Numerical Methods for Fluid Dynamical Simulation of Hydro Power Plants

Hydro power plants of any size - be it large or small hydro - are always quite complicated arrangements as they cannot be designed for a definite duty point of operation but in fact the duty point varies strongly with the flow rate and in many cases also with the pressure head available. The optimization of these plants has always been a challenge to the design engineers from all faculties involved, in the course of this presentation mechanical or civil engineering are concerned. Due to the more or less - and sometimes extremely - variable duty points the dimensioning and the set-up in detail are remarkably different from on plant to another - and so is the stationary and transient operation. Both the specific arrangement as well as the varying duty points often cause a number of problems as any hydro power plant exist exactly once and in so far is always a prototype thus often causing unforeseeable difficulties. On the example of a number of components fluid dynamical optimizations by means of numerical methods are outlined for intakes, valves and different turbine designs. Specific problems as they can frequently occur in hydro power and remedy to solve the problems are described. On the example of a cavitating Francis runner a new way for cavitation simulation will be presented.