Hydraulic Turbines and Hydroelectric Power Generation
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Questions and Answers

What is the main function of turbines?

  • Convert thermal energy into mechanical energy
  • Convert electrical energy into mechanical energy
  • Convert mechanical energy into hydraulic energy
  • Convert hydraulic energy into mechanical energy (correct)

    • What is the term used to describe the electric power obtained from the hydraulic energy?

  • Hydroelectric power (correct)
  • Thermal power
  • Electric power
  • Hydraulic power

    • What is the Gross Head of a turbine?

  • The head race level minus tail race level when no water is flowing (correct)
  • The efficiency of a turbine
  • The head loss due to friction between penstocks and water
  • The head available at the inlet of the turbine

    • Which term is used interchangeably with 'effective head' for a turbine?

    <p>Net head</p> Signup and view all the answers

    What are losses caused by bend, pipe fittings, and entrance of penstock collectively known as?

    <p>Frictional losses</p> Signup and view all the answers

    In the equation H = Hg - hf, what does 'hf' represent?

    <p>Friction head loss between penstocks and water</p> Signup and view all the answers

    What is the main difference between an inward radial flow turbine and an outward radial flow turbine?

    <p>Direction of water flow</p> Signup and view all the answers

    Which type of turbine is a Pelton wheel?

    <p>Tangential flow impulse turbine</p> Signup and view all the answers

    What is the function of the casing in a Pelton turbine?

    <p>Prevent splashing of water</p> Signup and view all the answers

    Why is a breaking jet used in a Pelton turbine?

    <p>To stop the runner quickly</p> Signup and view all the answers

    What is controlled by a spear in the nozzle of a Pelton turbine?

    <p>Amount of water striking the runner</p> Signup and view all the answers

    How are the buckets of a Pelton wheel shaped to deflect the water jet?

    <p>$160^{ ext{o}}$</p> Signup and view all the answers

    What part of a Pelton wheel divides the jet into two equal parts before it strikes the buckets?

    <p>$90^{ ext{o}}$ splitter</p> Signup and view all the answers

    What describes a tangential flow impulse turbine like a Pelton wheel?

    <p>$180^{ ext{o}}$ water flow</p> Signup and view all the answers

    Which material is NOT typically used for making the buckets of a Pelton wheel?

    <p>$180^{ ext{o}}$ splitter</p> Signup and view all the answers

    What is the mathematical expression for hydraulic efficiency?

    <p>Power at shaft/Power supplied at inlet</p> Signup and view all the answers

    Which type of turbine is identified by having only kinetic energy at the inlet?

    <p>Impulse turbine</p> Signup and view all the answers

    What does volumetric efficiency measure?

    <p>Volume of water striking the runner</p> Signup and view all the answers

    In a reaction turbine, what happens to the pressure energy as water flows through the runner?

    <p>Changes into kinetic energy</p> Signup and view all the answers

    Which type of turbine is enclosed in an air-tight casing?

    <p>Tangential flow turbine</p> Signup and view all the answers

    What is the definition of mechanical efficiency?

    <p>Power at shaft of the turbine/Power delivered by water to the runner</p> Signup and view all the answers

    'Specific speed' is a classification criterion based on what aspect of hydraulic turbines?

    <p>Energy available at inlet</p> Signup and view all the answers

    What is the primary reason for a decrease in power as water flows over the vanes of a turbine?

    <p>Hydraulic losses</p> Signup and view all the answers

    'Overall Efficiency' is defined as the ratio of what variables?

    <p>'Power available at shaft' to 'Power supplied at inlet'</p> Signup and view all the answers

    'Volumetric Efficiency' measures the ratio of what volumes?

    <p>'Water striking the runner' to 'Water supplied to turbine'</p> Signup and view all the answers

    What is the purpose of the draft-tube in a turbine system?

    <p>To create a negative head at the outlet of the runner</p> Signup and view all the answers

    In the design of a Pelton wheel, what is determined as 5 times the diameter of the jet?

    <p>Width of the buckets</p> Signup and view all the answers

    Who is the modern Francis Turbine named after?

    <p>J.B. Francis</p> Signup and view all the answers

    What type of turbine is a Francis Turbine?

    <p>Mixed flow type turbine</p> Signup and view all the answers

    What is the speed ratio for a Francis Turbine?

    <p>$u1 / \sqrt{2gH}$</p> Signup and view all the answers

    In an inward flow reaction turbine, where does the water enter and leave?

    <p>Enters radially, leaves axially</p> Signup and view all the answers

    'Hub' or 'boss' in an axial flow reaction turbine serves as what?

    <p>Blade attachment point</p> Signup and view all the answers

    'Flow ratio' for a Francis Turbine is expressed as?

    <p>$Vf1/ \sqrt{2gH}$</p> Signup and view all the answers

    What happens to the speed of the turbine when the load on the generator decreases?

    <p>The speed of the turbine increases.</p> Signup and view all the answers

    How does the centrifugal governor respond when the speed of the generator increases?

    <p>It rotates at an increased speed.</p> Signup and view all the answers

    What is the role of the fly-balls in the centrifugal governor system?

    <p>To respond to changes in centrifugal force.</p> Signup and view all the answers

    When the sleeve moves upward, what happens to the piston rod of the control valve?

    <p>It moves downward.</p> Signup and view all the answers

    What effect does closing valve V have on the rate of flow of water to the turbine?

    <p>Decreases it.</p> Signup and view all the answers

    How does increasing the area of flow of water at the outlet of the nozzle affect the speed of the turbine?

    <p>Increases it.</p> Signup and view all the answers

    What is the purpose of a draft-tube in a turbine?

    <p>Convert kinetic energy into useful pressure energy</p> Signup and view all the answers

    What is the main function of governing in a turbine system?

    <p>Regulate the flow rate through the turbines</p> Signup and view all the answers

    Which type of draft-tube is known to be most efficient?

    <p>Conical draft-tubes</p> Signup and view all the answers

    What happens if a reaction turbine is not fitted with a draft-tube?

    <p>Water freely discharges into the tail race</p> Signup and view all the answers

    Why is it important to keep the speed of a turbine constant?

    <p>To ensure constant power generation by the generator</p> Signup and view all the answers

    How does governing help in maintaining constant speed of a turbine?

    <p>By regulating flow through the turbines based on load conditions</p> Signup and view all the answers

    What drives the gear pump in an oil pressure governor for a Pelton turbine?

    <p>The power obtained from the turbine shaft</p> Signup and view all the answers

    Which element is responsible for driving the centrifugal governor in governing a Pelton turbine?

    <p>Centrifugal governor or pendulum</p> Signup and view all the answers

    What part of an oil pressure governor receives power from the turbine shaft?

    <p>The gear pump also called oil pump, which is driven by the power obtained from turbine shaft</p> Signup and view all the answers

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