Working of Pelton turbine

   The Pelton wheel turbine is a tangential flow impulse turbine. The water strikes the bucket along the tangent of the runner. All the available energy of water is converted into kinetic energy or velocity head by passing it through a contracting nozzle provided at end of the p enstock. This turbine is used for high head and is named after the American engineer Lester Pelton.

Diagram:-

CONSTRUCTION DETAILS OF PELTON TURBINE: 

Components of the Pelton turbine:-

     .   Penstock:- It is large sized pipeline through which the water is    provided to the turbine runner from the dam.

• Nozzle: – the amount of water striking the vanes (buckets) of the runner is controlled by providing a spear (flow regulating arrangement) in the nozzle.
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• Spear: – the spear is a conical needle which is operated either by a hand wheel or automatically in an axial direction depending upon the size of the unit. When the spear is pushed forward into the nozzle the amount of water striking the runner is reduced. On the other hand, if the spear pushed back, the amount of water striking the runner increased.

·Runner with bucket: – Runner of Pelton wheel consists of a circular disc on the periphery of which a number of buckets evenly spaced are fixed.The shape of the buckets is of a double hemispherical cup or bowl. Each bucket is divided into two symmetrical parts by a dividing wall which is known as splitter.

• Casing: – The function of casing is to prevent the splashing of the water and to discharge water to tail race.It also acts as safeguard against accidents. It is made up of cast iron or fabricated steel plate.The casing of steel plate does not perform any hydraulic function.

• Breaking jet: – When the nozzle is completely closed by moving the spear in the forward direction the amount of water striking the runner reduce to zero, but the runner due to inertia goes to revolving for a long time . To stop stop the runner in a short time, a small nozzle is provided which directs the jet of water on the back of vanes. This jet of water is called breaking of jet.

WORKING OF PELTON TURBINE

The amount of water striking the vanes (buckets) of the runner is controlled by providing a spear (flow regulating arrangement) in the nozzle.Then the efficient nozzle that converts the hydraulic energy into a high speed jet. The turbine rotor is called runner. The turbine rotor rotates the generators rotor and then produces electricity.

Introduction to fluid mechanics & fluid

• Fluid Mechanics is a branch of science which involve study of behavior of fluid at rest or in motion. This branch of engineering deals with the static, dynamic and kinematic aspects of fluid.
• Fluid statics: It is the study of  fluid when it is at rest.
• e.g.- still water in a tank or a dam. 
• Fluid dynamics: It is the study of behavior of fluid when fluid is in motion, considering all the pressure forces involved during the motion of fluid.
• Fluid kinematics: It is the study of behavior of fluid, when fluid is in motion, ignoring or without considering the pressure forces involved during the flow of fluid.

• What is fluid?
• As the name suggests, in general we can term a material as fluid if it is capable of flowing.
• fluid is a substance having fluidity (ability to flow)  (or)
•  Any substance or material which deforms continuously when subjected to an external shearing force is termed as fluid.
• Examples: All gases and liquids are the examples of fluid (including water vapors/steam)