椭圆微孔截面形状对机械密封动力润滑性能的影响

摘要

A three-dimensional hydrodynamic lubrication model of the incompressible Newtonian fluid between two seal faces with single microdimple was built based on the full Navier-Stokes equation,the hydrodynamic lubrication of mechani-cal seal surface with the different bottom shapes of ellipse microdimple was studied,and the effects of different sections (rectangular,trapezoidal,triangular)of ellipse microdimple on load-carrying capacity,friction force and friction coeffi-cient were analyzed.The results show that under the condition of the other factors with constant values,the microdimple with rectangular section has the best dynamic lubrication performance at the ratio of microdimple depth and end face clear-ance H* <0.8,the trapezoidal section is the best choice when 0.8≤H* <1.8,and the triangular section is preferred for selection at H*≥1.8.When the microdimple inclination angle α=45°,the dynamic lubrication performances get optimal value for all ellipse microdimples with different section shapes.Further more,the trapezoidal section microdimple has a better hydrodynamic lubrication performance compared to the other section microdimples under the condition of different inclination angles.When 1.5≤γ<2 (γis the ratio of length and width of microdimple ),the ellipse microdimple with trapezoidal section has the best dynamic lubrication performance,but the rectangular section ellipse microdimple is the best at γ>2 .%基于Navier-Stokes方程，建立单一椭圆型微孔端面不可压缩牛顿流体的三维CFD动力润滑模型，研究不同截面形状椭圆微孔机械密封的动力润滑性能，分析截面形状为矩形、梯形和三角形的椭圆微孔对端面液膜承载力、摩擦力和摩擦因数的影响。结果表明：在微孔其他参数恒定情形下，微孔深度与端面间隙比值H*＜0.8时，矩形截面微孔的动力润滑性能占优，0.8≤H*＜1.8时梯形截面微孔的动力润滑性能占优， H*≥1.8时三角形截面微孔的动力润滑性能最好；微孔倾斜角为45°时3种截面形状下都取得了最好的动力润滑性能，且梯形截面动力润滑性能最好；微孔长宽比1.5≤γ＜2时梯形截面形状的微孔端面动力润滑性能最好，但当γ＞2时矩形截面形状的微孔端面动力润滑性能最好。