基于CFD分析的表面织构润滑计算适用方程研究

Applicable Equation Study of Lubrication Calculation of Surface Texture Based on CFD Analysis

为提出N-S方程和Reynolds方程在建立表面织构润滑计算模型时适用范围的判据,对流体润滑条件下织构表面的流体动力学表现进行研究。采用求解基于N-S方程的表面织构润滑计算模型的方法研究惯性项对织构表面流体动力学性能的影响规律,并通过改变流体域典型长度尺寸l与摩擦副间隙h0的比值对Reynolds方程的适用范围进行探讨。结果表明:当l/h0<46时,惯性项的影响不可忽略,必须采用N-S方程进行织构表面的理论建模;惯性项的影响越显著,织构表面的承载力越大,而流体域中涡流也越容易产生,因而在进行表面织构参数设计时,使惯性项影响增大的同时要尽量避免织构内部涡流的产生;当l/h0≥46时,惯性项的影响可以忽略不计,可以采用Reynolds方程代替N-S方程建立流体润滑条件下表面织构的润滑计算模型,但此时必须考虑空化现象对压力分布的影响。研究结果为表面织构的设计及理论建模提供了一定的参考。

In order to compare the fluid dynamic performance of textured surfaces based on N-S equation and Reynolds equation under hydrodynamic lubrication,respectively,and then put forward a criterion about the scope of the two equations in establishing the lubrication computation model of surface texture,the influence of inertia on fluid dynamic characteristics is studied by solving the lubrication computation model of surface texture based on N-S equation and the scope of Reynolds equation is also discussed by changing the ratio of typical fluid domain length l to clearance of the friction pairs h0.The results show that the influence of inertia cannot be neglected when l/h0 is less than 46 and N-S equation must be adopted;the more significant the influence of inertia,the greater the load capacity of the surface texture and the easier the liquid swirl to produce,thus the influence of inertia should be increased and the emergence of the liquid swirl should be avoided in parameter design of surface texture;the influence of inertia can be neglected when l/h0 is not less than 46 and Reynolds equation can be adopted instead of N-S equation,however,the influence of cavitations on pressure distribution must be considered.The results provide a certain reference for the design and modeling of surface texture.