Reaction force on Pelton turbines Relative reaction force Absolute reaction force

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 Newton’s 2. law: The relative flow rate is given by:

Further we can find values for the relative velocities The relative reaction force becomes:

If we use: Then: The relative reaction force becomes:

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 Newton’s 2. law: For a relative velocity, w2 = -(c-u) The absolute reaction force becomes:

Exercise 1 Find FA and FR for the runner velocity u = 0 For Hn = 500 m and ds = 0,10 m

Exercise 2 Find FA and FR for the runner velocity u = 0,5 · c For Hn = 500 m and ds = 0,10 m

Exercise 3 Find FA and FR for the runner velocity u = c For Hn = 500 m and ds = 0,10 m