表面织构的深度影响润滑油膜承载能力的机制研究

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采用基于N―S方程的CFD方法，研究最小油膜厚度为4μm时圆弧凹槽表面微织构深度的变化对动压润滑效果的影响，并深入探讨其机制。结果表明，在一定的工况条件下，凹槽深度不同，其承载性能存在一定的差异，当凹槽深度小于4μm时，随织构深度的增加其承载能力逐渐增强，当凹槽深度大于4μm时，随织构深度的增加其承载能力逐渐减弱，即深度值在4μm左右时油膜的承载能力最强。分析发现，织构深度的变化改变了润滑油流场的流动，深度增大到某个值时润滑油开始出现逆流现象，随着凹槽深度的增加，逆流区变大；逆流的存在削弱了织构的承载能力；速度不影响润滑油的流动走向，但会影响承压能力的大小；织构截面形状对润滑油的流动走向有影响，但对织构底部形成漩涡的规模大小影响不大，对润滑油膜承压能力影响不大。 The influences of depth of arc-groove surface texture on the hydrodynamic lubrication of friction pairs were researched through CFD method based on N-S equation when the minimum oil film thickness is 4 μm and the mechanism was explored. The results show that, under a certain condition,load bearing capacity varies with the variation of arc-groove depth. When the depth of arc-groove is less than 4 μm the load bearing capacity will increase with the increase in arc- groove depth. But when the depth of arc-groove is more than 4 μm, the load bearing capacity will fall with the depth of arc- groove increasing. That is, the load bearing capacity of oil film is the best when the depth of arc-groove is about 4 Ixm. It is found that the variation of depth of surface texture changes the flow of oil. When the depth of arc-groove increases to a certain number, the backflow of oil appears. And the area of backflow becomes larger when the depth of arc-groove increases. The backflow decreases the load bearing capacity of surface texture. Velocity doesn＇ t change the flow of oil but the load bearing capacity. The cross section profile influences the flow of oil, and has little influence on the area of backflow and the load bearing capacity of oil film.