Hydraulic Turbine Types:
The hydraulic turbine can be calssified into two categories of reaction turbine and implulse turbine according to the principle of their water flow action and structural features. At present, various types of hydraulic turbine produced by manufacturers are mainly as follows:

1. Reaction Turbine
A reaction turbine develops power from the combined action of pressure and moving water. The runner is placed directly in the water stream flowing over the blades rather than striking each individually. Reaction turbines are generally used for sites with lower head and higher flows than compared with the impulse turbines.                                            
Francis    Francis Turbine

Axial-flow Turbine

kaplan turbine runner

Tubular Turbine

2. Impulse Turbine
The impulse turbine generally uses the velocity of the water to move the runner and discharges to atmospheric pressure. The water stream hits each bucket on the runner. There is no suction on the down side of the turbine, and the water flows out the bottom of the turbine housing after hitting the runner. An impulse turbine is generally suitable for high head, low flow applications. And it include two type , the widely is pelton, it suitable water head from 40m to 2000m. The other type is Turgo turbine, it always used  small unit, it suitable water head from 50m to 400m.
Pelton Turbine  

Turgo Turbine

Hydro Turbine Output Power Calculate

Hgross (Gross head )= Upstream level – Downstream level
Hloss (Head loss of the forbay, trashrock, penstock pips, etc)
Working Head Hr (Net head, Rated Head) =Hgross-Hloss
Working flow Qr: The volume of water flow go through turbine in a certain amount of time, flows are normally given in cubic meters per second (m3/s) or in litres per second (l/s). Normally we use the symbol: Qr to represent the rated working flow.
The theoretical power (Ns) available from a given head of water is in exact proportion to the head Hr and the flow Qr:
Ns = 9.81QrHr (kW)
The output power of Turbine Nt = ηNs (η: Efficiency of turbine: 0.85 – 0.94 )
So, the formula to caculate Nt:                  Nt=ηNs = 9.81ηQrHr

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