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4

If p₁ is the pressure of air entering the L.P, cylinder and p₃ is the pressure of air leaving the H.P. cylinder, then the ratio of cylinder diameters for a single acting, two stage reciprocating compressor with complete intercooling is given by

A. D₁/D₂ = (p₁ p₃)1/2

B. D₁/D₂ = (p₁/p₃)1/4

C. D₁/D₂ = (p₁ p₃)1/4

D. D₁/D₂ = (p₃/p₁)1/4

Correct Answer :

D. D₁/D₂ = (p₃/p₁)1/4


Related Questions

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4

If p₁, is the pressure of air entering the L.P. cylinder and p₂ is the pressure of air leaving the L.P. cylinder (or intercooler pressure), then the ratio of cylinder diameters for a single acting, two stage reciprocating air compressor with complete intercooling is given by (where D₁ = Dia. of L.P. cylinder, and D₂ = Dia. of H.P. cylinder)

A. D₁/D₂ = p₁ p₂

B. D₁/D₂ = p₁/p₂

C. D₁/D₂ = p₂/p₁

D. None of these

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4

Rotary compressor is best suited for

A. Large quantity of air at high pressure

B. Small quantity of air at high pressure

C. Small quantity of air at low pressure

D. Large quantity of air at low pressure

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4

In jet propulsion power unit, the inlet duct of diverging shape is used in order to

A. Collect more air

B. Convert kinetic energy of air into pressure energy

C. Provide robust structure

D. Beautify the shape

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4

The air power of the compressor is also known as

A. Indicated power

B. Brake power

C. Frictional power

D. None of these

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4

Diffuser in a compressor is used to

A. Increase velocity

B. Make the flow streamline

C. Convert pressure energy into kinetic energy

D. Convert kinetic energy into pressure energy

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4

The temperature of air at the beginning of the compression stroke is ________ the atmospheric temperature.

A. Equal to

B. Less than

C. More than

D. None of these

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4

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

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4

The intercooler pressure, for minimum work required, for a two stage reciprocating air compressor, is given by (where p₁ = Intake pressure of air, p₂ = Intercooler pressure, and p₃ = Delivery pressure of air)

A. p₂ = p₁ × p₃

B. p₂ = p₁/p₃

C. p₂ = p₁ × p₂

D. p₂ = p₃/p₁

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4

The compressor performance at higher altitude compared to sea level will be

A. Same

B. Higher

C. Lower

D. Dependent on other factors

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4

There is a certain pressure ratio (optimum) for a gas turbine at which its thermal efficiency is maximum. With increase in turbine temperature, the value of pressure ratio for the peak efficiency would

A. Remain same

B. Decrease

C. Increase

D. None of the above

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4

A simple turbojet engine is basically

A. A propeller system

B. Gas turbine engine equipped with a propulsive nozzle and diffuse

C. Chemical rocket engine

D. Ramjet engine

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4

In a jet propulsion unit, the products of combustion after passing through the gas turbine are discharged into

A. Atmosphere

B. Vacuum

C. Discharge nozzle

D. Back to the compressor

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4

In a single stage, single acting reciprocating air compressor, without clearance, the workdone on the air during isentropic compression is ________ the heat required to raise the temperature of air from T₁ to T₂ at a constant pressure.

A. Equal to

B. Less than

C. Greater than

D. None of these

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4

Work ratio of a gas turbine plant is ratio of

A. Net work output and work done by turbine

B. Net work output and heat supplied

C. Work done by turbine and heat supplied

D. Work done by turbine and net work output

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4

Reheating in a gas turbine

A. Increases the thermal efficiency

B. Increases the compressor work

C. Increases the turbine work

D. Decreases the thermal efficiency

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4

In multistage compressor, the isothermal compression is achieved by

A. Employing intercooler

B. By constantly cooling the cylinder

C. By running compressor at very slow speed

D. By insulating the cylinder

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4

It is not possible to use closed gas turbine cycle in aeronautical engines because

A. It is inefficient

B. It is bulky

C. It requires cooling water for its operation

D. None of the above

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4

Pressure ratio in gas turbines is the ratio of

A. Compressor pressure ratio

B. Highest pressure to exhaust pressure

C. Inlet pressure to exhaust pressure

D. Pressures across the turbine

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4

Water 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°C

D. Partial combustion of coal, eke, anthracite coal or charcoal in a mixed air steam blast

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4

Which is false statement about advantages of multistage compressor in comparison to single stage compressor?

A. Less power requirement

B. Better mechanical balance

C. Less loss of air due to leakage past the cylinder

D. Lower volumetric efficiency

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4

Standard air is the air at ________ and relative humidity of 36 percent.

A. 0.1 bar and 20°C

B. 1 bar and 20°C

C. 0.1 bar and 40°C

D. 1 bar and 40°C

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4

Which of the following plants is smallest and lightest for generating a given amount of power?

A. Gas turbine plant

B. Petrol engine

C. Diesel engine

D. Solar plant

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4

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

A. r -1

B. 1 - r -1

C. 1 - (1/r) -1/

D. 1 - (1/r) /-1

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4

In a single stage, single acting reciprocating air compressor without clearance volume, the workdone is maximum during

A. Isothermal compression

B. Isentropic compression

C. Polytropic compression

D. None of these

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4

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 %

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4

A compressor at high altitudes will require ________ power.

A. Same

B. Less

C. More

D. None of these

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4

The working fluid in a turbine is

A. In two phases

B. In three phases

C. In a single phase

D. In the form of air and water mixture

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4

A closed cycle gas turbine works on

A. Carnot cycle

B. Rankine cycle

C. Ericsson cycle

D. Joule cycle

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4

A turboprop is preferred to turbojet because

A. It has high propulsive efficiency at high speeds

B. It can fly at supersonic speeds

C. It can fly at high elevations

D. It has high power for take off

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4

An aftercooler is used to

A. Remove impurities from air

B. Reduce volume of air

C. Cause moisture and oil vapour to drop out

D. Cool the air