考虑不流动层的点接触热弹流润滑的数值解

Numerical simulation to the point contact thermal elastohydrodynamic lubrication considering immobile layers

某些润滑油组分在润滑过程中会被吸附在固体表面上形成不流动层,另外,有时固体表面会镀上一层有机或无机膜,考虑到上述两种润滑状态,建立了加入不流动层的点接触弹流润滑热模型,进行了完全数值分析,得到了新模型下的压力分布与油膜形状,并研究了不同厚度的不流动层对润滑性能的影响.结果发现,当不流动层的厚度较小时,对润滑性能的影响较弱,可以忽略,但随着不流动层厚度的增加,影响逐渐增强,因而不可忽视.在温度场的计算中,引入逐列扫描法求解了固体、不流动层及油膜内各点的温度,从而验证了用数值方法求解考虑不流动层模型的可行性,并通过求解具体算例验证了其正确性.

Some molecules in the lubricating oil can be absorbed on the surfaces of solids in the process of lubrication, so that immobile layers can be formed. Furthermore, sometimes a layer of organic or inorganic solid film may be coated on each surface of the lubricated bodies, such solid film can also be considered as a kind of immobile layer. Taking into account these situations, a mathematical model of thermal elastohydrodynamic lubrication in point contacts inclusive of the immobile layers has been established, and full numerical solution has been achieved. The distribution of pressure and the profile of film thickness have been obtained. The influence of the thickness of the immobile layers on the behavior of lubrication has been investigated. It has been found that, when the thickness of the immobile layers is relatively small, its influence is weak so that can be ignored, however, as its thickness increases, its influence gradually becomes stronger, therefore can no longer be ignored. When solving the temperature field, a column-by-column sweeping scheme has been introduced into the algorithm, so that the nodal temperatures in both solids, both immobile layers as well as in the oil film can be obtained. Both the correctness of the established model and the feasibility of the algorithm for solving the model have been verified through the solution of some representative cases.