Abstract:
To study the abrasion rule of Francis turbine with high sediment concentration, the SST k-ω turbulence model and Tabakoff abrasion model were employed to simulate the multiphase flow and sediment erosion phenomenon in the Francis turbine of Weijiabu Hydropower Station in the Weihe River area. The abrasive areas on different components were predicted and the causes of abrasion were analyzed. Compared with the turbine abrasion after operation of the power station, the numerical simulation results accurately predict the location and degree of abrasion. The numerical simulation results show that the erosion mainly occurs in the irregular boundary areas such as the tongue of the volute, the unsmooth area or gap of the surface-to-surface connection, and the leading edge of the guide vane and blade. The flow pattern near the wall has an important influence on erosion. The most serious erosion damage is the blade area near the down wear ring at the outlet of the impeller, where the curvature of the blade bending is large, forming a high speed and unstable flow phenomenon. The elbow of draft tube changes the flow direction of fluid, which leads to serious abrasion. The research results provide a reference for the prevention of turbine abrasion and the optimal design of anti-abrasion turbine.