Contact-Leakage Characterization of Metal Sealing Rings Using Fractal Theory and Finite Element Analysis

This paper presents an innovative approach to analyzing metal O-ring sealing performance by integrating fractal theory with fluid mechanics to model interface micro-convex characteristics. Unlike conventional methods, this approach more accurately represents the actual surface morphology of the sealing interface, enabling more precise leakage predictions. The research combines finite element analysis of the sealing surface contact states with hydrodynamic simulations of microchannel leakage behavior. Through experimental validation, the impact of sealing medium, inlet pressure, surface roughness, and compaction load on the contact area and leakage rate is systematically investigated. The key findings reveal that gases exhibit higher leakage propensity than liquids due to their superior fluidity, and the seal leakage rate increases with inlet pressure, reaching 18.86×10-5 kg/s. Reducing surface roughness enhances interface contact and minimizes micro-leakage gaps, thereby improving sealing performance. Additionally, thresholds for compaction load are identified, beyond which further load increases result in negligible sealing gains. By bridging interface contact mechanics with microchannel leakage dynamics while accounting for realistic surface morphology, this work provides a framework for improving metal sealing ring performance prediction and optimization.