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4

The Parsons' reaction turbine has

A. Only moving blades

B. Only fixed blades

C. Identical fixed and moving blades

D. Fixed and moving blades of different shape

Correct Answer :

C. Identical fixed and moving blades


Related Questions

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4

Expanding steam to a very low pressure (high vacuum) in steam engines is

A. Desirable

B. Economical

C. Essential

D. Uneconomical

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4

The critical pressure ratio for gases is

A. 0.528

B. 0.546

C. 0.577

D. 0.582

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4

The numbers of fire tubes in a Cochran boiler are

A. 75

B. 115

C. 165

D. 225

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4

A closed vessel made of steel and used for the generation of steam is called a

A. Steam boiler

B. Steam turbine

C. Steam condenser

D. Steam injector

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The process of maintaining the speed of the turbine constant for various load conditions, is known as

A. Bleeding

B. Reheating

C. Governing

D. None of these

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4

The impulse turbine rotor efficiency will have a maximum value of 0.5 cos 2α, where α is the nozzle exit flow angle, if the

A. Blades are equiangular

B. Blade velocity coefficient is unity

C. Blades are equiangular and frictionless

D. Blade solidity is 0.65

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4

Which of the following boiler works on a forced circulation of water?

A. Lamont boiler

B. Benson boiler

C. Loeffler boiler

D. All of these

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4

The draught produced by a steam jet issuing from a nozzle placed in the ash-pit under the fire grate of the furnace is called

A. Induced steam jet draught

B. Chimney draught

C. Forced steam jet draught

D. None of these

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4

During storage, the heating value of coal

A. Increases

B. Decreases

C. Remain constant

D. May increase or decrease depending upon the method of storage

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4

A double acting steam engine with a cylinder diameter of 190 mm and a stroke of 300 mm has a cut-off of 0.35. The expansion ratio for this engine is nearly

A. 1.05

B. 2.86

C. 6.65

D. 10.05

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4

Superheating of steam is done at

A. Constant volume

B. Constant temperature

C. Constant pressure

D. Constant entropy

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4

The Parsons' reaction turbine has

A. Only moving blades

B. Only fixed blades

C. Identical fixed and moving blades

D. Fixed and moving blades of different shape

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4

A nozzle is said to be a divergent 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

In a nozzle, the effect of super-saturation is to

A. Decrease dryness fraction of steam

B. Decrease specific volume of steam

C. Increase the entropy

D. Increase the heat drop

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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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Which of the following statement is correct for a compound steam engine?

A. The cost of the engine, for the same power and economy, is more than that of a simple steam engine.

B. The forces in the working parts are increased as the forces are distributed over more parts.

C. The ratio of expansion is reduced, thus reducing the length of stroke.

D. The temperature range per cylinder is increased, with corresponding increase in condensation.

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The critical pressure ratio for initially superheated steam is __________ as compared to initially dry saturated steam.

A. More

B. Less

C. Same

D. None of these

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4

The principal function of a stop valve is to

A. Control the flow of steam from the boiler to the main pipe and to shut off the steam completely when required

B. Empty the boiler when required and to discharge the mud, scale or sediments which are accumulated at the bottom of the boiler

C. Put off fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit

D. Increase the temperature of saturated steam without raising its pressure

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4

In impulse turbines, when friction is neglected, the relative velocity of steam at outlet tip of the blade is __________ the relative velocity of steam at inlet tip of the blade.

A. Equal to

B. Less than

C. Greater than

D. None of these

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4

Thermal efficiency of well maintained boiler will be of the order

A. 40 %

B. 50 %

C. 75 %

D. 90 %

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4

100% efficiency of a thermal cycle cannot be achieved because of

A. Frictional losses

B. It is not possible to achieve 0°K temperature

C. Leakage

D. Non availability of ideal substance

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4

Thermal equilibrium means that the flow of steam is

A. Isothermal

B. Isentropic

C. Hyperbolic

D. Polytropic

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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 evaporation of 15.653 kg of water per hour from and at 100°C is called

A. Evaporative capacity

B. Factor of evaporation

C. Equivalent evaporation

D. One boiler h.p.

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While steam expands in turbines, theoretically the entropy

A. Remains constant

B. Increases

C. Decreases

D. Behaves unpredictably

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4

In recuperative air preheaters, the heat is transferred

A. From a metal wall from one medium to another

B. From heating an intermediate material and then heating the air from this material

C. By direct mixing,

D. Heat is transferred by bleeding some gases from furnace

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4

Steam turbines are used for

A. Large marine propulsion

B. Electric power generation

C. Direct drive of fans, compressors, pumps

D. All of these

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4

The length of Cornish boiler varies from

A. 2 to 4.5 m

B. 3 to 5 m

C. 5 to 7.5 m

D. 7 to 9 m

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4

Willians line follows the law (where b = A constant representing the shape of the Willians line, a = Another constant i.e. no load consumption per hour, I.P. = Indicated power, and m = Steam consumption per hour)

A. I.P. = a × m + b

B. m = a + b × I.P.

C. I.P. = b × m + a

D. m = (b/I.P.) - a

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4

The effect of friction in the nozzle __________ dryness fraction of steam.

A. Has no effect on

B. Decreases

C. Increases

D. None of these