油气两相动压密封端面结构多参数正交优化及试验研究

Multi-parameter optimization and orthogonal experimental study of a two-phase oil and gas dynamic pressure seal structure

针对油滴均匀分布在气相中的油气两相动压密封,利用Fluent软件建立两相动压密封端面间流体模型,并采用多参数正交优化法,分析密封性能参数(工作膜厚、流体膜刚度、泄漏量及摩擦扭矩)随两相密封动压槽结构参数(螺旋角、槽深、槽宽比、槽坝比和槽数)的变化。分析结果表明:在恒定转速、压差和闭合力条件下,通过调整各结构参数均可获得最大工作膜厚;流体膜刚度随着螺旋角和槽深的增大而减小;气体泄漏率和液体泄漏率随密封槽结构参数变化规律相同,且变化规律与工作膜厚相同;得到了定工况下的最优动压槽结构参数。最后通过自主设计的气液两相动压密封实验装置进行静压试验和运转试验,验证了动压密封在油气两相介质工况下应用的可行性。

A complete and accurate two-phase hydrodynamic fluid film seal finite element model for a two-phase oil and gas dynamic pressure seal,in which oil droplets are evenly distributed in the gas,has been established by Fluent. The changes in sealing performance parameters（including film thickness of work,film stiffness,leakage,and friction torque） as a function of the dynamic pressure groove structure parameters（including spiral angle,groove depth,groove-width ratio,groove-bar ratio,and groove number） of the two-phase seal were analyzed using the orthogonal multi-parameter optimization method. The results show that the maximum film thickness of work can be obtained by adjusting the spiral angle,groove depth,groove-bar ratio or groove number under conditions of constant speed,pressure and closing force. Increasing the spiral angle and groove depth results in decreasing film thickness.The change in the leakage of gas as a function of groove structure parameters is the same as that for the liquid,and the behavior of the two phases as a function of varying film thickness of work is similar. The optimal dynamic pressure groove structure parameters were obtained under given conditions. The feasibility of employing the dynamic pressure seal in oil and gas two-phase medium conditions was verified by means of a self-designed dynamic pressure seal experimental device,for which static-pressure tests and running tests were carried out. A theoretical basis for the fabrication of a two-phase oil and gas dynamic pressure seal was obtained by means of this study.