金属垫片密封连接的泄漏率计算

金属垫片密封是压力容器和管道中常见的连接型式,其失效极少是因强度不足引起的,泄漏是连接系统失效的主要原因。在金属垫片泄漏模型基础上,考虑垫片接触应力分布不均匀对泄漏通道的影响,推导了变截面泄漏通道的泄漏率计算公式,此公式将泄漏率、垫片接触应力、介质压力和密封表面分形参数联系在一起,因而使以最大允许泄漏率为准则的金属垫片密封连接设计以及紧密性评价成为可能。

Leakage rate calculation of metallic gasket connections

Metallic gasket sealing connections are widely used in pressure vessels and piping.The failure of most sealing systems is caused not by the strength of flanges but by the leakage of the connections.Based on the leakage model of metallic gaskets the effect of the non-uniform distribution of the contact stress of gasket on the shape and size of the leakage passage was investigated, and the equation for calculating the leakage rate of the sealed medium flowing through a leakage passage with variable cross-section was derived.Such an equation described the relationship among the leakage rate of the connection，the contact stress of gasket，the medium pressure and the fractal parameters of the sealing surface.The research results make it possible to design the metallic gasket connections based on the criterion of the maximal allowable leakage rate and to assess the tightness of the connections.