Pelton Wheel explanation with velocity triangles and work done calculation

 Pelton Wheel:

The Pelton wheel is a tangential flow impulse turbine. In this water strikes the runner tangentially.

Let's what are its various components:

1. Nozzle :
   The purpose of the nozzle is to control the amount of water striking the bucket. The nozzle contains a spear of conical shape that controls the flow of water in the nozzle. When the water jet velocity need at high speed the spear move backward and when the water jet velocity need to be low the spear move forward towards the nozzle
   
   
   
2. Runner with Buckets :
   Periphery is the main body on which buckets are mount .All these buckets are equally spaced and fixed . If you look closely you will observe the shape of the bucket is double hemispherical cup or bowl shape . The wall  that separate the bucket equally into two symmetrical parts is called a splitter . When the jet of water strike the bucket it is the splitter the divide the jet into two equal parts and jet comes out at outer edge of the bucket .
   Note : bucket are shaped in such a way that jet get deflect through 160 to 170 degree
   
   
   
   
   
3. Casing:
   As it name suggest its purpose is to protect the pelton wheel from accidents and the splashing of  the water 
4. Breaking Jet :
   The purpose of breaking jet is to stop the pelton wheel. It is place in suck a way when water release from it . It rotates the pelton wheel in opposite direction to stop it movement.

Velocity Triangle and work done :

Assumption: Let U = velocity of the bucket  u1 =u2 =U

$V_{1} = water jet velocity at inlet$

from the velocity triangle

V₁ = Velocity of jet at inlet 

u = u₁ = u₂ =

$\frac{ \pi DN}{60}$

As we know the flow is tangential at inlet so the velocity triangle is just  a straight line

V_r1 = V₁ – u₁  = V₁ –u

V_w1 = V₁    (V_w1  is nothing just horizontal component of the V₁ )

α =0°  and  θ = 0°