Calculation of sand–water flow and experimental study of sediment erosion in injector of Pelton turbine

With the rapid development of high-head hydraulic resources in the southwest of China, the problem of sediment erosion of large Pelton turbines has attracted increasing attention. Based on the design data of a 500 MW single-unit Pelton turbine of a hydropower station, a model of a 400 mm circular diameter Pelton turbine has been developed. The SST k-ω turbulence model, the volume of fluid method, and a Lagrangian equation for particle motion are used to analyze the distribution of sediment concentration and velocity on the surface of the injector. A mathematical model of sediment erosion of a Pelton turbine injector is established on the basis of the sediment erosion test and the results of internal flow simulation. It is found that the maximum erosion rate of the needle test block is 0.80 μm/h, and the erosion rate of the nozzle is 2.50 μm/h. The results of this study provide a theoretical basis and technical guidance for the prediction of sediment erosion in real large Pelton turbines.