非对称结构表面织构对滑动轴承摩擦性能的影响

Influence of Asymmetric Surface Texture on Friction Performance of Journal Bearings

为揭示织构凹坑方式对径向滑动轴承摩擦性能的影响,基于气液两相流理论,建立径向滑动轴承腔内油气两相流数值计算模型。将传统普通织构改进为出入口呈阶梯状的非对称织构,定义出入口壁面高度比值H为非对称因数,采用SIMPLEC算法进行求解,分析非对称因数对凹槽织构单元流体域内流场的影响,探讨径向滑动轴承不同位置织构、不同转速下非对称因数对摩擦学性能的影响。结果表明:凹槽织构排布于收敛楔入口能够有效提高摩擦学性能;由于流场速度和方向的变化以及织构凹坑出口处产生的双涡旋的影响,不同H值上壁面压力均大于对称织构与无织构工况;随着转速的提高,轴承腔内油相体积分数下降,H=0.25时承载能力最高,摩擦因数最小。因此,研究非对称表面织构对改良径向滑动轴承的润滑效果具有重要意义。

In order to reveal the influence of the groove texture pattern on the friction performance of radial journal bearing,a numerical model of oil-air two-phase flow in the cavity of radial journal bearing was established based on the air-liquid two-phase flow theory.The conventional texture was modified into an asymmetric texture with stepped inlet and outlet,the inlet and outlet wall height ratio H was defined as asymmetric factor,the model was solved by SIMPLEC algorithm.The influence of the asymmetrical factors on the flow field in the fluid domain of groove texture element was analyzed,and the influences of asymmetrical factors on tribological properties of journal bearings at different position textures and different rotational speeds were investigated.The results show that the groove texture arrangement at the convergent wedge inlet can effectively improve the tribological properties.The pressure on the upper wall with different H values is greater than that of the symmetric textured condition and the non-textured condition,the reasons are the change of flow velocity,direction and the generation of double vortices at the outlet of the textured pit respectively.With the increase of the rotating speed,the volume fraction of oil phase in the bearing cavity decreases.When H=0.25,the bearing capacity is the highest and the friction coefficient is the minimum.Therefore,it is of great significance to study the asymmetrical surface texture for improving the lubrication effect of radial sliding bearings.