Numerical Simulation And Pressure Pulsation Analysis In A Francis Turbine With Splitter Blades

Based on the computational fluid dynamics(CFD), this paper has discussed the only long-blades runner(general runner), with a short-blades runner (runner with splitter blades) of the Francis turbine worked at the two small flow(40%,60%) operating conditions for a steady, unsteady numerical simulation. Compared the flow field distribution of the full passages of two hydraulic turbine runners, obtained the effect of splitter blades to flow field of the Francis turbine. Besides used signal analysis techniques to analyse the pressure fluctuation of the full passage of the Francis turbine with splitter blades.In this paper, based on the parameters of HLA-351-LJ-170 prototype Francis turbine of a hydropower station. With professional geometric software, established the full passage of the turbine. And the full passage is divided into 2.2 millions grids. The volute, guide apparatus, runner using adaptive tetrahedral mesh; the tube draft using hexahedral mesh.In the calculation process, this article are based on the Reynolds-Averaged N-S equations, closed with the RNGk-εmodel, used SIMPLE algorithm based collocated grid to decouple the Pressure-Linked Equations. The steady simulation results is used to as initial conditions of the unsteady simulation, unsteady calculation time step 0.001s, total 5s. In the analysis of pressure pulsation process, only used the data from 2s to 5s.It is important reference to the development and design of high-head Francis turbine.