Three dimensional viscous flow simulation in a Mixed-Francis turbine

Francis turbines are one of the most popular turbines used in hydraulic power plants. In this paper, several relations are introduced to determine the approximate shape of the turbine runner and then the fluid flows inside the runner as well as the draft tube are numerically simulated. First, an approximate shape for the runner passage (i.e. hub and shroud profiles) is determined which is based on experimental data and then using the provided data for H, and N the runner blades are designed. Flow simulations are based on the 3 D solution of the Navier-Stokes equations for incompressible turbulent flows. A commercially available CDF code is used for the numerical simulation. The numerical results for flows inside the turbine runner and the tube indicate the capacity of the code for such flow simulations and show that such utilities could be used to numerically investigated phenomena such as cavitation and separation inside turbo mechanics. In addition, these CFD codes could be used in shape optimization for turbine blades