Calculation And Analysis Of Solid Liquid Two Phase Flow Field In Mixed Flow Turbine Based On CFD

Although our country is rich in hydropower resources,there are many sandy water streams.Moreover,most of the turbines running in hydropower stations are designed under clear water conditions.When running in muddy water,the running conditions will be changed,and the turbine will be damaged seriously The three main performance indexes of turbine are efficiency,cavitation and stability.To a great extent,it depends on the three-dimensional turbulent flow inside the turbine.The essence of the muddy water flow is solid liquid two phase flow.Therefore,it is necessary to study the characteristics of solid liquid two phase flow inside the turbine.With the rapid development of computer technology and computational fluid dynamics,some numerical simulation software has been successfully applied to the analysis of the internal flow characteristics of the turbine.In this paper,a mixed flow turbine is taken as an example to study the internal solid liquid two phase flow with the help of the commercial numerical simulation software Fluent.The whole flow passage of the Francis turbine volute,guide vane and runner and draft tube,which is the core of the energy conversion wheel rotating parts,and guide vanes,tail pipe noise interference,interaction,mutual influence,so the solid-liquid two-phase flow numerical simulation of the whole passage,is of great significance.In order to understand the characteristics of the solid liquid two phase flow inside the turbine,the k-? model is used in this paper on the single phase water medium based on the full flow channel.The Euler model is used to calculate the solid liquid two phase medium containing particles.The characteristics of the internal flow of the two conditions are compared and analyzed,and some constructive suggestions are put forward.The main work is as follows:1.Pro/E 3D modeling software is used for 3D modeling of the whole flow passage of the turbine,and the Fluent's preprocessing software ICEM is used to mesh the whole flow path of the Francis turbine.2.taking pure water medium as an example,the selection of numerical calculation models,the definition of boundary conditions and materials,the processing methods of rotational regions,the solution methods and the selection of discrete schemes are analyzed.Especially,the particularity of numerical calculation is emphasized for solid liquid two phase media.3.under the water medium,the standard k-? model is used to calculate the three-dimensional flow field of the full flow channel of the hydraulic turbine under six working conditions.4.for the solid liquid two-phase medium,the Eulerian model is adopted for the multiphase flow model.The k-? mixture model is adopted for turbulent flow.The flow field of the whole flow passage of the turbine is calculated under six working conditions when the particle diameter and volume concentration are constant.5.Compare the flow field calculation results of different working conditions under the two different media and find the flow law.