基于弹流理论的深槽密封机制分析

Elastohydrodynamic Analysis on Mechanical Seals with Deep Groove

使用半光滑牛顿法建立深槽密封弹流模型,模型将雷诺方程、空化方程、力平衡方程及变形方程同时纳入牛顿迭代系统,使用Fischer-Burmeister函数实现对润滑液膜空化区域的识别,通过一重循环迭代寻索到空化区域并得到端面膜厚及压力场分布,算法效率显著提升。通过该弹流模型对深槽密封作用机制进行研究,并对比分析U型槽、矩形槽、圆弧槽3种型槽对密封性能的影响。结果表明:深槽密封端面周向较小的动力楔使得端面以非接触状态运行;核主泵三级密封的密封特性接近,圆弧槽在仅考虑压力变形条件下动压效应微弱,且稳定运行时其最小膜厚远小于U型槽及矩形槽。

A semi-smooth Newton iterative algorithm was presented to analyze the deep groove mechanical seal with elastohydrodynamic( EHD) theory. The iteration system included Reynolds equation,cavitation equation,force balancing equation and deformation equation. With the cavitation area of lubricant film distinguished by Fischer-Burmeister function,the EHD solution of the mechanical seal was solved by only one Newton iteration loop to find the cavitation area and to acquire the film thickness of end face and distribution of pressure. This algorithm is proved to be high efficient. The mechanism of deep groove mechanical seal was researched by this EHD model,and the impact of three different groove shapes as U,rectangle and arc grooves on the seal property was analyzed. The results show that a tiny circumferential dynamic wedge on the seal face helps the deep groove mechanical seal working in a non-contacting condition. The three stages of the nuclear pump mechanical seal show similar sealing property. The circular groove shows weak dynamic effect if considering mechanical deformation alone. The minimum film thickness of the circular groove is far less than that of U and rectangle grooves while running stably.