计入非牛顿效应的曲轴轴承的混合润滑分析  

Analysis of Crankshaft Bearings in Mixed Lubrication Including Non Newtonian Effects

作　　者：张朝[1] 张直明[1] 

机构地区：[1]上海大学机械电子工程学院,上海200072

出　　处：《内燃机学报》1999年第3期303-307,共5页Transactions of Csice

摘　　要：分析了剪切变薄的非牛顿流变学特性和两表面都具有的纵向、横向和各向同性粗糙度对动载有限宽径向滑动轴承性能的综合影响。 Ｃｈｒｉｓｔｅｎｓｅｎ 的粗糙表面流体动力润滑的随机模型和 Ｇｒｅｅｎｗ ｏｏｄ Ｔｒｉｐｐ 接触压力的计算模型用于处理粗糙问题，并考虑了磨合对粗糙高度分布的影响。幂律流体模型用来表征剪切变薄的流变学特征，质量守恒的油膜破裂算法用于雷诺方程的求解。计算结果表明，粗糙度总是减小最小名义油膜厚度，并使油膜压力在接触区剧烈振荡，其幅值大于光滑表面时周期内的最大名义油膜压力。名义最小油膜厚度在纵向粗糙时最大，横向粗糙时最小。粗糙纹理相同时，相同粗糙结构下的名义最小油膜厚度在牛顿流体时大于不同粗糙结构时的相应值，在非牛顿流体情况下，结论相反。混合润滑的轴承性能受粗糙纹理和结构、幂律指数、轴承几何结构、轴颈质量及运行工况的综合影响。The comprehensive effects of non Newtonian shear thinning characteristics and two sided purely longitudinal,transverse and isotropic roughness on dynamically loaded finite journal bearings in mixed lubrication are numerically analyzed.Christensens stochastic model of hydrodynamic lubrication of rough surfaces and the asperity contact model developed by Greenwood and Tripp are used to treat the roughness problem.Running in effect on roughness height distribution is considered.Shear thinning is characterized by the Power law fluid model.A mass conserving cavitation algorithm is used to solve the modified Reynolds equation.It is shown that roughness always decreases the minimum nominal film thickness and increases oscillations of the maximum nominal film pressure in the mixed lubrication regions,resulting in its maximum values bigger than those in the smooth cases.The minimum nominal film thickness is biggest in the longitudinal roughness and the smallest in the transverse case.For the same roughness texture,in the Newtonian fluid,the minimum nominal film thickness of the same roughness structure is bigger than that of the different roughness structure,and it is opposite in the shear thinning case.The bearing performances of crankshaft bearings in mixed lubrication are affected seriously by the roughness texture and structure,power law index,features of the nominal geometry,journal mass,and operation conditions.

关 键 词：混合润滑 径向轴承 表面粗糙度 流变学 内燃机 

分 类 号：TK403[动力工程及工程热物理—动力机械及工程]