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Mechanical Engineering :: Hydraulic Machines

  1. The specific speed of a turbine is the speed of an imaginary turbine, identical with the given turbine, which

  2. A.
    delivers unit discharge under unit head
    B.
    delivers unit discharge under unit speed
    C.
    develops unit power under unit head
    D.
    develops unit power under unit speed

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  3. The runaway speed of a hydraulic turbine is the speed

  4. 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

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  5. The cavitation in a hydraulic machine

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

  8. 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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  9. If the net positive suction head (NPSH) requirement for the pump is not satisfied, then

  10. A.
    no flow will take place
    B.
    cavitation will be formed
    C.
    efficiency will be low
    D.
    excessive power will be consumed

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  11. A turbine develops 10000 kW under a head of 25 metres at 135 r.p.m. Its specific speed is

  12. A.
    175.4 r.p.m.
    B.
    215.5 r.p.m.
    C.
    241.5 r.p.m.
    D.
    275.4 r.p.m

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  13. The power of a centrifugal pump working under constant head and discharge increases with the speed.

  14. A.
    True
    B.
    False

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

  16. A.
    Centrifugal pump
    B.
    Reciprocating pump
    C.
    Jet pump
    D.
    Air lift pump

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  17. Which of the following is not a reaction turbine?

  18. A.
    Furneyron turbine
    B.
    Jonval turbine
    C.
    Thomson's turbine
    D.
    Pelton wheel

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  19. A jet of water is striking at the centre of a curved vane moving with a uniform velocity in the direction of jet. For the maximum efficiency, the vane velocity is __________ of the jet velocity

  20. A.
    one-half
    B.
    one-third
    C.
    two-third
    D.
    three-fourth

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