线接触弹流润滑综合数值分析

General Analysis of Line Contact Elastohydrodynamic Lubrication

应用多重网格法和多重网格积分法数值求解了Newton流体和Ree-Eyring流体线接触等温和热弹流润滑问题,分析了滑滚比对摩擦因数的影响,指出了润滑油的流变性和热效应对线接触弹流润滑油膜粘度的影响,以及不同滑滚比时压力、膜厚和温度的分布规律。结果表明:等温润滑时的摩擦因数随着滑滚比的增加而增加,热弹流润滑时的摩擦因数随着滑滚比的增加先增加后减小,热效应和非牛顿流体的剪稀作用均会使润滑油的等效粘度降低,从而影响摩擦因数;热效应的存在使油膜变薄,且在所讨论的工况条件下Newton流体的膜厚比Ree-Eyring流体的稍薄,热效应使第二压力峰变矮,且Ree-Eyring流体的第二压力峰矮于Newton流体的第二压力峰;纯滚动时,Ree-Eyring流体的温度比Newton流体的温度高,有滑滚比时,Newton流体的温度比Ree-Eyring流体的温度高,且油膜的温度随滑滚比的增加而增加。

The isothermal and thermal line contact elastohydrodynamic lubrication with Newtonian and Ree-Eyring models were investigated numerically with the muhigrid method and the multi-level multi-integration method. The influence of the slide-roll ratio on the frictional coefficient was analyzed,and the influence of the rheological property and the thermal effect on the viscosity of the oil and the distributions of the pressure ,film thickness and temperature with various slide-roll ratios were indicated. The results show that,as the slide-roll ratio increases,the frictional coefficient predicted by the isothermal solutions increases monotonously, whereas the frictional coefficient predicted by the thermal solution first increases and then decreases. Both the thermal and the non-Newtonian shear thinning effects can reduce the effective viscosity of the lubricant,so they affect the frictional coefficient. The existence of thermal effect can reduce the film thickness,and the film thickness predicted by the Newtonian theory is a little smaller than that predicted by the Ree-Eyring theory under the discussed operating conditions, meanwhile, thermal effect can reduce the height of the pressure spike, and the spike obtained by the Ree-Eyring solution is lower than that obtained by the Newtonian solution. Under pure roiling conditions, the film temperature offered by the Ree-Eyring solution is higher than that offered by the Newtonian solution, under the sliding/rolling conditions, however, the later is higher than the former. Furthermore, both the Newtonian and Ree-Eyring solutions indicate that, the film temperature increases as the slide-roll ratio increases.