考虑自旋运动的弹性流体动力润滑热效应分析

Analysis on Thermal Effects of Elastohydrodynamic Lubrication Considering Spinning

为有效地评估润滑油膜热特性,采用Eyring非牛顿流体,建立考虑自旋运动的点接触热弹流润滑模型,应用多重网格技术和逐列扫描技术进行数值仿真,并讨论滑滚比、速度、特征剪应力、最大Hertz压力和自旋因数对弹流润滑性能的影响。结果表明:考虑自旋运动时,中高载时用非牛顿流体得到的油膜温度明显低于牛顿流体的油膜温度;自旋运动使膜厚及温度分布失去了原有的对称性,且对于较低剪切应力的非牛顿流体,自旋运动使温度分布的不规则性更明显;随载荷的增加,摩擦因数开始时几乎线性增加,而随着载荷的增加热效应也逐渐增强,因此摩擦因数在达到最大值后出现下降的趋势;随着自旋因数增加,膜厚及温度分布的不对称性增强,温度最大值升高,且向一侧偏移。

In order to effectively assess the thermal characteristics of lubrication film,using the Eyring non-Newtonian fluid,the thermal elastohydrodynamic lubrication model considering spinning was built,and numerical simulation was carried out with multi-grid method and column by column sweeping technique. The effects of the slid-roll ratio and speed,the characteristics of shearing stress,the maximum Hertzian pressure and the spinning factor on the elastohydrodynamic lubrication performances were discussed. Results show that,the main difference between non-Newtonian and Newtonian fluid is that the oil film temperature for the non-Newtonian fluid is significantly lower than that of Newtonian fluid for the moderate or high load considering spinning. The symmetry of distribution of the film thickness and temperature disappears because of spinning. For the non-Newtonian fluid with lower characteristic shearing stress,the irregularity of the temperature distribution is more obvious due to the spinning. With the increase of load,the friction coefficient is firstly increased linearly,while the thermal effect is also gradually strengthened with the load increasing,so the friction coefficient has a decreasing trend after reaching the maximum value. With the increase of spinning factor,the asymmetry of film thickness and temperature distribution are increased,the highest temperature goes up and moves towards one side.