Selection type of turbine

Selection type of turbine

To determine the type of water turbine that will be used in the design of a power micro hydro, need specific speed is calculated. Specific Speed (ns) is defined as the speed in rounds per minute of a turbine in the delusion that all the geometrical indeed similar to the turbine is able to lift 75 kg of water per second up to a height of 1 meter.

ns = 3.65 . n . Q ^0.5 . H ^{(- 0.75)}

ns = 270 – 1000 Kaplan/Propeller
ns = 60 – 350 Francis
ns = 42 – 170 Cross flow
ns = 8 – 72 Pelton
Where :
n = Round turbine speed /Nominal speed (rpm)
Q = Design flow (m3/det)
H = Net Head (m)