Numerical Simulation of 3-D Flow in Low Specific Speed Francis Runner with Splitter Blades

The Spalart-Allmaras turbulence model and the standard turbulence model were used to simulate the 3-D flow in low specific speed Francis runner with splitter blades and the simulating capability of these two models were compared. The calculation process was based on continuity equation and Navies-Stokes equation. The governing equations were discretized by finite-volume method and SIMPLIC method was applied to solve the equations. The results show the pressure distribution on the surface of blades under these two models are very similar in different calculations and the deviation are very small near design calculation and increased with the distant from the design calculation and in off-design calculations the deviation are small in most regions of the blades. At the same time, the calculation process using S-A turbulence model are easily convergence and spend low time. It indicates that these two turbulence model has same simulation capability and accuracy and S-A turbulence model has certain advantages.