局部凹坑织构化径向滑动轴承流体动力润滑数值分析

Numerical Analysis of Hydrodynamic Lubrication of Partially Textured Surfaces with Dimples for Journal Bearing

目的探究局部凹坑织构化表面对径向滑动轴承流体动力润滑的影响。方法基于雷诺边界条件和Reynolds方程,建立凹坑织构化径向滑动轴承表面流体动力润滑理论模型,采用Gauss-Seidel松弛迭代方法数值求解,获得润滑油膜的压力分布和承载能力,分析其润滑油膜承载机制,探讨凹坑几何参数和分布规律对油膜承载力的影响规律。结果理论模型的数值解与经典理论的数值解误差较小,能有效分析轴承的流体动压润滑特性。当偏心率较大时,摩擦力的上升幅度也变大,在轴承承载区进行凹坑织构化处理能明显减小摩擦力,并且随着凹坑深度的增大,摩擦力减小,可见凹坑起润滑减摩的作用。油膜承载力随着偏心率的增大而增大,通过凹坑织构的"楔形效应"能够改善非承载区的油膜压力,存在最佳凹坑深度使得轴承达到流体动力润滑最佳状态。摩擦力随着面积率的增大而增大,特别是在偏心率较大时,润滑减摩效果较为明显,面积率对油膜承载力影响不大。将织构布置在径向滑动轴承的不同区域,其中当织构完全在下半瓦(压降区)时,织构能明显增大油膜厚度,产生油膜压力,有效降低摩擦力,提升承载力。结论凹坑织构能明显改善径向滑动轴承流体动力润滑性能,合理设计轴承的偏心率,合适的织构参数与分布位置,能使流体动力润滑效果最佳。

The work aims to investigate the textured surface with dimples on hydrodynamic lubrication performance of journal bearing surface.A theoretical model,basing on Reynolds boundary condition and Reynolds equation,on hydrodynamic lubrication of textured surface with dimples for journal bearing considered is presented.The influence on the hydrodynamic lubrication property of textured surface with dimples is analyzed via the pressure distribution and load capacity of film achieved by Gauss-Seidel relaxation iteration method.The influence of dimples geometric parameters and distribution law on film bearing capacity is discussed.The numerical solution of the theoretical model established in this paper is less error than that of the classical theory,which can effectively analyze the hydrodynamic lubrication characteristics of bearings.When the eccentricity is large,the increase range of friction is also larger.Dimple texture treatment in the bearing loading area can significantly reduce the friction force,and with the increase of the depth of the dimple,the friction force decreases,so it can be seen that the dimple plays a role of lubrication and friction reduction.The film bearing capacity increases with the increase of eccentricity.The film pressure in the non-bearing zone can be improved through the"wedge effect"of the dimple texture,and the optimal dimple depth can make the bearing reach the optimal state of hydrodynamic lubrication.The friction increases with the increase of area ratio,especially in the case of large eccentricity ratio,the lubrication antifriction effect is more obvious,and the area ratio has little influence on the bearing capacity of oil film.The texture is arranged in different areas of journal bearing.When the texture is completely in the lower half tile,the texture can significantly increase the oil film thickness,generate oil film pressure,effectively reduce friction,and improve the bearing capacity.Reasonable design of eccentricity,appropriate texture parameters and distribution position can make hydrodynamic lubrication effect best.