密封结构中粗糙表面特征对其气密性的影响

The Influence of Characteristic of Rough Surface on Gas Sealing Performance in Seal Structure

基于Gauss分布函数和指数自相关函数关系建立三维粗糙表面的数学模型,获得密封面的数值粗糙表面。进而在三维数值粗糙表面的基础上,采用流动数值分析方法,对金属垫片密封结构的气密性进行了研究,分析表面粗糙度、应力以及材料力学特性等相关参数对泄露率的影响。为构建泄漏率表达式,引入流量因子表征现有模型泄漏率与平行圆板模型的差异,流量因子是膜厚比的函数。该工作实现了静接触密封结构泄漏特性定量评估的数值分析方法,对各种硬密封结构的高精度设计有着重要指导意义。

A mathematical model based on Gauss distribution function and exponential autoeorrelation function is built to describe the geometry morphology of real rough surface, and a numerical 3D sealing rough surface is generated according to the mathematical model. The leakage gap of a metal gasket seal structure is constructed by using two contact rough surfaces and its gas sealing performance is numerical analyzed. The influence of those relative parameters, such as roughness, stress and material mechanical characteristic, on the leakage rate is studied. To construct the expression of the leakage rate base on these numerical results, the flow factor is introduced to indicate the difference between the results obtained in this numerical work and that of the ideal parallel round plate leakage model. The flow factor is dependent on the ratio of the gap height and the surface roughness. Current work is dedicated to find a numerical method to quantities evaluate the leakage characteristics of static contact seal construction and had important instruction significance for their high precision design.