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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

Correct Answer :

D. All of these


Related Questions

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4

A _________ in a boiler is used to put off fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit.

A. Blow off cock

B. Fusible plug

C. Stop valve

D. Safety valve

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4

For a Parson's reaction turbine, if α₁ and α₂ are fixed blade angles at inlet and exit respectively and β₁ and β₂ are the moving blade angles at entrance and exit respectively, then

A. α₁ = α₂ and β₁ = β₂

B. α₁ = β₁ and α₂= β₂

C. α₁ < β₁ and α₂ > β₂

D. α₁ = β₂ and β₁ = α₂

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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

In a Tandem type compound engine, the high pressure and low pressure cylinders

A. Have common piston rod

B. Are set at 90°

C. Have separate piston rods

D. Are set in V-arrangement

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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

Secondary 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 induced draft fan

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4

With increase in load, radiant superheater has

A. Drooping characteristic

B. Linear characteristic

C. Rising characteristic

D. Flat characteristic

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4

When the cross-section of a nozzle __________ continuously from entrance to exit, it is called a convergent nozzle.

A. Increases

B. Decreases

C. Remain same

D. None of these

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4

For the same length of stroke and speed of crankshaft, the piston speed for a double acting steam engine is _________ the piston speed of single acting steam engine.

A. Equal to

B. Twice

C. Three times

D. Four times

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4

The action of steam in a steam turbine is

A. Static

B. Dynamic

C. Static and dynamic

D. Neither static nor dynamic

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4

The actual power supplied by the engine crankshaft is called

A. Indicated power

B. Brake power

C. Frictional power

D. None of these

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4

In an impulse turbine

A. The steam is expanded in nozzles only and there is a pressure drop and heat drop

B. The steam is expanded both in fixed and moving blades continuously

C. The steam is expanded in moving blades only

D. The pressure and temperature of steam remains constant

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4

The size of a boiler drum in pulverised fuel fired boiler, as its size and capacity, (steam pressure and flow ratings) increase

A. Increases

B. Decreases

C. Remains unchanged

D. Increases/decreases depending on steam temperature requirements

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4

A turbine is said to have an axial discharge when the steam leaves the blade tip at _________ to the direction of the blade motion.

A. 60°

B. 90°

C. 180°

D. 270°

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4

The ratio of the isentropic heat drop to the heat supplied, is called

A. Reheat factor

B. Stage efficiency

C. Internal efficiency

D. Rankine efficiency

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4

Mechanical equivalent of heat for 1 kcal or Joule's equivalent is equal to

A. 421 kg.m

B. 421 kg.m

C. 539 kg.m

D. 102 kg.m

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4

In an experiment to determine dryness fraction of steam, the mass of water separated was 1.2 kg in 15 mts. and the mass of steam passed out in same time was 4.8 kg. Dryness fraction is

A. 40 %

B. 25 %

C. 50 %

D. 80 %

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4

The critical pressure ratio (p₂/p₁) is given by

A. (p₂/p₁) = [2/(n - 1)] n/(n + 1)

B. (p₂/p₁) = [2/(n + 1)] n/(n-1)

C. (p₂/p₁) = [(n - 1)/2] n + (1/n)

D. (p₂/p₁) = [(n + 1)/2] n - (1/n)

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4

The purpose of governing in steam turbines is to

A. Maintain the speed of the turbine

B. Reduce the effective heat drop

C. Reheat the steam and improve its quality

D. Completely balance against end thrust

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4

The effect of super-saturation is that the

A. Mass of the steam discharged increases

B. Entropy and specific volume of the steam increases

C. Exit velocity of steam reduces

D. All of these

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4

At very low temperature, the melting and boiling temperatures become equal. This temperature is

A. 373°K

B. 273.16°K

C. 303°K

D. 0°K

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4

The major axis of elliptical manholes on the shell should be provided

A. Longitudinally

B. Circumferentially

C. On dished end

D. Anywhere

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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

It is required to produce large amount of steam at low pressure. Which boiler should be used?

A. Pulverised fuel fired boiler

B. Cochran boiler

C. Lancashire boiler

D. Babcock and Wilcox boiler

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4

The velocity of flue gases (V) through the chimney under a static draught of (H') metres is given by

A. V = 2g H'

B. V = 2g/H'

C. V = H'/2g

D. V = 2gH'

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4

The performance of a boiler is measured by the

A. Amount of water evaporated per hour

B. Steam produced in kg/h

C. Steam produced in kg/kg of fuel burnt

D. All of these

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4

Equivalent evaporation is the amount of water evaporated in a boiler from and at

A. 0°C

B. 100°C

C. Saturation temperature at given pressure

D. Room temperature

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4

Which of the following is not a boiler mounting?

A. Blow off cock

B. Feed check valve

C. Economiser

D. Fusible plug

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4

The temperature of flue gases at air heater outlet should be

A. 100°C

B. Above dew point temperature of flue gases

C. Below dew point temperature of flue gases

D. Less than wet bulb temperature of flue gases

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4

The pressure of reheat steam after passing through reheater compared to inlet condition is

A. More

B. Less

C. Equal

D. May be more or less depending on capacity of reheater