Study On Flow Transmission Characteristics Of Hydro-viscous Clutch In Tracked Vehicle

In order to simulate the flow field of oil film more precisely, obtain the characteristicsof torque transmission caused by shear stress. analyze property of the fluid caused by shearstress, double arc oil grooves friction pairs of hydro-viscous clutch in vehicle has beenstudied, combining method of numerical simulation and experimental study overall.Analyzing the heat translation of oil, and basing on considering the thermal affection, thephenomenon of cavitation and gas-liquid two-phase flow are studied. In addition, law studyof torque caused by shear stress are performed, with the affect factor include oil filmthickness, input speed, oil temperature in inlet and flow provided.The dynamic model for the fluid in the fiction pair is obtained based on CFD software.The heat transfer in the friction pair is analyzed, to gain the simulation results which arecloser to the experimental results in the boundary condition of convective heat transfer. Inthe same boundary condition, the influence of viscosity-temperature properties ontemperature and pressure fields of the fluid in friction pair and the impact of variable inputspeed, inlet temperature, film thickness and fuel supply on transfer torque of the fluid infriction pair are also analyzed.Based on the heat transfer model, considering liquid-vapor changes, turbulence,surface tension, presence of non-condensible gas, cavitation model is built. Pressure fieldand temperature field are acquired by compute, in addition can obtain distribution of vaporand the effect on the fluid torque caused by shear stress of the film thickness, input speedand the oil flow provided.Based on CFD software, using free surface (VOF) model, for the high-speed conditionof vehicle powertrain, the fluid in friction pair is numerically simulated, the two-phase fluidfield is analyzed. The regional distribution and evolution of two-phase are finally obtained.Besides, the fluid shear torque between fictions in different input speed and fuel supply arecomparatively analyzed. The research shows that, two-phase region is mainly affected byhydrodynamic and hydrostatic effect of fluid, the higher the input speed, the bigger the airvolume fraction, while the air volume fraction is getting smaller when the fuel supply isgreater.Finally, the experimental bench of hydro-viscous speed clutch performance isestablished, and the friction torque transfer characteristics and speed performance are compared with experiments, which verify the reasonableness of the prediction model.