Centrifugal Pumps and Hydraulic Energy Conversion Quiz
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Questions and Answers

What is the primary function of a centrifugal pump?

  • Convert electrical energy into pressure energy
  • Convert pressure energy into rotational energy
  • Convert mechanical energy into pressure energy (correct)
  • Convert hydraulic energy into mechanical energy
  • How does the flow occur in centrifugal pumps?

  • Radial outward direction (correct)
  • Circular motion
  • Random chaotic flow
  • Axial inward direction
  • What type of flow principle does a centrifugal pump work on?

  • Forced vortex flow (correct)
  • Natural convection flow
  • Laminar flow
  • Turbulent flow
  • What part of a centrifugal pump is responsible for rotating the liquid?

    <p>Impeller</p> Signup and view all the answers

    How does the rise in pressure head in a centrifugal pump vary with the tangential velocity of the liquid?

    <p>It is proportional to the square of velocity</p> Signup and view all the answers

    Which part of a centrifugal pump is connected to the shaft of an electric motor?

    <p>'Impeller'</p> Signup and view all the answers

    What is the precaution against cavitation related to the pressure of the flowing liquid in the hydraulic system?

    <p>Maintaining the pressure above the vapour pressure of the liquid</p> Signup and view all the answers

    What effects are observed due to cavitation on turbine blades?

    <p>Roughening of the surface due to pitting action</p> Signup and view all the answers

    How is Net Positive Suction Head (NPSH) defined?

    <p>The pressure at the inlet of the pump minus the vapour pressure head plus velocity head</p> Signup and view all the answers

    How is NPSH related to cavitation-free pump operation?

    <p>Available NPSH should be greater than the required NPSH</p> Signup and view all the answers

    What distinguishes between the required and available NPSH for a pump installation?

    <p>Required NPSH is determined experimentally while available NPSH is given by the pump manufacturer</p> Signup and view all the answers

    What materials are recommended as a precaution against cavitation?

    <p>Aluminium and steel</p> Signup and view all the answers

    What is the main function of the casing surrounding the impeller in a centrifugal pump?

    <p>To convert kinetic energy into pressure energy</p> Signup and view all the answers

    What is the purpose of a foot valve in the suction pipe of a centrifugal pump?

    <p>To prevent backflow of water from the pump</p> Signup and view all the answers

    In a multistage centrifugal pump, impellers connected in series are used primarily to:

    <p>Produce high head</p> Signup and view all the answers

    What is the main function of connecting impellers in parallel in a multistage centrifugal pump?

    <p>To increase pressure</p> Signup and view all the answers

    Which phenomenon describes the formation of vapor bubbles in a flowing liquid due to pressure drop?

    <p>Cavitation</p> Signup and view all the answers

    In a centrifugal pump, what occurs when the pressure of the flowing liquid falls below its vapor pressure?

    <p>Boiling</p> Signup and view all the answers

    What action causes pitting on metallic surfaces due to cavitation in pumps?

    <p>Collapsing of vapor bubbles</p> Signup and view all the answers

    What is the primary reason for connecting multiple impellers on the same shaft in a multistage pump?

    <p>To increase head.</p> Signup and view all the answers

    What is the role of a strainer at the lower end of a suction pipe connected to a centrifugal pump?

    <p>Filter out debris.</p> Signup and view all the answers

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