Assignment Chapter 10 A Pelton turbine is designed to develop power having a wheel diameter D = 2.5 m, a water head
at the inlet of the nozzle of H = 500 m and a flow rate of Q = 3 m/s, with a rotating speed
N = 290 rpm. The nozzle efficiency nn = 0.95, the relative flow exiting from the bucket is
such that a = 165º and the velocity coefficient of the bucket is Cyb = 0.96. Assume that the
mechanical and volumetric efficiencies are respectively nm = 0.9 and no = 0.96.
1) Calculate the different velocity components (U. V.W. WW. V) and draw the velocity
diagrams at the inlet and outlet of the bucket.
2) Determine: i) the hydraulic efficiency in, ii) the output power Ps, iii) the output torque Ts and
iv) the jet diameter dn.
3) Calculate the maximum hydraulic cfficiency numar and the corresponding power shaft and
torque
I
4) State briefly why a Pelton turbine is an impulse turbine.
Bucket
Top view
Jet
Nozzle
a
U
W2​