| The efficiency is expressed
in percent. It is defined as the obtained mechanical energy in the turbine shaft divided
by the supplied energy from the water flowing through the turbine. The efficiency of the water turbine is very high: compare for instance with the efficiency of the combustion engine (car engine), steam turbine and gas turbine, all lying around 40%. |
The curves are valid for the turbines in Krokströmmen power plant. In this plant there are two Francis turbines and one Kaplan turbine, which operate at the same head (58m). The flow of the two Francis turbines at full load is about half the maximum flow of the Kaplan turbine. The Francis-curve in the diagram represents both Francis units operating in parallel at the same flow. The diagram therefore gives a direct comparison between the efficiensies för the Francis- and the Kaplan turbine in general att the same head and flow. |
| < turbine types < hydro power < the function of a turbine |
kaplan
> (also semikaplan, propeller) francis > |
