Numerical Prediction of Sediment Erosion in Semi-Kaplan TurbineBladeswith Changing the Inflow Rate of Sediment

摘要

Semi-Kaplan turbines are good applications for low head, small scale hydro power plants.The turbines are subject to erosive wear when the turbines are operating in sediment-laden water.This wear can reduce the efficiency, changes in flow patterns and even breakdown of turbine and other components.To prevent sediment erosion related problems, predicting the most likely region of erosion would be very helpful for developing erosion-resistant alloys or coating techniques and optimization of hydraulic design of the turbine components.In this study to predict the possible sediment erosion region in runner blades of semi-Kaplan turbine, Grant and Tabakoff model of erosion was adopted and steady state CFD analyses were carried out with changing the inflow rate of sediment.The predicted erosion regions were mainly found on the pressure side for runner blades and the severe erosions occurred near the leading edge of the runner blades because of the local acceleration.Also, it was found that the erosion rate of both runner blades and guide vanes would increase almost linearly with increasing the sediment inflow rate.