Study On Sediment Erosion Of Long And Blades Of Turbine Runner With Many Sediments River

When the turbine is operating in a silt-laden river,the turbine’s flow components will suffer serious damage,such as reduced efficiency,damage to the flow components,increased maintenance costs,and even safety problems.After the 2008 Wenchuan Earthquake,debris flows frequently occurred in the upper reaches of the Yuzixi Power Station,resulting in a large amount of sediment in the river.The main mineral components of the sediment were quartz,feldspar and hornblende,which undoubtedly increased the overflow of the power station’s turbine the components cause very serious wear and damage.In this paper,the combination of numerical simulation and experiment is conducted to study the sediment erosion of the turbine runner of Yuzixi Power Station under different operation conditions and different concentrations,and to achieve the prediction for the degree of erosion(erosion rate)of the turbine runner under different sediment concentration under typical operating conditions,guiding power plant early warning and proactively avoiding sensitive operating conditions that can easily lead to serious erosion of the turbine,so as to improve the turbine’s operating characteristics,ensure the unit’s stability and long-term resistance to sediment erosion.The research work and results of this article are as follows:1.Use a three-dimensional scanner to scan the actual turbine runner of Yuzixi Power Station to obtain the coordinate data of the surface shape point of the complex curved surface of the blade.The geometric model of the runner model is then structured meshed.The CAD drawings of the spiral casing,stay vanes and guide vanes and draft tube are imported into the UG software to establish the water body model of the flow component,and then the unstructured mesh is performed.2.According to the sediment characteristics in the running river of Yuzixi Power Station,the numerical simulation method of solid-liquid two-phase flow is adopted,and the design flow conditions are used as the boundary conditions.The CFX is used to numerically calculate the sediment and water flow inside the turbine to simulate.The pressure distribution,velocity distribution and concentration distribution of the flow of sand inside the turbine,especially the velocity characteristics of the impact of the sediment inside the turbine on the surface of the flow component are analyzed.The numerical results show that the long blades have the largest sediment concentration near the shroud near on the pressure surface,and the sediment concentration on the pressure surface is greater than that on the suction surface.The turbine blades have the highest velocity near the shroud surface.Therefore,it can be estimated that the long blades of the runner near the shroud surface are more likely to erosion than other positions of the runner.3.According to the hydrological and sediment data of the Yuzixi Power Station,the numerical calculation results of the sediment and water flow inside the turbine,and the theoretical analysis of the prediction of the serious parts of the sediment erosion,a test system for the sediment erosion of the turbine was built.Design the runner blade sediment erosion test piece and working section to carry out the sediment erosion experimental to obtain the turbine runner sediment erosion situation and fit the quantitative calculation formula of the turbine runner.It can be used as a general calculation model for sediment erosion under different operating conditions and different sediment concentration of turbine runner blades of Yuzixi Power Station.