工作油液温度对液力变矩器性能影响计算流体力学分析及试验研究

Research on Effect of Working Oil Temperature for Hydraulic Torque Converter Performance Using CFD and Test

采用计算流体力学(Computational fluid dynamics,CFD)仿真分析和台架试验手段相结合的方法,分析工作油液温度对变矩器原始特性参数(变矩比k、能容系数λ和效率η)、泵轮所受转矩Tp和涡轮所受转矩Tt的影响。由于工作油液温度主要影响油液的密度和黏度,所以采用CFD仿真分析方法研究单变量变化情况下,工作油液密度和黏度分别对液力变矩器性能的影响。结果表明,工作油液温度对变矩器性能影响体现在油液密度和黏度耦合交互的综合影响,并且黏度影响起主导作用;随着工作油液密度的减小,λ、k和η不受影响,Tp和Tt逐渐减小。随着工作油液黏度的减小,Tp、Tt、λ、k和η均逐渐增加;随着变矩器工作温度的增加,工作油液黏度和密度均有所减小,Tp和λ逐渐下降,Tt变化很小,k和η有所提高。因此,在不影响密封件密封要求及油液寿命的前提下,应尽量提高液力变矩器工作油液温度,可以改善其工作性能。

Using computational fluid dynamics（CFD） and test methods,the influence of the working oil temperature on the original characteristic parameters of torque converter（torque ratio κ,capacity coefficient λ,and efficiency η）,pump torque Tp and turbine torque Tt.Since working oil temperature mainly influences the density and viscosity of the oil,using CFD simulation analysis methods,investigate the influence of the single variable of density or viscosity on the performance of torque converter.The results show that the working oil temperature influence on torque converter performance is the result of oil density and viscosity changing,and viscosity influence plays a leading role; As working oil density decreasing,λ,κ and ηare not affected,Tp and Tt are decreasing.As working oil viscosity decreasing,Tp,Tt,λ,κ and ηare all increasing; As temperature increasing,viscosity and density of working oil are all decreasing,Tp and λ are decreasing,Tt is barely changed,but k and ηare increasing.Therefore,under the requirement of the sealing and working oil life time,torque converter working temperature should increasing as high as possible to improve its performance.