Study On Multi-field Coupling Simulation In Hydro-viscous Clutch Based On Cavitation Effect

In this paper,the oil groove structure as a double circular arc type hydraulic viscous speed control clutch in the research object,and the oil film flow field of friction pair was simulated by CFD finite element simulation software.Mostly the cavitation effect of oil film flow field and the coupling of multiple physical fields for friction pair are analyzed in order to simulate the working condition of the whole friction pair.In addition,the characteristics of the flow field and the torque transfer are studied in terms of the inlet oil temperature,input speed,oil supply,oil film thickness and other influencing parameters in the oil film flow field.Firstly,the boundary conditions was opening the energy equation and viscous dissipation heat,the thermal boundary conditions were determined,the heat transfer model was established,the suitable numerical solution equation and solution scheme were selected,and the preliminary flow field simulation was carried out for the oil film in the double circular groove.Therefore,to analyse the distribution law of the pressure field,the temperature field and the velocity vector field in oil film clearance of the friction pairs are analyzed.Besides,to get the influence law of oil supply quantity on oil film transfer torque capacity under different input speed.Secondly,considering the presence of gas,the cavitation model was established and the surface tension of oil film was prepared to obtain the influence of the input speed,oil supply and oil film thickness of the oil film flow field on the cavitation effect,as well as the influence of the cavitation effect on the temperature distribution and transfer torque characteristics of the oil film flow field.Finally,based on cavitation effect,the thermal fluid-solid coupling of clutch friction pair was simulated numerically.Furthermore,to analyse the maximum deformation,stress of the active,passive parts of the friction pair with the oil film thickness,the input speed before and after the cavitation.As a result,it is shown that the pressure in the oil film flow field is lower than the saturated vapor pressure of the working oil,and the total amount of gas produced in the flow field is small.The higher the rotation speed,is the larger the volume fraction of the gas will be,as well as the cavitation effect.The larger the oil supply,the smaller the gas volume fraction produced by cavitation,as well as the longer the cavitation effect.The larger the oil film thickness is,the larger the volume fraction of the gas produced by the cavitation will be,as well as the area will be.The lower the oil supply,the higher the rotation speed and the cavitation volume.When the input speed is low,the maximum deformation of the active and passive vane after cavitation is slightly higher.When the inputspeed is high,the cavitation effect on active and passive chips can be ignored.With the increased of the input speed,the maximum deformation and stress of the friction pair was increased.With the increase of oil film thickness,the total deformation was decreased correspondingly.