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4

The runaway speed of a hydraulic turbine is the speed

A. At full load

B. At which there will be no damage to the runner

C. Corresponding to maximum overload permissible

D. At which the turbine will run freely without load

Correct Answer :

D. At which the turbine will run freely without load


Related Questions

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4

The number of buckets on the periphery of a Pelton wheel is given by

A. (D/2d) + 5

B. (D/2d) + 10

C. (D/2d) + 15

D. (D/2d) + 20

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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

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

Maximum impulse will be developed in hydraulic ram when

A. Waste valve closes suddenly

B. Supply pipe is long

C. Supply pipe is short

D. Ram chamber is large

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4

The speed of an imaginary turbine, identical with the given turbine, which will develop a unit power under a unit head, is known as

A. Normal speed

B. Unit speed

C. Specific speed

D. None of these

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4

The maximum hydraulic efficiency of an impulse turbine is (where φ = Angle of blade tip at outlet)

A. (1 + cos φ)/2

B. (1 - cos φ)/2

C. (1 + sin φ)/2

D. (1 - sin φ)/2

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4

A turbine is required to develop 1500 kW at 300 r.p.m. under a head of 150 m. Which of the following turbine should be used?

A. Pelton wheel with one nozzle

B. Pelton wheel with two or more nozzles

C. Kaplan turbine

D. Francis turbine

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4

The specific speed of a turbine is given by the equation

A. N√P / H3/2

B. N√P / H²

C. N√P / H5/4

D. N√P / H3

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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

In a centrifugal pump casing, the flow of water leaving the impeller, is

A. Rectilinear flow

B. Radial flow

C. Free vortex motion

D. Forced vortex

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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

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

The ratio of the normal force of jet of water on a plate inclined at an angle of 30° as compared to that when the plate is normal to jet, is

A. 1/√2

B. 1/2

C. 1

D. √2

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4

The Fourneyron turbine is _________ reaction turbine.

A. An axial flow

B. An inward flow

C. An outward flow

D. A mixed flow

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4

Head developed by a centrifugal pump is

A. Proportional to diameter of impeller

B. Proportional to speed of impeller

C. Proportional to diameter and speed of impeller

D. None of the above

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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

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4

The force exerted by a jet of water (in a direction normal to flow) impinging on a fixed plate inclined at an angle θ with the jet is

A. waV/2g × sinθ

B. waV/g × sinθ

C. waV²/2g × sin2θ

D. waV²/g × sinθ

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4

The function of guide vanes in a reaction turbine is to

A. Allow the water to enter the runner without shock

B. Allow the water to flow over them, without forming eddies

C. Allow the required quantity of water to enter the turbine

D. All of the above

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4

The specific speed of turbine is defined as the speed of a unit

A. Of such a size that it delivers unit discharge at unit head

B. Of such a size that it delivers unit discharge at unit power

C. Of such a size that it requires unit power per unit head

D. Of such a size that it produces unit horse power with unit head

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4

In a Francis turbine runner, the numbers of blades are generally between

A. 2 to 4

B. 4 to 8

C. 8 to 16

D. 16 to 24

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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

Delivery head of a centrifugal pump is

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

Slip of a reciprocating pump is negative, when

A. Suction pipe is short and pump is running at low speeds

B. Delivery pipe is long and pump is running at high speeds

C. Suction pipe is short and delivery pipe is long and the pump is running at low speeds

D. Suction pipe is long and delivery pipe is short and the pump is running at high speeds

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4

According to fan laws, at constant speed and capacity, the pressure and power vary

A. Directly as the air or gas density

B. Inversely as square root of density

C. Inversely as density

D. As square of density

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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

The maximum number of jets, generally, employed in an impulse turbine without jet interference are

A. Two

B. Four

C. Six

D. Eight

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4

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

A. Horizontal

B. Nearly horizontal

C. Steep

D. First rise and then fall

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4

The relation between hydraulic efficiency (ηh), mechanical efficiency (ηm) and overall efficiency (ηo) is

A. ηh = ηo × ηm

B. ηm = ηm × ηh

C. ηo = ηh × ηm

D. None of these

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4

Mechanical efficiency of a centrifugal pump is the ratio of

A. Energy available at the impeller to the energy supplied to the pump by the prime mover

B. Actual workdone by the pump to the energy supplied to the pump by the prime mover

C. Energy supplied to the pump to the energy available at the impeller

D. Manometric head to the energy supplied by the impeller per kN of water