Free-Jet Water Turbine

a hydroturbine in which the pressure in the water jet at the inlet to the rotor and at the outlet is equal to the atmospheric pressure; thus, a free-jet turbine is an impulse turbine. The stream of water in such a turbine is directed at the rotor in the form of a free jet. If one annular jet exits from the delivery device and immediately strikes all the blades, the generator is called a nonpartial free-jet water turbine. In partial water turbines the water jet strikes the blades only as the blades pass the jet’s zone of action. With the exception of the Sphindex water turbine proposed in 1963 by the Swiss firm Escher-Wyss, all free jets are partial water turbines. The most common type is the Pelton wheel.