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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

Correct Answer :

B. 20 atmospheres


Related Questions

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4

The change in internal energy in steam engines equals to

A. Work done during the Rankine cycle

B. Work done during compression

C. Work done during adiabatic expansion

D. Change in enthalpy

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4

Which of the following statement is correct?

A. A fire tube boiler occupies less space than a water tube boiler, for a given power.

B. Steam at a high pressure and in large quantities can be produced with a simple vertical boiler.

C. A simple vertical boiler has one fire tube.

D. All of the above

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4

The rate of discharge through the nozzle __________ when the exit pressure is gradually reduced.

A. Remains same

B. Decreases

C. Increases

D. None of these

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4

In a velocity compounded impulse turbine, when steam flows through the second row of moving blades,

A. Velocity increases

B. Velocity decreases

C. Velocity remains constant

D. Pressure remains constant

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4

The number of flue tubes in Lancashire boiler is

A. Zero

B. One

C. Two

D. Four

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4

The shell diameter of a Locomotive boiler is

A. 1 m

B. 1.5 m

C. 2 m

D. 2.5 m

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4

A safety valve mainly used with locomotive and marine boilers is

A. Lever safety valve

B. Dead weight safety valve

C. High steam and low water safety valve

D. Spring loaded safety valve

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4

In order to reduce the rotor speed of an impulse turbine, the method employed is

A. Velocity compounding

B. Pressure compounding

C. Pressure-velocity compounding

D. All of these

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4

The velocity of steam leaving the nozzle (V) is given by (where K = Nozzle coefficient or nozzle efficiency, and hd = Enthalpy or heat drop during expansion of steam in a nozzle)

A. V = 44.72 hd K

B. V = 44.72 K hd

C. V = 44.72 K hd

D. V = 44.72 K hd

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4

The function of injector used in small capacity boilers is to

A. Create vacuum

B. Inject chemical solution in feed pump

C. Pump water, similar to boiler feed pump

D. Add make up water in the system

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4

The steam temperature with increase in load in case of a boiler fitted with radiation superheater

A. Increases

B. Decreases

C. Remain unaffected

D. First increases and then decreases

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4

Which of the following is a fire tube boiler?

A. Locomotive boiler

B. Babcock and Wilcox boiler

C. Stirling boiler

D. All of the above

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4

In a Parson's turbine stage, blade velocity is 320 m/s at the mean radius and rotor blade exit angle is 30°. For minimum kinetic energy of the steam leaving the stage, the steam velocity at the exit of the rotor will be

A. 160/3 m/s

B. 320/3 m/s

C. 640/3 m/s

D. 640 m/s

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4

The ratio of the workdone on the blades per kg of steam to the total energy supplied per stage per kg of steam is called

A. Blading efficiency

B. Nozzle efficiency

C. Stage efficiency

D. Mechanical efficiency

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4

Presence of moisture in fuel oil would

A. Keep the burner tips cool

B. Aid in proper combustion

C. Because sputtering, possibly extinguishing flame

D. Clean the nozzles

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4

A nozzle is said to be a convergent nozzle

A. When the cross-section of the nozzle increases continuously from entrance to exit

B. When the cross-section of the nozzle decreases continuously from entrance to exit

C. When the cross-section of the nozzle first decreases from entrance to throat and then increases from its throat to exit

D. None of the above

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4

The maximum efficiency of a reaction turbine is

A. 2 sin²α/(1 + sin²α)

B. 2 cos²α/(1 + cos²α)

C. (1 + sin²α)/2 sin²α

D. (1 + cos²α)/2 cos²α

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4

The friction in the nozzle __________ exit velocity of steam.

A. Has no effect on

B. Decreases

C. Increases

D. None of these

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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

The relative efficiency is defined as the

A. Ratio of thermal efficiency to Rankine efficiency

B. Ratio of brake power to the indicated power

C. Ratio of heat equivalent to indicated power to the energy supplied in steam

D. Product of thermal efficiency and Rankine efficiency

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4

Which of the following statement is correct for steam turbines as compared to reciprocating steam engines?

A. A steam turbine develops higher speeds

B. The efficiency of steam turbine is higher

C. The steam consumption is less

D. All of these

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4

Ultimate analysis of fuel is determination of percentage of

A. Carbon, hydrogen, nitrogen, sulphur, moisture

B. Fixed carbon, ash, volatile matter, moisture

C. Higher calorific value

D. Lower calorific value

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4

The ratio of the actual vacuum to the ideal vacuum in a condenser is called

A. Condenser efficiency

B. Vacuum efficiency

C. Nozzle efficiency

D. Boiler efficiency

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4

A device used to put off fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit, is called

A. Blow off cock

B. Stop valve

C. Superheater

D. None of these

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4

In water wall furnace, the heat is transferred to the water walls by

A. Convection

B. Radiation

C. Conduction

D. Radiation and conduction

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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 critical pressure gives the velocity of steam at the throat

A. Equal to the velocity of sound

B. Less than the velocity of sound

C. More than the velocity of sound

D. None of these

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4

The efficiency of a pressure-velocity compounded impulse turbine is __________ as compared to pressure compounded impulse turbine.

A. Same

B. Less

C. More

D. None of these

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4

The density of supersaturated steam is about __________ that of the ordinary saturated vapour at the corresponding pressure.

A. Same as

B. 2 times

C. 4 times

D. 8 times

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4

The aim of a compound steam engine is

A. To reduce the ratio of expansion in each cylinder

B. To reduce the length of stroke

C. To reduce the temperature range in each cylinder

D. All of the above