Full Flow Simulation Study And Pressure Pulsation Analysis Of Francis Turbine

Turbine is one of the important equipment of hydropower station,with the country to actively develop large-scale hydropower construction,Francis turbine will undoubtedly become the most widely used a turbine.In this paper,the mixed flow turbine of a hydropower station is taken as the research object.Through the three-dimensional modeling of the turbine,the computer is used as the experimental platform,and the whole flow path simulation method is used to study the internal flow of the turbine.Firstly,the background and significance of this paper are briefly introduced.The research methods of internal flow of hydraulic turbine are introduced,and the research status of flow simulation of Francis turbine at home and abroad is briefly presented.Secondly,the basic theoretical knowledge used in the introduction and calculation of CFD software is discussed,and the advantages and disadvantages of several turbulence analysis and calculation methods are discussed emphatically.Then,we use the professional CAD software Pro/Engineer to model the three-dimensional components of the whole flow of the turbine,and use the professional grid division software ICEM to divide the whole channel grid to realize CAD/CFD technology Of the fusion,volute,guide vanes,runners are non-structural grid division,the tail pipe part of the structural grid.Finally,the simulation results are calculated based on the simulation results of 8 different working conditions of the turbine,and the calculation results of each overcurrent component are analyzed.The velocity field of the volute,the movable guide vane,the runner and the draft tube are analyzed by using the Realizable model as the simulation model.And the pressure field is distributed,and the unsteady state simulation is carried out.Finally,the pressure pulsation distribution and vortex distribution of the draft pipe are obtained,and the pressure pulsation characteristics are analyzed.The reason of the pressure pulsation is deduced,Which provides a theoretical basis for the stability of the unit in the actual project,and makes a preliminary exploration to find out the relationship between the operation and the pulsating strength of the draft pipe under different working conditions.