基于多孔介质理论的双粗糙面金属静密封泄漏模型

粗糙面微观几何形貌是影响静密封泄漏特性的重要因素。应用粗糙面的三维点云数据，将粗糙面进行离散化处理，进而将由双粗糙面构成的密封界面等效为三维逾渗栅格模型，基于多孔介质理论计算得到密封界面的孔隙率和渗透率，从而建立了一种双粗糙密封界面的泄漏率模型。搭建金属静密封泄漏率测量试验台，通过对环面金属静密封泄漏特性的试验研究，验证了该泄漏模型的有效性。利用该模型分析了表面纹理方向、粗糙面波动频率与材料特性对金属静密封泄漏特性的影响。结果表明：各向异性粗糙面构成的密封界面具有较好的密封性能；粗糙面波动频率越大，密封性能越好；低硬度材料易于实现有效密封；在重载情况下，粗糙面微观几何形貌对孔隙率与泄漏率的影响不显著。

Leakage Model of Metal Static Seal with Two Rough Surfaces Based on the Theory of Porous Medium

The micro-geometric topography of the rough surface is an important factor affecting the leakage characteristics of static seals. According to the point cloud data of the rough surface, the rough surface is discretized, and the sealing interface consist of two rough surfaces is equivalent to a three-dimensional percolation grid model. The porosity and permeability of the sealing interface are calculated based on the theory of porous medium, and then the leak model of the sealing interface is proposed. Furthermore, a test rig for measuring the leakage rate of metal static seal is set up, the leakage model is proved to be reasonable and correct by sealing experiment. The influences of the direction of the surface texture, the fluctuation frequency of the rough surface and the sealing material on the leak rate are studied. The numerical simulation shows that the sealing interface consisted of anisotropic surfaces has best sealing performance; the fluctuation frequency of the surface is positively correlated with the sealing performance; materials with low hardness are easy to achieve effective sealing; in the case of a high contact load, the effect of surface topography on the leak rate is negligible.