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4

By fitting an air vessel to the reciprocating pump, there is always a saving of work done and subsequently saving of power. The saving in case of a double acting reciprocating pump is

A. 39.2 %

B. 48.8 %

C. 84.8 %

D. 88.4 %

Correct Answer :

A. 39.2 %


Related Questions

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4

Which of the following statement is correct?

A. In an impulse turbine, the water impinges on the buckets with pressure energy.

B. In a reaction turbine, the water glides over the moving vanes with kinetic energy.

C. In an impulse turbine, the pressure of the flowing water remains unchanged and is equal to atmospheric pressure.

D. In a reaction turbine, the pressure of the flowing water increases after gliding over the vanes.

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4

Any change in load is adjusted by adjusting following parameter on turbine

A. Net head

B. Absolute velocity

C. Blade velocity

D. Flow

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4

Air vessels in reciprocating pump are used to

A. Smoothen flow

B. Reduce acceleration to minimum

C. Increase pump efficiency

D. Save pump from cavitations

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4

Which of the following pump is successfully used for lifting water to the turbines?

A. Centrifugal pump

B. Reciprocating pump

C. Jet pump

D. Air lift pump

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4

A Pelton wheel develops 1750 kW under a head of 100 metres while running at 200 r.p.m. and discharging 2500 litres of water per second. The unit discharge of wheel is

A. 0.25 m3/s

B. 0.5 m3/s

C. 1.5 m3/s

D. 2.5 m3/s

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4

A Pelton wheel working under a constant head and discharge, has maximum efficiency when the speed ratio is

A. 0.26

B. 0.36

C. 0.46

D. 0.56

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4

The unit discharge through the turbine is

A. Q/√H

B. Q/H

C. Q/H3/2

D. Q/H²

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4

When a piping system is made up primarily of vertical lift and very little pipe friction, the pump characteristics should be

A. Horizontal

B. Nearly horizontal

C. Steep

D. First rise and then fall

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4

According to fan laws, for fans having constant wheel diameter, the pressure varies

A. Directly as fan speed

B. Square of fan speed

C. Cube of fan speed

D. Square root of fan speed

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4

The depth of the bucket for a Pelton wheel is generally ________ the diameter of jet.

A. Equal to

B. 1.2 times

C. 1.8 times

D. Double

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4

Geometric similarity is said to exist between the model and the prototype, if both of them

A. Have identical velocities

B. Are equal in size and shape

C. Are identical in shape, but differ only in size

D. Have identical forces

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4

In an outward flow reaction turbine

A. The water flows parallel to the axis of the wheel

B. The water enters at the centre of the wheel and then flows towards the outer periphery of the wheel

C. The water enters the wheel at the outer periphery and then flows towards the centre of the wheel

D. The flow of water is partly radial and partly axial

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4

By fitting an air vessel to the reciprocating pump, there is always a saving of work done and subsequently saving of power. This saving in case of a single acting reciprocating pump is

A. 39.2 %

B. 48.8 %

C. 84.8 %

D. 88.4 %

What is the correct answer?

4

Which of the following statement is wrong?

A. The reaction turbines are used for low head and high discharge.

B. The angle of taper on draft tube is less than 8°.

C. An impulse turbine is generally fitted slightly above the tail race.

D. A Francis turbine is an impulse turbine.

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4

In axial flow fans and turbines, fluid enters and leaves as follows

A. Radially, axially

B. Axially, radially

C. Axially, axially

D. Radially, radially

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4

The specific speed of a hydraulic turbine depends upon

A. Speed and power developed

B. Discharge and power developed

C. Speed and head of water

D. Speed, power developed and head of water

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4

A Pelton wheel is

A. Tangential flow impulse turbine

B. Inward flow impulse turbine

C. Outward flow impulse turbine

D. Inward flow reaction turbine

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4

According to fan laws, for the fans having constant wheel diameters, the power demand varies

A. Directly as fan speed

B. Square of fan speed

C. Cube of fan speed

D. Square root of fan speed

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4

A hydraulic accumulator normally consists of

A. Two cylinders, two rams and a storage device

B. A cylinder and a ram

C. Two coaxial rams and two cylinders

D. A cylinder, a piston, storage tank and control valve

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4

Which of the following hydraulic unit is used for transmitting increased or decreased torque to the driven shaft?

A. Hydraulic ram

B. Hydraulic intensifier

C. Hydraulic torque converter

D. Hydraulic accumulator

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4

A double overhung Pelton wheel has

A. Two jets

B. Two runners

C. Four jets

D. Four runners

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4

High specific speed of a pump implies it is

A. Centrifugal pump

B. Mixed flow pump

C. Axial flow pump

D. Any one of the above

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4

Francis, Kaplan and propeller turbines fall under the category of

A. Impulse turbines

B. Reaction turbines

C. Axial flow turbines

D. Mixed flow turbines

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4

A Francis turbine is used when the available head of water is

A. 0 to 25 m

B. 25 m to 250 m

C. Above 250 m

D. None of these

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4

For starting an axial flow pump, its delivery valve should be

A. Closed

B. Open

C. Depends on starting condition and flow desired

D. Could be either open or closed

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4

Saving of work done and power by fitting an air vessel to double acting reciprocating pump is of the order of

A. 39.2 %

B. 49.2 %

C. 68.8 %

D. 84.8 %

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4

The cavitation in a hydraulic machine

A. Causes noise and vibration of various parts

B. Reduces the discharge of a turbine

C. Causes sudden drop in power output and efficiency

D. All of the above

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4

The mechanical efficiency of an impulse turbine is

A. Ratio of the actual power produced by the turbine to the energy actually supplied by the turbine

B. Ratio of the actual work available at the turbine to the energy imparted to the wheel

C. Ratio of the Work done on the wheel to the energy of the jet

D. None of the above

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4

The efficiency of jet propulsion for a ship with inlet orifices at right angles to the direction of motion of ship is given by

A. [2(Vr - v) v]/ Vr²

B. 2(Vr + v) v]/ Vr²

C. [(Vr - v) v]/ Vr

D. [(Vr + v) v]/ Vr

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4

Which of the following pump is successfully used for lifting water to the boilers?

A. Centrifugal pump

B. Reciprocating pump

C. Jet pump

D. Airlift pump