High Specific Speed Francis Turbine Solid Liquid Two Phase Numerical Simulation

My country is rich in hydropower resources,but in recent years, deforestation andthe destruction of the vegetation leads to river sediment concentration increases, causingserious abrasion of turbine flow components. Although hydropower station has certainremedial measures, but the performance of the turbine is affected by a certain, turbineefficiency drops seriously, power plant operation cost increase, the economic decline.There are many factors might result in water turbine of wear, but failed to give fullconsideration to the effects of sediment particle design stage is a major cause of therunning power station wear, therefore, for the mechanism of sand wear study hasdefinite theoretical significance and practical significance.In this paper, based on the N-S equation respectively with water and sand water asa medium for full passage calculation of high specific speed mixed flow turbinesimulation, analysis of the flow characteristics inside, wear master the law of sedimentparticles on the flow components. In the water the water flow characteristics of turbineinternal condition is better, while the sediment turbine efficiency seriously decline.Inorder to investigate the influence of sediment particles on the turbine performance, theadoption of a single variable method. In the flow and sediment particle diameter isconstant, with the increase of the volume fraction of the wear of sediment flowcomponents intensifies and not linear change, after the increase of the volume fractionof the sedimentwear. In the flow and sediment concentration under the condition ofconstant change, sediment particle diameter on the flow components wear is not asimple quantitative analysis, simulation results show that the sediment particle diameteris smaller and the relative velocity and the water is small, then the sediment particles tohigh speed impact material surface, in addition, with decreasing the size of sedimentgrain, reduce the effect of inertia particles flow components, on the upper position of theimpact is more serious, aggravated the degree of wear of the region, but also wear moreshowing symmetry, and large diameter particles on the wheel, such as guide vane on thelower position of the Department of the Ministry of wear is more serious. When thesediment is constant, flow from small to big changes corresponding to the river from thedry to wet period of transition, for the same turbine, flow rate increases, the machine velocity increased, wear of water turbine will increase. The results show that: no matterwhat kind of conditions, the turbine is the main wear position of bottom of the volutenose, seat ring, a fixed guide vane and guide vane head, inlet and outlet blade runnerand the lower triangle.The numerical simulation results and operation station a flood season wear contrastflow components, the results accord with the actual wear, the flow simulation ofhydraulic turbine internal ANSYS CFX software can be very good. Provide effectivehelp through the simulation results can be optimized and plant leaf type turbine forbetter anti-wear measures.