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4

The gas in cooling chamber of a closed cycle gas turbine is cooled at

A. Constant volume

B. Constant temperature

C. Constant pressure

D. None of these

Correct Answer :

C. Constant pressure


Related Questions

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4

The ratio of the volume of free air delivery per stroke to the swept volume of the piston, is known as

A. Compressor efficiency

B. Volumetric efficiency

C. Isothermal efficiency

D. Mechanical efficiency

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4

After-cooler is used to

A. Cool the air

B. Decrease the delivery temperature for ease in handling

C. Cause moisture and oil vapour to drop out

D. Reduce volume

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4

If the clearance ratio for a reciprocating air compressor is 'K', then its volumetric efficiency is given by

A. 1 - k + k (p₁/p₂)1/n

B. 1 + k - k (p₂/p₁)1/n

C. 1 - k + k (p₁/p₂) n- 1/n

D. 1 + k - k (p₂/p₁) n-1/n

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4

In air breathing jet engine, the jet is formed by expanding

A. Highly heated atmospheric air

B. Solids

C. Liquid

D. Plasma

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4

For an irreversible gas turbine cycle, the efficiency and work ratio both depend on

A. Pressure ratio alone

B. Maximum cycle temperature alone

C. Minimum cycle temperature alone

D. Both pressure ratio and maximum cycle temperature

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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

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

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

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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

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

When air is to be compressed at a high pressure, then it is advantageous to use

A. Single stage compression

B. Multistage compression without intercooling

C. Multistage compression with intercooling

D. None of these

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4

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°C

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

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4

Maximum delivery pressure is a rotary air compressor is of the order of

A. 6 kg/cm²

B. 10 kg/cm²

C. 16 kg/cm²

D. 25 kg/cm²

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4

The power available for takeoff and climb in case of turbojet engine as compared to reciprocating engine is

A. Less

B. More

C. Same

D. May be less or more depending on ambient conditions

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4

Adiabatic compression is one in which

A. Temperature during compression remains constant

B. No heat leaves or enters the compressor cylinder during compression

C. Temperature rise follows a linear relationship

D. Work done is maximum

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4

Rotary compressors are suitable for

A. Large discharge at high pressure

B. Low discharge at high pressure

C. Large discharge at low pressure

D. Low discharge at low pressure

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4

The thermodynamic efficiency of rotary compressor is based on

A. Isothermal compression

B. Adiabatic compression

C. Isentropic compression

D. Polytropic compression

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4

Phenomenon of choking in compressor means

A. No flow of air

B. Fixed mass flow rate regardless of pressure ratio

C. Reducing mass flow rate with increase in pressure ratio

D. Increased inclination of chord with air steam

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4

The pressure and temperature conditions of air at the suction of compressor are

A. Atmospheric

B. Slightly more than atmospheric

C. Slightly less than atmospheric

D. Pressure slightly less than atmospheric and temperature slightly more than atmospheric

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4

The ratio of the increase in pressure in rotor blades to total increase in pressure in the stage is called

A. Pressure ratio

B. Pressure coefficient

C. Degree of reaction

D. Slip factor

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4

The volumetric efficiency of compressor with increase in compression ratio will

A. Increase

B. Decrease

C. Remain same

D. May increase or decrease depending on clearance volume

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4

Ratio of indicated H.P. and brake H.P. is known as

A. Mechanical efficiency

B. Volumetric efficiency

C. Isothermal efficiency

D. Adiabatic efficiency

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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

In the cross compounding of the gas turbine plant

A. H.P. compressor is connected to H.P. turbine and L.P. compressor to L.P. turbine

B. H.P. compressor is connected to L.P. turbine and L.P. compressor is connected to H.P. turbine

C. Both the arrangements can be employed

D. All are connected in series

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4

The work ratio of a gas turbine plant is defined as the ratio of

A. Net work output and heat supplied

B. Net work output and work done by turbine

C. Actual heat drop and isentropic heat drop

D. Net work output and isentropic heat drop

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4

Maximum work is done in compressing air when the compression is

A. Isothermal

B. Adiabatic

C. Polytropic

D. None of the above

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4

The ratio of specific weight/h.p. of gas turbine and I.C engines may be typically of the order of

A. 1 : 1

B. 2 : 1

C. 4 : 1

D. 1 : 6

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4

Pick up the wrong statement

A. Large gas turbines employ axial flow compressors

B. Axial flow compressors are more stable than centrifugal type compressors but not as efficient

C. Axial flow compressors have high capacity and efficiency

D. Axial flow compressors have instability region of operation

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4

Separators in compressor installations are located

A. Before intercooler

B. After intercooler

C. After receiver

D. Between after-cooler and air receiver

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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