FRACTAL ANALYSIS OF THE PENETRATION FLOW THROUGH MICRO-NANO POROUS GASKETS WITH EFFECTS OF SLIPPAGE AND STRESS-SENSITIVITY

Abstract

The airtightness of non-metallic sealing structures undergoing harsh conditions is very crucial to the reliability of equipment in many industrial fields. In this study, the gas penetration through a non-metallic sealing material (NSM) with micro-nano porous structure under stress was investigated in detail based on the transport theory of fractal porous media. A complete theoretical model for predicting the stress sensitivity of the gasket permeability was developed, in which the slippage effect was of concern due to very fine pore size. The permeability of a flexible graphite gasket under different stresses was numerically predicted via scanning electron microscopy (SEM) and image processing. The influencing factors on the permeability of the NSM were analyzed quantitatively and good agreements with existing experimental results demonstrate the validity of the proposed model. Since the effects of the pore-size distribution and flow pattern regime were taken into account, the parameters of the model had a clear physical meaning and the model was suitable for determining the mechanism of penetration leakage through the NSM. In addition, the model could also be used for the analysis of other tight porous media with complex microstructure under stress deformation.