Transferred Torque Characteristics In Hydro-viscous Clutch Based On Cavitation Effect

As a new type of speed regulating device,Hydro-viscous Clutch relys on the viscous shearing of oil film between multiple groups of friction pairs to transfer power,which is widely used in the mining,metallurgy and water conservancy machinery,with significant energy saving effect.The integrity of the oil film in the process of transmission of Hydro-viscous Clutch is the key to the stability of the power transmission.Taking the radial groove as research object in this paper,and based on the cavitation effect of oil film,studied the effects of oil film thickness,rotational speed and flow supply on the flow field characteristics and output torque.Main contents are as follows:During the stage of pure oil film shear,choosing the oil film between a pair of friction pairs as research object,established mathematical model of the flow field characteristics.Brought out the distribution of the flow field characteristics of speed,pressure and flow through the application of distribution analysis method,and analyzed the influences of oil viscosity,rotational speed and flow supply on the radial velocity of oil.Based on the boundary condition of cavitation Reyonlds,built the model of equivalent radius of the oil film,and calculated the model of oil film torque.On the basis of cavitation effect of oil film,established the model of VOF,conducted numerical simulation of the flow field characteristics of oil film between the friction pairs,and analyzed evolution rule of the air-oil phase area.By changing input speed,flow supply,inlet temperature and oil film thickness,revealed the changing conditions in the air-oil phase area and of the transmission torque.On the basis of cavitation effect of oil film,built oil film simulation model with multiple groups of different parameters of oil groove,analyzed the distribution of shearing stress,pressure,and volume of gas on the surface of oil film.Found that the dynamic pressure effect generated by oil groove can increase the viscous shearing force on the wall,and found the conditions of the total pressure producing negative torque.The results of the studies showed that the speed,oil film thickness and the parameters of oil groove have some influence on the cavitation of oil film.At last,by comparing the experimental data of clutch transmission torque of the General Technological Center,the rationality of the transmission torque model have been verified under the condition of the cavitation of oil film.