Reaction force on Pelton turbines

1
Reaction force on Pelton turbines

• Relative reaction force
• Absolute reaction force

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Relative reaction force acting on the Pelton
runner
The relative reaction force is the force acting
from the jet on a bucket when the runner is
rotating. This force can be found by the help of
Newtons 2. law
The relative flow rate is given by
3
Further we can find values for the relative
velocities
The relative reaction force becomes
4
If we use
Then
The relative reaction force becomes
5
Absolute reaction force acting on the Pelton
runner
The absolute reaction force can be found by
calculating the impulse from the jet. This force
can be found by the help of Newtons 2. law
For a relative velocity, w2 -(c-u) The
absolute reaction force becomes
6
Exercise 1
Find FA and FR for the runner velocity u 0 For
Hn 500 m and ds 0,10 m
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Exercise 2
Find FA and FR for the runner velocity u 0,5
c For Hn 500 m and ds 0,10 m
8
Exercise 3
Find FA and FR for the runner velocity u c For
Hn 500 m and ds 0,10 m