交叉沟槽织构化粗糙表面流体润滑数值分析

Numerical Analysis of Hydrodynamic Lubrication of Textured Surfaces with Cross-hatched Grooves

目的探究粗糙度对交叉沟槽织构化表面流体动力润滑性能的影响。方法基于质量守恒空化边界条件和平均流量模型的Reynolds方程,建立计入表面粗糙度效应的交叉沟槽织构化表面流体动力润滑理论模型,采用多重网格法进行数值求解,获得润滑油膜的压力分布和承载能力,分析粗糙度对交叉沟槽织构化表面流体润滑性能的影响规律。结果油膜承载能力随着沟槽宽度的增大而增大,表面粗糙度对油膜承载能力的影响随着沟槽宽度的增大而增大。存在最佳的沟槽深度和间距使得交叉沟槽所产生的流体动力润滑效应达到最强,表面粗糙度对油膜承载能力的影响在最佳沟槽深度附近最大,粗糙度对油膜承载能力的影响随着沟槽间距的增加而增大。油膜承载能力随着交叉角度的增大呈现先增大后减小的趋势,粗糙度对油膜承载能力的影响随着交叉角度的增加而增大。交叉沟槽的重叠系数对油膜平均压力几乎没有任何影响,粗糙度对油膜承载能力也几乎不受重叠系数的影响。结论在利用数值分析方法研究交叉沟槽织构流体动力润滑性能时,不能忽略粗糙度的影响,表面粗糙度在一定程度上抑制了交叉沟槽所产生的流体动力润滑效应,降低了油膜承载能力。

The work aims to investigate the effects of roughness on hydrodynamic lubrication of textured surface with cross-hatched grooves. Based on JFO boundary conditions and Reynolds equation of average flow model, the theoretical model considering roughness effect was established for hydrodynamic lubrication of textured surface. The multi-grid method was used for numerical solution to obtain the pressure distribution and bearing capacity of oil film, and analyze the influence of roughness on the hydrodynamic lubrication property of textured surface with cross-hatched grooves. The oil film bearing capacity and the influence of surface roughness on the oil film bearing capacity both increased with the increase of groove width. The optimum cross angle, groove depth and spacing contributed to the maximum hydrodynamic lubrication effect of the cross-hatched grooves. The influence of roughness on the hydrodynamic lubrication property of textured surface reached the maximum at the optimum groove depth and increased with the increase of spacing. The bearing capacity of the oil film increased first and then decreased with the increase of the cross angle, while the influence of roughness on the bearing capacity of the oil film increased with the increase of the cross angle. Overlap coefficient of the cross-hatched grooves neither affected the average oil film pressure nor had an impact on the influence of roughness on load capacity. Overall, the surface roughness can restrain the hydrodynamic lubrication performance to some extent and reduce the load capacity of the oil film, so the influence of roughness cannot be ignored when the hydrodynamic lubrication property of textured surfaces with cross-hatched grooves is studied by numerical analysis.