Numerical studies on sediment erosion due to sediment characteristics in Francis hydro turbine

Abstract

Sediment erosion is the wear phenomenon from the hard abrasive particle found in the rivers. Sediment erosion is an inevitable process in the hydropower. It deteriorates the turbine shape and structure and increasing the maintenance expenses. There are various methods to improve the runner to operate against the sediment erosion. Firstly, the turbine material can be modified to the harder material but it will be costly and difficult for the manufacturing. Secondly, regular maintenance of the turbine needs to be done but it is the tedious task and hinder the power generation from the hydropower. Thirdly, the critical area of the runner blade surface which is vulnerable to sediment erosion need to identify and modification of the turbine shape according to it by altering the design parameter of the blade. The modification such as a change in thickness, blade angle and coating is possible for minimizing the effect of sediment erosion. The determination of the vulnerable area in the runner for the sediment erosion is a difficult task considering the many parameters included in sediment erosion phenomenon. The parameter such as sediment size, sediment shape, sediment concentration, sediment velocity, sediment hardness, impact angle and operating condition of hydropower. The precise prediction of the sediment erosion in the turbine is the difficult task due to the synergetic effect of parameters. The accurate and precise indication of the sediment erosion required both experimental and computational analysis. After identification of the susceptible area of sediment erosion, modification and optimization will be performed to reduce the effect of the sediment erosion without falling in the performance of the turbine.