Study on drag torque characteristics of wet multiplate clutch under high-speed operating condition

In order to study the characteristics of the drag torque of wet multi-plate clutches at high speed, a mathematic model of the drag torque considering oil-gas two-phase flow was established. Based on the VOF two-phase flow model, the oil-film fluid simulation of the flow field was finished, and the distribution law of the volume fraction of the oil-gas phase changing with the speed was analyzed. The analysis results of the model and simulation show that under high speed condition, the oil and gas two-phase flow occupies most of the area in the flow field gap, and leads to the rebound trend of the high speed drag torque. Finally, the variation of the drag torque under different working conditions is studied through experiments, and the influence of lubricant temperature, flow rate, friction plate speed and clearance of friction pairs on the drag torque is analyzed. The improved drag torque model was compared with the experimental results. When the speed is greater than 2000 r/min, the average relative error of the drag torque is less than 15%, which significantly improves the accuracy of the drag torque prediction model, and lays a theoretical foundation for further research on the structure design and optimization of wet multi-plate clutch.