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4

Size of boiler tubes is specified by

A. Mean diameter and thickness

B. Inside diameter and thickness

C. Outside diameter and thickness

D. Outside diameter and inside diameter

Correct Answer :

C. Outside diameter and thickness


Related Questions

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4

With increase in load, convection superheater has

A. Drooping characteristic

B. Linear characteristic

C. Rising characteristic

D. Flat characteristic

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4

The radius of a dished head is taken approximately as

A. One fourth

B. Half

C. One

D. Two

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4

The velocity of whirl at outlet for an axial discharge turbine is

A. Minimum

B. Maximum

C. Zero

D. None of these

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4

The critical pressure ratio is given by (where p₁ = Initial pressure of steam, and p₂ = Pressure of steam at throat or critical pressure)

A. p₁. p₂

B. p₁/p₂

C. p₂/p₁

D. p₁ + p₂

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4

The maximum discharge through a chimney occurs when the height of chimney is

A. Infinitely long

B. Around 200 meters

C. Equal to the height of the hot gas column producing draught

D. Outside temperature is very low

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4

The safety valve on boiler drum compared to safety valve on superheater is set at

A. Same value

B. Higher value

C. Lower value

D. Lower/higher depending on steam flow

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4

The fire tubes in a Scotch marine boiler are

A. Horizontal

B. Vertical

C. Inclined

D. None of these

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4

A device used to heat feed water by utilising the heat in me exhaust flue gases before leaving through the chimney, is known as

A. Economiser

B. Fusible plug

C. Superheater

D. Stop valve

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4

The coal requirement per kW hour generation in the thermal power plant is of the order of

A. 0.1 to 0.2 kg

B. 0.2 to 0.4 kg

C. 0.6 to 0.8 kg

D. 1.0 to 1.5 kg

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4

The main object of a boiler trial is

A. To determine the generating capacity of the boiler

B. To determine the thermal efficiency of the boiler when working at a definite pressure

C. To prepare heat balance sheet for the boiler

D. All of the above

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4

Expansion ratio is the ratio of

A. Swept volume to the volume at cut-off

B. Clearance volume to the swept volume

C. Volume at cut-off to the swept volume

D. Swept volume to the clearance volume

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4

When the circulation of water, in a boiler, is by convection currents which are set up during the heating of water, then the boiler is known as

A. Internally fired boiler

B. Externally fired boiler

C. Natural circulation boiler

D. Forced circulation boiler

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4

The nozzle efficiency is the ratio of

A. Workdone on the blades to the energy supplied to the blades

B. Workdone on the blades per kg of steam to the total energy supplied per stage per kg of steam

C. Energy supplied to the blades per kg of steam to the total energy supplied per stage per kg of steam

D. None of the above

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4

In water tube boilers

A. Water passes through the tubes which are surrounded by flames and hot gases

B. The flames and hot gases pass through the tubes which are surrounded by water

C. Forced circulation takes place

D. None of these

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4

Which of the following boiler is best suited to meet the fluctuating demand of steam?

A. Locomotive boiler

B. Lancashire boiler

C. Cornish boiler

D. Babcock and Wilcox boiler

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4

In a boiler, feed water supplied per hour is 205 kg while coal fired per hour is 23 kg. The net enthalpy rise per kg of water is 145 kJ. If the calorific valve of the coal is 2050 kJ/kg, then the boiler efficiency will be

A. 56 %

B. 63 %

C. 74 %

D. 78 %

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4

The effect of bleeding is that

A. It increases the thermodynamic efficiency of the turbine

B. Boiler is supplied with hot water

C. It decreases the power developed by the turbine

D. All of the above

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4

A steam nozzle converts

A. Heat energy of steam into kinetic energy

B. Kinetic energy into heat energy of steam

C. Heat energy of steam into potential energy

D. Potential energy into heat energy of steam

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4

In cross compounding, the cylinders are arranged

A. Side by side and each cylinder has common piston, connecting rod and crank

B. Side by side and each cylinder has separate piston, connecting rod and crank

C. At 90° and each cylinder has common piston, connecting rod and crank

D. At 90° and each cylinder has separate piston, connecting rod and crank

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4

The ratio of brake power to the indicated power is known as

A. Mechanical efficiency

B. Overall efficiency

C. Indicated thermal efficiency

D. Brake thermal efficiency

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4

The high pressure boiler is one, which produces steam at a pressure more than

A. Atmospheric pressure

B. 5 kg/cm²

C. 10 kg/cm²

D. 7580 kg/cm²

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4

The efficiency of the plant __________ with the mechanical draught.

A. Increases

B. Decreases

C. Remains constant

D. None of these

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4

The draught may be produced by a

A. Mechanical fan

B. Chimney

C. A steam jet

D. All of these

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4

In a steam engine, superheated steam from the boiler is fed into the steam chest at a pressure of

A. 10 atmospheres

B. 20 atmospheres

C. 30 atmospheres

D. 40 atmospheres

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4

The compounding of turbines is done in order to

A. Reduce speed of rotor

B. Improve efficiency

C. Reduce exit losses

D. All of these

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4

Primary air is the air used to

A. Provide air around burners for obtaining optimum combustion

B. Transport and dry the coal

C. Convert CO (formed in lower zone of furnace) into CO₂ at higher zone

D. Air delivered by forced draft fan

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4

The pressure compounded impulse turbine as compared to velocity compounded turbine require __________ number of stages.

A. Same

B. Less

C. More

D. None of these

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4

Sulphur content of fuels is very important to the plant operators because it

A. Has high heating value

B. Retards electric precipitation

C. Promotes complete combustion

D. Has highly corrosive effect

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4

A wet vapour can be completely specified by

A. Pressure only

B. Temperature only

C. Dryness fraction only

D. Pressure and dryness fraction

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4

Which of the following boilers is best suited to meet fluctuating demands?

A. Babcock and Wilcox

B. Locomotive

C. Lancashire

D. Cochran