it
A.	compresses 3 m3/min of standard air
B.	compresses 3 m3/ min of free air
C.	delivers 3 m3/ min of compressed air
D.	delivers 3 m3/ min of compressed air at delivery pressure
Answer» C. delivers 3 m3/ min of compressed air

Discussion

4.	In centrifugal compressors, there exists a loss of energy due to the mismatch of direction of relative velocity of fluid at inlet with inlet blade angle. This loss is known as
A.	frictional loss
B.	incidence loss
C.	clearance loss
D.	leakage loss
Answer» C. clearance loss

Discussion

5.	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

6.	Cooling of reciprocating compressor cylinder:1) Increases the volumetric efficiency2) Increases the work input3) Decreases the volumetric efficiency4) Decreases the work inputWhich of the above statements are correct?
A.	1 and 2
B.	2 and 3
C.	3 and 4
D.	1 and 4
Answer» E.

Discussion

7.	Consider the following statements about two-stage reciprocating compressors:1. For the same pressure ratio the volumetric efficiency of a two-stage compressor is more than that of single stage compressor.2. A two-stage compressor requires minimum work when inter-cooling is perfect.3. The intercooler pressure p2, is the average of inlet pressure p1, and delivery pressure p3Which of the above statements are correct?
A.	1 and 3 only
B.	1 and 2 only
C.	2 and 3 only
D.	1, 2 and 3
Answer» C. 2 and 3 only

Discussion

8.	In a two stage reciprocating air compressor with a suction pressure of 4 bar and delivery pressure of 16 bar, the ideal intercooler pressure will be
A.	10 bar
B.	8 bar
C.	32 bar
D.	20 bar
Answer» C. 32 bar

Discussion

9.	An air compressor compresses atmospheric air at 0.1 MPa and 27°C by 10 times of air inlet pressure. During compression, the heat lost to the surrounding is estimated to be 5% of compression work. Air enters the compressor with a velocity of 40 m/s and leaves with 100 m/s. The inlet and exit cross-sectional areas are 100 cm2 and 20 cm2 respectively. The temperature of air at the exit from the compressor will be
A.	1498 K
B.	1574 K
C.	1654 K
D.	1726 K
Answer» B. 1574 K

Discussion

10.	Following points express the effect of keeping high clearance volume for the cylinders in reciprocating compressor. Which one of following points is disagreeable?
A.	By increasing clearance volume volumetric efficiency decrease
B.	By increasing clearance volume power consumption increases
C.	By increasing clearance volume chances of piston striking cylinder head gets reduced
D.	By increasing clearance volume maximum compression pressure value decreases.
Answer» C. By increasing clearance volume chances of piston striking cylinder head gets reduced

Discussion

11.	A centrifugal compressor develops a pressure ratio of 5 and air consumption of 30 kg/s. The inlet temperature and pressure are 15°C and 1 bar respectively. For an isentropic efficiency of 0.85, the power required by the compressor will be nearly
A.	5964 kW
B.	5778 kW
C.	5586 kW
D.	5397 kW
Answer» B. 5778 kW

Discussion

12.	In a two-stage reciprocating air compressor, the suction and delivery pressures are 1 and 4 bar respectively. For maximum efficiency, the intercooler pressure is
A.	1.5 bar
B.	2 bar
C.	2.5 bar
D.	3 bar
Answer» C. 2.5 bar

Discussion

13.	For a two-stage compressor, the ratio of diameters of L.P cylinder to H.P cylinder is equal to:
A.	Square of the ratio of final pressure to initial pressure
B.	The ratio of final pressure to initial pressure
C.	The square root of the ratio of final pressure to initial pressure
D.	Cube root of the ratio of final pressure to initial pressure
Answer» D. Cube root of the ratio of final pressure to initial pressure

Discussion

14.	In a two-stage reciprocating air-compressor with suction pressure of 2 bar and delivery pressure of 8 bar, the ideal intercooler pressure will be
A.	10 bar
B.	6 bar
C.	4 bar
D.	3 bar
Answer» D. 3 bar

Discussion

15.	In high-speed compressors, _______ bearings are used.
A.	bronze
B.	precision insert
C.	sleeve type
D.	copper
Answer» C. sleeve type

Discussion

16.	A gas turbine plant working on Joule cycle produces 4000 kW of power. If its work ratio is 40%, what is the power consumed by the compressor in (kW)
A.	6000
B.	4000
C.	160
D.	1000
Answer» B. 4000

Discussion

17.	A two stage centrifugal compressor operating at 3000 rpm is to compress refrigerant R134a from an evaporator temperature of 0°C (hi = 398.6 kJ/kg) to a condensing temperature of 32°C (he = 419.8 kJ/kg). If the impeller diameter of both the stages have to be same, what is the diameter of the impeller?Assume suction condition to be dry saturated, compression process isentropic, impeller blades radial and refrigerant enters impeller radially
A.	0.65 m
B.	0.8 m
C.	1.0 m
D.	1.5 m
Answer» B. 0.8 m

Discussion

18.	At the eye tip of a centrifugal impeller, blade velocity is 200 m/s while the uniform axial velocity at the inlet is 150 m/s. If the sonic velocity is 300 m/s, then the inlet Mach number of flow will be
A.	0.75
B.	0.66
C.	0.9
D.	0.83
Answer» E.

Discussion

19.	For a two-stage reciprocating air compressor, for minimum work required the intercooler pressure is given by
A.	\({P_2} = \sqrt {{P_1} \times {P_3}} \)
B.	\({P_2} = \;{P_1} \times {P_3}\)
C.	\({P_2} = \frac{1}{{\sqrt {{P_1} \times {P_3}} }}\)
D.	\({P_2} = \frac{1}{{\left( {{P_1} \times {P_3}} \right)}}\)
Answer» B. \({P_2} = \;{P_1} \times {P_3}\)

Discussion

20.	Compressor capacity is expressed in
A.	m3/kg
B.	kW
C.	kWh
D.	m3/min
Answer» E.

Discussion

21.	A large clearance volume in reciprocating compressor results in
A.	Reduced volume flow rate
B.	Increased volume flow rate
C.	Lower suction pressure
D.	Lower delivery pressure
Answer» B. Increased volume flow rate

Discussion

22.	For maximum efficiency in multi-stage compressor
A.	Air should be cooled to initial temperature between the stages
B.	Pressure ratio for each stage should be same
C.	Work done for each stage should be same
D.	All of the above
Answer» E.

Discussion

23.	For maximum efficiency, the intermediate pressure, P2, in 2-stage reciprocating compressor should be
A.	\(\frac{P_1~ +~ P_3}{2}\)
B.	\(\frac{P_3~-~P_1}{2}\)
C.	\(\sqrt{P_1\times P_3}\)
D.	None of these
Answer» D. None of these

Discussion

24.	If suction, compression and delivery of the air takes place on one side of the piston only then the compressor is known as:
A.	multistage
B.	single acting
C.	single stage
D.	double acting
Answer» C. single stage

Discussion

25.	In a reciprocating compressor, the clearance ratio is generally between:
A.	10% and 30%
B.	8% and 20%
C.	5% and 12%
D.	4% and 10%
Answer» E.

Discussion

26.	______ valves are provided in reciprocating compressors.
A.	Simply Supported
B.	Plate
C.	Poppet
D.	Solenoid
Answer» C. Poppet

Discussion

27.	For minimum compression work in a 2 - stage reciprocating air compressor, which of the following expressions gives the ratio of low pressure cylinder to high pressure cylinder diameters?Where P1 P2 and P3 are suction, intermediate and delivery pressures respectively.
A.	\({\left( {\frac{{{P_3}}}{{{P_1}}}} \right)^{\frac{1}{4}}}\)
B.	\({\left( {\frac{{{P_3}}}{{{P_1}}}} \right)^{\frac{1}{3}}}\)
C.	\({\left( {\frac{{{P_3}}}{{{P_1}}}} \right)^{\frac{1}{2}}}\)
D.	\({\left( {\frac{{{P_3}}}{{{P_2}}}} \right)^{\frac{1}{4}}}\)
Answer» D. \({\left( {\frac{{{P_3}}}{{{P_2}}}} \right)^{\frac{1}{4}}}\)

Discussion

28.	Identify the incorrect statement, from the following options. In a multi-stage reciprocating compressor, the process of intercooling ________.
A.	Final compressed air delivery pressure is higher as compared to single compression
B.	Reduces the compression work needed
C.	Cools the compressed air from each stage before admission to the next stage
D.	Is used during compression of air in two or more stages
Answer» B. Reduces the compression work needed

Discussion

29.	Circulating water around the cylinder, which helps the air to cool during compression, is called:
A.	water jacketing
B.	pack jacketing
C.	flow jacketing
D.	oil jacketing
Answer» B. pack jacketing

Discussion

30.	In a P-V diagram of a steady flow compressor, the intercooling can be represented as
A.	Vertical line
B.	Horizontal line
C.	Parabolic line
D.	None of the above
Answer» C. Parabolic line

Discussion

31.	A compressor delivers 4 m3 of air having a mass of 5 kg. The specific weight and specific volume of air being delivered will be nearly
A.	12.3 N/m3 and 0.8 m3/kg
B.	14.6 N/m3 and 0.4 m3/kg
C.	12.3 N/m3 and 0.4 m3/kg
D.	14.6 N/m3 and 0.8 m3/kg
Answer» B. 14.6 N/m3 and 0.4 m3/kg

Discussion

32.	For reciprocating air compressor, the law of compression desired is isothermal and that may be possible at
A.	very low speeds
B.	very high speeds
C.	any speed as speed does not affect the compression law
D.	None of the above
Answer» B. very high speeds

Discussion

33.	In actual compressors, there is a clearance between the cylinder head and piston to take care of thermal expansion. Identify the correct expression from the given options, where C is the clearance (in mm) and L is the stoke length (in mm).
A.	C = (0.005L + 0.05)
B.	C = (0.005 + 0.5L)
C.	C = (0.005L + 0.5)
D.	C = (0.05L + 0.5)
Answer» D. C = (0.05L + 0.5)

Discussion

34.	For minimum work in compressor operating between limits P1 and P3 the intercooler P2 is given by
A.	\({P_2} = \sqrt {{P_1} + {P_3}}\)
B.	\({P_2} = \sqrt {{P_1} - {P_3}}\)
C.	\({P_2} = \sqrt {{P_1}{P_3}} \)
D.	P2 = P1 + P3
Answer» D. P2 = P1 + P3

Discussion

35.	Consider the following statements:1) Stalling is the separation of flow from the blade surface.2) Surging leads to physical damage due to impact loads and high-frequency vibration.3) Mass flow rate is minimum if choking occurs.Which of the above statements are correct?
A.	1, 2 and 3
B.	1 and 3 only
C.	1 and 2 only
D.	2 and 3 only
Answer» D. 2 and 3 only

Discussion

36.	Air is compressed in a single stage reciprocating compressor at the rate of 1 kg/s from 1 bar at 22°C to 8 bar. If γ = 1.4 and R = 287 J/kgK for air, also take (8)0.286 = 1.81 and ln(8) = 2.079. Difference in work required in compression was isentropic and isothermal:
A.	240.45 kW
B.	218.32 kW
C.	176.06 kW
D.	64.39 kW
Answer» E.

Discussion

37.	Air is compressed entropically in a single stage single acting compressor from an initial condition of 1 bar and 30°C to 5 bar. If γ = 1.4 and R = 287 J/kg.K for air, work of compression for unit mass rate of air is (Use (5)0.286 = 1.584)
A.	198.3 kW
B.	17.769 kW
C.	177.69 kW
D.	205.8 kW
Answer» D. 205.8 kW

Discussion

38.	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
A.	\({P_2} = \frac{{{P_1} + {P_3}}}{2}\)
B.	\({P_2} = \sqrt {{P_1} \cdot {P_3}} \)
C.	\({P_2} = {P_a}\sqrt {\frac{{{P_3}}}{{{P_1}}}} \)
D.	\({P_2} = {P_a}\sqrt {\frac{{{P_1}}}{{{P_3}}}} \)
Answer» C. \({P_2} = {P_a}\sqrt {\frac{{{P_3}}}{{{P_1}}}} \)

Discussion

39.	In Reciprocating air compressor the method of controlling the quantity of air delivered is done by
A.	throttle control
B.	blow-off control
C.	clearance control
D.	all the above
Answer» E.

Discussion

40.	In pressure compounded turbine
A.	pressure drop in each stage is equal
B.	pressure increases as steam flows over blades
C.	most of the kinetic energy of steam is absorbed as it passes over moving blades
D.	pressure remain uniform throughout
Answer» D. pressure remain uniform throughout

Discussion

41.	An airplane is flying at an height of 14 km where temperature is -45°C. The speed of the plane is corresponding to M = 2. Find the speed of the plane if R = 287 J/kg-K and Ƴ = 1.4.
A.	2179 km/h
B.	3010 km/h
C.	3250 km/h
D.	3379 km/h
Answer» B. 3010 km/h

Discussion

42.	If the compression of air is carried out in a large number of stages with perfect intercooling between the stages, then the overall compression approaches an:
A.	isochoric process
B.	isenthalpic process
C.	isentropic process
D.	isothermal process
Answer» E.

Discussion

43.	Assertion (A) : The volumetric efficiency of Reciprocating Compressor (with clearance) is always less than 100%. Reason (R) : The air present in the clearance volume will expand before the intake conditions are reached and it occupies some volume of cylinder.
A.	Both (A) and (R) arc true and (R) is not the correct explanation for (A)
B.	Both (A) and (It) are true and (R) is true reason for
C.	(A) is true, but (It) is false
D.	Both (A) and (R) are false
Answer» B. Both (A) and (It) are true and (R) is true reason for

Discussion

44.	If compressor air flow is parallel to its axis then the compressor is called
A.	Turbo compressor
B.	Axial flow compressor
C.	Reciprocating compressor
D.	Centrifugal compressor
Answer» C. Reciprocating compressor

Discussion

45.	In the following diagram, for axial flow compressors, surging is likely to occur in
A.	4th zone
B.	2nd zone
C.	1st zone
D.	3rd zone
Answer» D. 3rd zone

Discussion

46.	An after-cooler provided in reciprocating compressors performs the function of _____.
A.	reducing temperature of compressed air
B.	removal of moisture from compressed air
C.	removal of impurities from compressed air
D.	reducing the volume of compressed air
Answer» B. removal of moisture from compressed air

Discussion

47.	In case of reciprocating compressors, irreversibility is due to which of the following reasons
A.	Due to flow of refrigerant at low velocity
B.	Due to pressure rise across valves
C.	Only due to heat transfer
D.	Due to pressure drop and heat transfer
Answer» E.

Discussion

48.	Flow coefficient in axial compressor is defined as-______. (Axial velocity of flow = vf, Blade velocity at periphery = u)
A.	\(\frac{{{v_f}}}{u}\)
B.	\(\frac{u}{{{v_f}}}\)
C.	\(\frac{{{v_f} + u}}{u}\)
D.	\(\frac{{{u^2}}}{{{v_f}}}\)
Answer» B. \(\frac{u}{{{v_f}}}\)

Discussion

49.	In a two-stage reciprocating compressor, the suction pressure is 1.5 bar and delivery pressure is 54 bar with a perfect intercooler. If both stages follow the same polytropic process, the intermediate pressure will be equal to
A.	6 bar
B.	9 bar
C.	27.75 bar
D.	\(\frac{1}{\sqrt2}\)bar
Answer» C. 27.75 bar

Discussion

50.	For a multistage reciprocating compressor; which of the following statements are correct?1. It decreases volumetric efficiency2. The work of compression is reduced3. The high pressure cylinder is smaller in size
A.	1 and 2 only
B.	2 and 3 only
C.	1 and 3 only
D.	1,2 and 3
Answer» C. 1 and 3 only

Discussion

Explore topic-wise MCQs in Automobile Engineering.

The propulsive power of the rocket is (where v1 = Jet velocity, and v2 = Air-craft velocity)

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A 3 m3/min compressor means that it

In centrifugal compressors, there exists a loss of energy due to the mismatch of direction of relative velocity of fluid at inlet with inlet blade angle. This loss is known as

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Following points express the effect of keeping high clearance volume for the cylinders in reciprocating compressor. Which one of following points is disagreeable?

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In a two-stage reciprocating air compressor, the suction and delivery pressures are 1 and 4 bar respectively. For maximum efficiency, the intercooler pressure is

For a two-stage compressor, the ratio of diameters of L.P cylinder to H.P cylinder is equal to:

In a two-stage reciprocating air-compressor with suction pressure of 2 bar and delivery pressure of 8 bar, the ideal intercooler pressure will be

In high-speed compressors, _______ bearings are used.

A gas turbine plant working on Joule cycle produces 4000 kW of power. If its work ratio is 40%, what is the power consumed by the compressor in (kW)

At the eye tip of a centrifugal impeller, blade velocity is 200 m/s while the uniform axial velocity at the inlet is 150 m/s. If the sonic velocity is 300 m/s, then the inlet Mach number of flow will be

For a two-stage reciprocating air compressor, for minimum work required the intercooler pressure is given by

Compressor capacity is expressed in

A large clearance volume in reciprocating compressor results in

For maximum efficiency in multi-stage compressor

For maximum efficiency, the intermediate pressure, P2, in 2-stage reciprocating compressor should be

If suction, compression and delivery of the air takes place on one side of the piston only then the compressor is known as:

In a reciprocating compressor, the clearance ratio is generally between:

______ valves are provided in reciprocating compressors.

For minimum compression work in a 2 - stage reciprocating air compressor, which of the following expressions gives the ratio of low pressure cylinder to high pressure cylinder diameters?Where P1 P2 and P3 are suction, intermediate and delivery pressures respectively.

Identify the incorrect statement, from the following options. In a multi-stage reciprocating compressor, the process of intercooling ________.

Circulating water around the cylinder, which helps the air to cool during compression, is called:

In a P-V diagram of a steady flow compressor, the intercooling can be represented as

A compressor delivers 4 m3 of air having a mass of 5 kg. The specific weight and specific volume of air being delivered will be nearly

For reciprocating air compressor, the law of compression desired is isothermal and that may be possible at

In actual compressors, there is a clearance between the cylinder head and piston to take care of thermal expansion. Identify the correct expression from the given options, where C is the clearance (in mm) and L is the stoke length (in mm).

For minimum work in compressor operating between limits P1 and P3 the intercooler P2 is given by

Consider the following statements:1) Stalling is the separation of flow from the blade surface.2) Surging leads to physical damage due to impact loads and high-frequency vibration.3) Mass flow rate is minimum if choking occurs.Which of the above statements are correct?

Air is compressed in a single stage reciprocating compressor at the rate of 1 kg/s from 1 bar at 22°C to 8 bar. If γ = 1.4 and R = 287 J/kgK for air, also take (8)0.286 = 1.81 and ln(8) = 2.079. Difference in work required in compression was isentropic and isothermal:

Air is compressed entropically in a single stage single acting compressor from an initial condition of 1 bar and 30°C to 5 bar. If γ = 1.4 and R = 287 J/kg.K for air, work of compression for unit mass rate of air is (Use (5)0.286 = 1.584)

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

In Reciprocating air compressor the method of controlling the quantity of air delivered is done by

In pressure compounded turbine

An airplane is flying at an height of 14 km where temperature is -45°C. The speed of the plane is corresponding to M = 2. Find the speed of the plane if R = 287 J/kg-K and Ƴ = 1.4.

If the compression of air is carried out in a large number of stages with perfect intercooling between the stages, then the overall compression approaches an:

Assertion (A) : The volumetric efficiency of Reciprocating Compressor (with clearance) is always less than 100%. Reason (R) : The air present in the clearance volume will expand before the intake conditions are reached and it occupies some volume of cylinder.

If compressor air flow is parallel to its axis then the compressor is called

In the following diagram, for axial flow compressors, surging is likely to occur in

An after-cooler provided in reciprocating compressors performs the function of _____.

In case of reciprocating compressors, irreversibility is due to which of the following reasons

Flow coefficient in axial compressor is defined as-______. (Axial velocity of flow = vf, Blade velocity at periphery = u)

In a two-stage reciprocating compressor, the suction pressure is 1.5 bar and delivery pressure is 54 bar with a perfect intercooler. If both stages follow the same polytropic process, the intermediate pressure will be equal to

For a multistage reciprocating compressor; which of the following statements are correct?1. It decreases volumetric efficiency2. The work of compression is reduced3. The high pressure cylinder is smaller in size