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Mechanical Engineering :: Hydraulic Machines

  1. 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

  2. A.
    39.2%
    B.
    48.8%
    C.
    84.8%
    D.
    88.4%

  3. In a reciprocating pump, air vessels are used to

  4. A.
    smoothen the flow
    B.
    reduce suction head
    C.
    increase delivery head
    D.
    reduce acceleration head

  5. In a Francis turbine, the pressure at inlet is __________ that at outlet.

  6. A.
    less than
    B.
    more than

  7. If the ratio's of the corresponding forces acting at corresponding points are equal, then the model and the prototype are said to have.

  8. A.
    geometric similarity
    B.
    kinematic similarity
    C.
    dynamic similarity
    D.
    none of these

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

  10. A.
    0.26
    B.
    0.36
    C.
    0, 46
    D.
    0.56

  11. 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

  12. A.
    39.2%
    B.
    48, 8%
    C.
    84.8%
    D.
    88.4%

  13. If the Francis turbine is run below 50 percent head for a long period, it will not only lose its efficiency but also the cavitation danger will become more serious.

  14. A.
    Agree
    B.
    Disagree

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


  16. In a Francis turbine runner, the number of blades are generally between

  17. A.
    2 to 4
    B.
    4 to 8
    C.
    8 to l6
    D.
    16 to 24

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

  19. A.
    ηh = ηo x ηm
    B.
    ηm = ηo x ηh
    C.
    ηo = ηh x ηm
    D.
    none of these