49 Questions
What is the main purpose of turbines as described in the text?
Converting hydraulic energy into mechanical energy
Which term is used to define the head available at the inlet of a turbine?
Effective Head
What is the Gross Head of a turbine essentially defined as?
The head race level minus the tail race level
Which factor contributes significantly to the Net Head of a turbine?
Friction loss between water and penstocks
In terms of efficiencies of a turbine, what do 'head loss due to friction' and 'net head' refer to?
Hydraulic properties of turbines
Which type of power generation is currently regarded as the cheapest compared to oil and coal sources?
Hydroelectric power
What is Hydraulic Efficiency defined as?
Ratio of power delivered to runner to power supplied at the inlet of the turbine
How is Mechanical Efficiency calculated?
Power at the shaft of the turbine / Power delivered by water to the runner
What does Volumetric Efficiency measure?
Volume of water actually striking the runner vs. volume of water supplied
How is Overall Efficiency defined?
Ratio of power available at the shaft of the turbine to power supplied by water at the inlet
How are hydraulic turbines classified according to energy at inlet?
Impulse turbines and reaction turbines
In which type of turbine does pressure energy change into kinetic energy as water flows through it?
Impulse turbine
What is a characteristic feature of a tangential flow turbine?
Water flows along the tangent of the runner
Which classification is based on the direction of flow through a turbine's runner?
Tangential flow turbine, radial flow turbine, axial flow turbine, mixed flow turbine
Which parameter defines Volumetric Efficiency?
Volume actually striking vs. volume supplied to a turbine
In which type of hydraulic turbine does kinetic energy change into pressure energy?
Radial flow turbine
What happens to the speed of the turbine when the load on the generator decreases?
The speed of the turbine increases beyond normal
How does the centrifugal governor respond when the speed of the generator increases?
It rotates at an increased speed
What is the role of the sleeve in the control system described?
Moves vertically to adjust water flow
Why does the lever turn about the fulcrum in the control system?
Due to the movement of the sleeve
Which action leads to an increase in the rate of flow of water to the turbine?
Moving the piston rod of the control valve upwards
What is the primary function of the servomotor in this control system?
Exert force on the piston to control water flow
What happens to the kinetic energy rejected at the outlet of a turbine when a draft-tube is not used?
It is wasted to the tail race.
Why does the net head on the turbine increase when a draft-tube is used?
To prevent kinetic energy loss and convert it into useful pressure energy.
What is the purpose of governing in a turbine system?
To regulate the flow rate through the turbines according to load conditions.
What component is used for governing in a Pelton turbine system?
Centrifugal governor
What is essential for keeping the speed of a turbine constant under varying load conditions?
Maintaining a constant speed of the generator.
Why is it necessary to govern a turbine?
To keep the generator running at a constant speed.
What is one reason why governing is essential for a turbine coupled to an electric generator?
To maintain constant speed under fluctuating load conditions.
What is the main function of the casing in a Pelton turbine?
Prevent water splashing and discharge water to tail race
What is the role of the breaking jet in a Pelton turbine?
Stop the runner due to inertia
In a Pelton turbine, what material are the buckets typically made of?
Cast steel
What happens when the spear in the nozzle is pushed forward in a Pelton turbine?
The amount of water striking the runner is increased
What defines an outward radial flow turbine?
Water flows from outwards to inwards radially
Which type of turbine is named after L.A. Pelton?
Pelton wheel turbine
What is the main energy form available at the inlet of a Pelton turbine?
$KE$ (Kinetic Energy)
What is the purpose of splitting the jet by a dividing wall in a Pelton wheel bucket?
Divide the jet into two equal parts
What happens when the spear is pushed back in a Pelton nozzle?
Amount of water striking increases
What defines an inward radial flow turbine?
Water flows inwards to outwards radially
In the design of a Pelton wheel, which of the following is NOT a parameter to be determined?
Height of the draft-tube
What is the flow ratio formula for a Francis turbine?
Flow ratio = Vf1/SQ ROOT(2gH)
Which type of turbine has vanes that are adjustable?
Kaplan Turbine
What is the purpose of a draft tube in a turbine system?
To allow water discharge to the tail race
What does the speed ratio represent in a Francis Turbine system?
Ratio of turbine runner speed to Sq.root(2gH)
What is the significance of having a draft tube in a Kaplan Turbine?
Establishes negative head at outlet of runner
For which type of turbine does water flow parallel to the axis of rotation of the shaft?
'Axial flow turbine'
'Hub' or 'boss' in a turbine system refers to what component?
'Part where vanes are fixed'
Which type of turbine was designed by an Austrian Engineer and is suitable for locations with low head water availability?
Kaplan Turbine
What does 'n' represent in the design of Francis Turbines?
Width-to-diameter ratio of wheel
Learn about turbines, which are hydraulic machines that convert hydraulic energy into mechanical energy to generate electricity. Understand how hydroelectric power is generated and why it is considered to be one of the cheapest forms of power generation.
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