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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

Correct Answer :

C. p₂ = p₁ × p₂


Related Questions

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4

The overall isothermal efficiency of the compressor is defined as the ratio of

A. Work required to compress the air isothermally to the actual work required to compress the air for the same pressure ratio

B. Isothermal power to the shaft power or B.P. of the motor or engine required to drive the compressor

C. Volume of free air delivery per stroke to the swept volume of the piston

D. Isentropic power to the power required to drive the compressor

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4

A rocket engine uses ________ for the combustion of its fuel.

A. Surrounding air

B. Compressed atmospheric air

C. Its own oxygen

D. None of these

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4

The capacity of compressor will be highest when its intake temperature is

A. Lowest

B. Highest

C. Anything

D. Atmospheric

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4

The clearance volume of the air compressor is kept minimum because

A. It allows maximum compression to be achieved

B. It greatly affects volumetric efficiency

C. It results in minimum work

D. It permits isothermal compression

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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

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

A. Equal to

B. Less than

C. More than

D. None of these

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4

The following is true for an open cycle gas turbine having exhaust heat exchanger. Atmospheric air before entering the compressor is

A. Heated

B. Compressed air before entering the combustion chamber is heated

C. Bled gas from turbine is heated and readmitted for complete expansion

D. Exhaust gases drive the compressor

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4

Fighter bombers use following type of engine

A. Turbojet

B. Turbo-propeller

C. Rocket

D. Ramjet

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4

Which is false statement about air receivers?

A. These are used to dampen pulsations

B. These act as reservoir to take care of sudden demands

C. These increase compressor efficiency

D. These knock out some oil and moisture

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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

Propulsion efficiency of the following order is obtained in practice

A. 34 %

B. 50 %

C. 60 %

D. 72 %

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4

The compressor efficiency is the

A. Isothermal H.P/indicated H.R

B. Isothermal H.P./shaft H.R

C. Total output/air input

D. Compression work/motor input

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4

Inter cooling in compressors

A. Cools the delivered air

B. Results in saving of power in compressing a given volume to given pressure

C. Is the standard practice for big compressors

D. Enables compression in two stages

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4

The capacity of a compressor is expressed in

A. kg/m²

B. kg/m³

C. m³/min

D. m³/kg

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4

The mass of gas turbine per kW developed is about ________ as that of an I.C. engine.

A. Same

B. One-half

C. One fourth

D. One sixth

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4

The maximum temperature in a gas turbine is

A. 200°C

B. 500°C

C. 700°C

D. 1000°C

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4

The degree of reaction of an axial flow turbine is the ratio of isentropic temperature drop in a blade row to the

A. Adiabatic temperature drop in the stage

B. Total temperature drop

C. Total temperature drop in the stage

D. Total adiabatic temperature drop

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4

Inter-cooling in gas turbine results in

A. Increase in net output but decrease in thermal efficiency

B. Increase in thermal efficiency but decrease in net output

C. Increase in both thermal efficiency and net output

D. Decrease in both thermal efficiency and net output

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4

The following property is most important for material used for gas turbine blade

A. Toughness

B. Fatigue

C. Creep

D. Corrosion resistance

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4

The output of a gas turbine is 300 KW and its efficiency is 20 percent, the heat supplied is

A. 6000 KW

B. 15 KW

C. 600 KW

D. 150 KW

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4

In jet engines, paraffin is usually used as the fuel because of its

A. High calorific value

B. Ease of atomisation

C. Low freezing point

D. Both (A) and (C) above

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4

The maximum delivery pressure in a rotary air compressor is

A. 10 bar

B. 20 bar

C. 30 bar

D. 50 bar

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4

The work done per unit mass of air in compression will be least when n is equal to

A. 1

B. 1.2

C. 1.3

D. 1.4

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4

The blades of gas turbine are made of

A. High nickel alloy

B. Stainless steel

C. Carbon steel

D. High alloy steel

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4

Axial flow compressor resembles

A. Centrifugal pump

B. Reciprocating pump

C. Turbine

D. Sliding vane compressor

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4

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

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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

1 m of air at atmospheric condition weighs approximately

A. 0.5 kg

B. 1.0 kg

C. 1.3 kg

D. 2.2 kg

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4

If V, U and Vr represent the absolute velocity of fluid, velocity of blade, and relative velocity of fluid, and suffix I and o stand for entry and exit conditions, then in a rotary machine whose degree of reaction is unity

A. Vi = Vo

B. Vt > Vo

C. U < Vo

D. V = Uo

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4

Aeroplanes employ following type of compressor

A. Radial flow

B. Axial flow

C. Centrifugal

D. None of the above