Study On Internal Flow And Wear Of Turbine Runner In Sediment-laden River Hydropower Station

There is much sediment in rivers in China,especially in flood season.Serious erosion and wear of sediment are inevitable for turbines working in high sediment-laden water.The damage of turbine flow passage components will be aggravated,resulting in the reduction of stability and efficiency of turbine units,high-frequency overhaul or huge potential risks to the safe operation of the entire power station,thus greatly reducing economic benefits.Because of the high concentration of sand and water,sharp edges and sharp grains of sand,and the high content of quartz,the hydropower stations running on the Kizi River are facing a great test of sediment erosion,especially the Xiate hydropower station,which will be built on the river basin,has a high head.Therefore,it is necessary to analyze the erosion and wear of the sediment of the hydropower station.Runner is the core component of hydraulic turbine.It is of great significance to carry out numerical simulation analysis and wear test under sand and water conditions.The work and results of this study are as follows:1.Unigraphics modeling software was used to model the three-dimensional entity of the flow passage parts of the HLA351-LJ-275 Francis turbine.Using ANSYS ICEM software,the hexahedral structure meshing is carried out for models of different flow passage components,and the boundary is set according to the real machine flow conditions.2.According to the flow information of the sandy water in the turbine under different working conditions,the numerical computation was carried out by CFX solver.The pressure,velocity and sediment volume concentration distribution of the flow components of the turbine under different working conditions were extracted and analyzed.The results show that the sediment concentration on the pressure side of the blade is larger than that on the suction side,and the maximum sediment concentration on each blade surface appears at the tail of the blade.The maximum concentration occurs at the 20% height of the tail of the blade adjacent to the crown.The sediment velocity at the tail of the blade is the highest and the highest velocity is near the outlet of the band.It can be inferred that the area with the most severe blade wear should be at the outlet of the blade and the area adjacent to the band has higher sand-water velocity,which makes it more vulnerable to wear.3.The surface topography method was used to conduct the sediment erosion test on the HLA351-LJ-275 runner blades of the Xiate Hydropower Station.The wear of the key positions of the runner blades was analyzed to prevent the sediment of the turbines of the Xiate Hydropower Station.The eclipse design provides a certain important basis.