Hydroelectric Power Generation
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Questions and Answers

What is the main purpose of turbines as described in the text?

  • Generating hydraulic energy from mechanical energy
  • Transforming electrical energy into mechanical energy
  • Converting hydraulic energy into mechanical energy (correct)
  • Converting mechanical energy into hydraulic energy
  • Which term is used to define the head available at the inlet of a turbine?

  • Loss Head
  • Effective Head (correct)
  • Gross Head
  • Friction Head
  • What is the Gross Head of a turbine essentially defined as?

  • The head loss due to friction in the penstocks
  • The head race level minus the tail race level (correct)
  • The total head loss in a turbine system
  • The head available at the inlet of the turbine
  • Which factor contributes significantly to the Net Head of a turbine?

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

    In terms of efficiencies of a turbine, what do 'head loss due to friction' and 'net head' refer to?

    <p>Hydraulic properties of turbines</p> Signup and view all the answers

    Which type of power generation is currently regarded as the cheapest compared to oil and coal sources?

    <p>Hydroelectric power</p> Signup and view all the answers

    What is Hydraulic Efficiency defined as?

    <p>Ratio of power delivered to runner to power supplied at the inlet of the turbine</p> Signup and view all the answers

    How is Mechanical Efficiency calculated?

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

    What does Volumetric Efficiency measure?

    <p>Volume of water actually striking the runner vs. volume of water supplied</p> Signup and view all the answers

    How is Overall Efficiency defined?

    <p>Ratio of power available at the shaft of the turbine to power supplied by water at the inlet</p> Signup and view all the answers

    How are hydraulic turbines classified according to energy at inlet?

    <p>Impulse turbines and reaction turbines</p> Signup and view all the answers

    In which type of turbine does pressure energy change into kinetic energy as water flows through it?

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

    What is a characteristic feature of a tangential flow turbine?

    <p>Water flows along the tangent of the runner</p> Signup and view all the answers

    Which classification is based on the direction of flow through a turbine's runner?

    <p>Tangential flow turbine, radial flow turbine, axial flow turbine, mixed flow turbine</p> Signup and view all the answers

    Which parameter defines Volumetric Efficiency?

    <p>Volume actually striking vs. volume supplied to a turbine</p> Signup and view all the answers

    In which type of hydraulic turbine does kinetic energy change into pressure energy?

    <p>Radial flow turbine</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 beyond normal</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 sleeve in the control system described?

    <p>Moves vertically to adjust water flow</p> Signup and view all the answers

    Why does the lever turn about the fulcrum in the control system?

    <p>Due to the movement of the sleeve</p> Signup and view all the answers

    Which action leads to an increase in the rate of flow of water to the turbine?

    <p>Moving the piston rod of the control valve upwards</p> Signup and view all the answers

    What is the primary function of the servomotor in this control system?

    <p>Exert force on the piston to control water flow</p> Signup and view all the answers

    What happens to the kinetic energy rejected at the outlet of a turbine when a draft-tube is not used?

    <p>It is wasted to the tail race.</p> Signup and view all the answers

    Why does the net head on the turbine increase when a draft-tube is used?

    <p>To prevent kinetic energy loss and convert it into useful pressure energy.</p> Signup and view all the answers

    What is the purpose of governing in a turbine system?

    <p>To regulate the flow rate through the turbines according to load conditions.</p> Signup and view all the answers

    What component is used for governing in a Pelton turbine system?

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

    What is essential for keeping the speed of a turbine constant under varying load conditions?

    <p>Maintaining a constant speed of the generator.</p> Signup and view all the answers

    Why is it necessary to govern a turbine?

    <p>To keep the generator running at a constant speed.</p> Signup and view all the answers

    What is one reason why governing is essential for a turbine coupled to an electric generator?

    <p>To maintain constant speed under fluctuating load conditions.</p> Signup and view all the answers

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

    <p>Prevent water splashing and discharge water to tail race</p> Signup and view all the answers

    What is the role of the breaking jet in a Pelton turbine?

    <p>Stop the runner due to inertia</p> Signup and view all the answers

    In a Pelton turbine, what material are the buckets typically made of?

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

    What happens when the spear in the nozzle is pushed forward in a Pelton turbine?

    <p>The amount of water striking the runner is increased</p> Signup and view all the answers

    What defines an outward radial flow turbine?

    <p>Water flows from outwards to inwards radially</p> Signup and view all the answers

    Which type of turbine is named after L.A. Pelton?

    <p>Pelton wheel turbine</p> Signup and view all the answers

    What is the main energy form available at the inlet of a Pelton turbine?

    <p>$KE$ (Kinetic Energy)</p> Signup and view all the answers

    What is the purpose of splitting the jet by a dividing wall in a Pelton wheel bucket?

    <p>Divide the jet into two equal parts</p> Signup and view all the answers

    What happens when the spear is pushed back in a Pelton nozzle?

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

    What defines an inward radial flow turbine?

    <p>Water flows inwards to outwards radially</p> Signup and view all the answers

    In the design of a Pelton wheel, which of the following is NOT a parameter to be determined?

    <p>Height of the draft-tube</p> Signup and view all the answers

    What is the flow ratio formula for a Francis turbine?

    <p>Flow ratio = Vf1/SQ ROOT(2gH)</p> Signup and view all the answers

    Which type of turbine has vanes that are adjustable?

    <p>Kaplan Turbine</p> Signup and view all the answers

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

    <p>To allow water discharge to the tail race</p> Signup and view all the answers

    What does the speed ratio represent in a Francis Turbine system?

    <p>Ratio of turbine runner speed to Sq.root(2gH)</p> Signup and view all the answers

    What is the significance of having a draft tube in a Kaplan Turbine?

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

    For which type of turbine does water flow parallel to the axis of rotation of the shaft?

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

    'Hub' or 'boss' in a turbine system refers to what component?

    <p>'Part where vanes are fixed'</p> Signup and view all the answers

    Which type of turbine was designed by an Austrian Engineer and is suitable for locations with low head water availability?

    <p>Kaplan Turbine</p> Signup and view all the answers

    What does 'n' represent in the design of Francis Turbines?

    <p>Width-to-diameter ratio of wheel</p> Signup and view all the answers

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