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4

In a reciprocating pump, air vessels are used to

A. Smoothen the flow

B. Reduce suction head

C. Increase delivery head

D. Reduce acceleration head

Correct Answer :

D. Reduce acceleration head


Related Questions

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4

The efficiency of a hydraulic press is given by (where W = Weight lifted by ram, P = Force applied on plunger, A = Area of ram, and a = Area of plunger)

A. (W/p) × (A/a)

B. (p/W) × (a/A)

C. (W/p) × (a/A)

D. (p/W) × (A/a)

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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

The maximum number of jets generally employed in impulse turbine without jet interference is

A. 4

B. 6

C. 8

D. 12

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4

In centrifugal pumps, maximum efficiency is obtained when the blades are

A. Straight

B. Bent forward

C. Bent backward

D. Radial

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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

Low specific speed of turbine implies it is

A. Propeller turbine

B. Francis turbine

C. Impulse turbine

D. Any one of the above

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4

Which of the following pump is generally used to pump highly viscous fluid?

A. Centrifugal pump

B. Reciprocating pump

C. Air lift pump

D. Screw pump

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4

Impulse turbine is generally fitted

A. At the level of tail race

B. Little above the tail race

C. Slightly below the tail race

D. About 2.5 m above the tail race to avoid cavitations.

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4

The unit speed of the turbine runner is

A. N/√H

B. N/H

C. N/H3/2

D. N/H²

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4

A turbine pump is basically a centrifugal pump equipped additionally with

A. Adjustable blades

B. Backward curved blades

C. Vaned diffusion casing

D. Inlet guide blades

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4

Power required (in watts) to drive a centrifugal pump is (where Hm = Manometric head in metres, w = Specific weight in N/m3, Q = Discharge of the pump in m3/s, and ηo = Overall efficiency of the pump)

A. (w Hm) / (Q × ηo)

B. (w Hm Q) / ηo

C. (w Q) / (Hm × ηo)

D. (w Q ηo) / Hm

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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

Discharge (Q) of a centrifugal pump is given by (where D = Diameter of impeller at inlet, b = Width of impeller at inlet, and Vf = Velocity of flow at inlet)

A. Q = π.D.Vf

B. Q = π.b.Vf

C. Q = π.D.bf.V

D. Q = D.b.Vf

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4

If the ratios of all the corresponding linear dimensions are equal, then the model and the prototype are said to have

A. Geometric similarity

B. Kinematic similarity

C. Dynamic similarity

D. None of these

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4

Head developed by a centrifugal pump depends on

A. Impeller diameter

B. Speed

C. Fluid density

D. Both (A) and (B) above

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4

High specific speed of turbine implies it is

A. Propeller turbine

B. Francis turbine

C. Impulse turbine

D. None of the above

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4

The optimum value of vane exit angle for a centrifugal pump impeller is

A. 10-15°

B. 20-25°

C. 30-40°

D. 50-60°

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4

The impeller of a centrifugal pump may have

A. Volute casing

B. Volute casing with guide blades

C. Vortex casing

D. Any one of these

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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

Which of the following pump is successfully used for lifting water from deep wells?

A. Centrifugal pump

B. Reciprocating pump

C. Jet pump

D. Air lift pump

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4

Which of the following turbine is preferred for a specific speed of 60 to 300 r.p.m.?

A. Pelton wheel

B. Francis turbine

C. Kaplan turbine

D. None of these

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4

Discharge of a centrifugal pump is (where N = Speed of the pump impeller)

A. Directly proportional to N

B. Inversely proportional to N

C. Directly proportional to N²

D. Inversely proportional to N²

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4

The hydraulic efficiency of an impulse turbine is the

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

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

Which of the following is not an impulse turbine?

A. Girad turbine

B. Turgo turbine

C. Pelton wheel

D. Kaplan turbine

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4

The water in a jet propelled boat is drawn through the openings facing the direction of motion of the boat. The efficiency of propulsion is given by

A. 2V/(vr - v)

B. 2V/(vr + v)

C. V/(vr - v)

D. V/(vr + v)

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4

The cavitation in a hydraulic machine is mainly due to

A. Low velocity

B. High velocity

C. Low pressure

D. High pressure

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4

The type of centrifugal pump preferred for a specific speed of 20 r.p.m. is

A. Slow speed pump with radial flow at outlet

B. Medium speed pump with radial flow at outlet

C. High speed pump with radial flow at outlet

D. High speed pump with axial flow at outlet

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4

A centrifugal pump will start delivering liquid only when the pressure rise in the impeller is equal to the

A. Kinetic head

B. Velocity head

C. Manometric head

D. Static head

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4

Braking jet in an impulse turbine is used

A. To break the jet of water

B. To bring the runner to rest in a short time

C. To change the direction of runner

D. None of these