密封界面微孔结构的三维分形重构技术与泄漏特性

Three-dimensional Fractal Reconstruction Technique and Leakage Characteristics of Micro-pore Sealing Interfaces

基于分形粗糙表面的三维数值重构技术,对界面微孔结构的分形表征进行详细研究,并应用分形多孔介质输运理论构建界面泄漏机理模型,建立微观形貌与宏观泄漏率之间的理论关系式.用有限元分析法对单粗糙峰的接触变形进行模拟,获得最大孔径的变形位移,实现微观接触力学与微观泄漏模型的有效耦合.应用所提出的预测模型对金属垫片泄漏率进行计算,结果与已有实验结果相吻合.由预测模型可知,粗糙表面分形维数、特征尺度系数以及变形位移量对微孔几何结构影响显著,是影响界面泄漏率的关键因素.

Fractal characteristics of interface micro-porous structure is studied in detail with three-dimensional numerical reconstruction technology of fractal rough surface.An interfacial leakage mechanism model is built based on fractal porous media transport theory.Relation between microscopic morphology and macroscopic leakage rate is obtained.Contact behavior of a single asperity is simulated with finite element analysis,and deformation displacement of the maximum aperture is obtained.Effective coupling between microscopic contact mechanics and microscopic leakage model is achieved.Results of prediction model are in good agreement with experimental results in predicting metal gasket leakage rate.It is found that fractal dimension,and characteristic scale coefficient of rough surface and deformation displacement have great influence on geometry morphology of interface microporous structure,and therefore,are key factors of interfacial leakage rate.