接触式机械密封界面泄漏机理研究的关键科学问题

Key scientific problems for studying leakage mechanism of contact mechanical seal interface

密封界面的泄漏机理是机械密封研究与应用的焦点问题之一,涉及泄漏通道表征、粗糙表面的接触力学模型、界面微观形貌变化以及介质流体在泄漏通道中的流动阻力等问题。回顾了近几十年国内外接触式机械密封泄漏通道模型的研究,深入分析了G-W模型、M-B模型和Persson模型3种粗糙表面接触力学模型的贡献和存在的问题,提出了一种基于逾渗理论的泄漏通道新模型;探讨了密封界面的分形参数、泄漏通道的流动阻力以及密封界面的有限尺寸效应对泄漏特性的影响,指出孔隙连通贯穿界面和流体流经贯穿通道的流动阻力小是密封界面产生泄漏的成因,以及泄漏通道的形成和泄漏通道内的流体流动特性是泄漏机理研究的主要方向。

As one focal point for research and application of mechanical seals, leakage mechanism of seal interface involves characterizing leakage channels, modeling contact mechanics of rough surface, exploring morphological changes of seal interface and defining fluid flow resistance in leakage channels. The development of leakage channel models of contact mechanical seals in recent decades was reviewed. After analyzing contributions and problems of G-W, M-B, and Persson models of rough surface contact mechanics, a new percolation channel model was proposed. The effects of fractal parameters of seal interface, fluid flow resistance of channels, and limited size of seal interface on leakage characteristics were discussed. It was noteworthy to point out that leakage occurrence at seal interface was mainly due to pore connection across interface and low flow resistance of fluid through interface channels. Future studies on leakage mechanism will be formation of leakage channels and characteristics of fluid flow in these channels.