基于渗流原理的液体润滑机械密封的泄漏率研究

Study on Leakage Rate of Liquid Lubricatedmechanical Seal Based on Percolation Theory

针对现有机械密封端面泄漏通道模型存在的不足,考虑到流体在端面间的流动过程和渗流过程具有相似特征,建立了基于渗流原理的接触式机械密封端面间渗流通道模型,利用达西公式计算了端面间的泄漏率。研究了表面粗糙度、膜厚对孔隙率的影响,表面粗糙度对最大微凸体直径的影响,以及膜厚、表面粗糙度、端面宽度和对泄漏率影响。结果表明,孔隙率随表面粗糙度的增大而减小,随膜厚的增大而增大;最大微凸体直径随表面粗糙度的增大呈线性增大趋势;泄漏率随表面粗糙度的增大先增大后减小,随膜厚的增大而增大,随密封端面宽度的增大而减小。提出的研究方法为更准确计算接触式机械密封的泄漏率提供了新思路,对进一步探究密封的泄漏机理具有一定的科学意义。

As to the drawback of available leakage channelmodel inmechanical seal face,considering the similarity of fluid flow throughmechanical seal end face and porousmedia,percolation channelmodel of contactingmechanical seal end face is established based on the percolation theory.The leakage rate is estimated by the Darcy equation.The effect of roughness and film thickness on porosity,the effect of roughness onmaximum asperity radius,and the effect of roughness,film thickness,end face width on the leakage rate are analyzed respectively.The results show that porosity decreases with the increase of roughness,while increases with the increase of film thickness;maximum asperity radius increases linearly with the increase of roughness;the leakage rate initially increases with the increase of roughness then decreases with it,the leakage rate increases with the increase of film thickness,while decreases with the increase of end face length.The research proposed a newmethod to accurately compute the leakage rate of the contactingmechanical seal.It ismeaningful to further study of the leakingmechanism ofmechanical face seal.