混合流态下鲨鱼皮织构滑动轴承静特性分析

Analysis on Static Characteristics of Shark Skin Textured Journal Bearings Under Mixed Flow

轴瓦表面的织构会导致油膜厚度分布不均匀,整个流场中雷诺数差异较大,形成紊流和层流并存的混合流态。另外在高速运转工况下润滑油温度会大幅升高,从而影响其黏度及轴承承载能力等性能。鉴于鲨鱼皮结构在减阻、防污方面的成功应用,根据鲨鱼的盾鳞结构抽象建立了类鲨鱼皮二维织构的数学模型;同时考虑紊流以及油膜温度的作用,将类鲨鱼皮织构用于滑动轴承轴瓦形面的设计上,从鲨鱼皮织构的周向和轴向分布位置、织构深度、转速4个方面,对比分析了鲨鱼皮织构与球坑以及圆柱坑织构对滑动轴承静特性的影响。结果表明:1)织构位置分布对径向滑动轴承的性能影响非常大;2)不同织构深度下,鲨鱼皮织构始终表现出良好的减摩效果;3)高速紊流状态下的鲨鱼皮织构滑动轴承相比其他轴承减阻效果更加明显。

Due to the existence of surface texture of bearing bush,the oil film thickness distribution is not uniform,and the difference in Reynolds number is great in the whole flow field,resulting in the mixed flow state of turbulent flow and laminar flow.In addition,under the condition of high-speed operation,the temperature of lubricating oil will increase significantly,thus affecting its viscosity,load capacity of bearings and other properties.In view of the successful application of shark skin structural model in drag reduction and antifouling,a mathematical model of shark skin 2D texture is established abstractly based on placoid scale structure of sharks.Considering the effect of turbulent flow and oil film temperature,the shark skin texture is applied to design of bush shape of journal bearings.From four aspects,such as circumferential and axial distribution positions,texture depth of shark skin texture and rotational speed,the effects of shark skin texture,ball pit and cylindrical pit shape texture on static characteristics of journal bearings are compared and analyzed.The results show that:1)the distribution of texture positions have a great influence on performances of plain journal bearings;2)under different texture depths,the shark skin texture always shows a good friction reducing effect;3)the drag reduction effect of shark skin textured journal bearings under high speed turbulent flow is more obvious than that of other bearings.