表面波度对液体椭圆孔端面密封上游泵送特性的影响

表面波度与端面几何型槽的耦合影响使得密封性能的变化规律更为复杂。基于粗糙和波度表面假设，建立空化效应下端面椭圆孔液体上游泵送密封的理论分析模型，对上游泵送端面密封的压力分布和泄漏率进行数值求解计算，分析周向表面波度幅值、数量等几何参数和转速、密封压力等操作参数对开启力和泄漏率的影响规律。结果显示：表面波度使得密封端面产生更高的流体动压效果，并减弱上游泵送效果，容易导致密封介质的泄漏；随着波高和周向波数的增加，开启力略有增加；泄漏率随着波高的增加呈现正向增强趋势，但波数对泄漏率没有明显影响；在空化效应和表面波度的影响下，速度剪切产生的密封端面开启力可增加50%以上，并形成流体的完全上游泵送；密封压力和膜厚的增加，使得流体的上游泵送性能和密封性下降。

Influence of Surface Waviness on Upstream Pumping Characteristics of Liquid Ellipse-Dimples Face Seal

The coupling effect of surface waviness and geometric groove of seal face makes the variation of sealing performance more complicated.Based on the assumptions of rough and wavy surface and considering the cavitation effect,a theoretical model of upstream pumping liquid seal with inclined-ellipse-dimples was established,and the pressure distribution and leakage rate of upstream pumping face seal were numerically calculated.The influences of geometrical parameters such as waviness amplitude and waviness number and operating parameters such as rotational speed and sealing pressure on opening force and leakage rate were analyzed.The results show that considering the surface waviness,the seal face exhibits a higher hydrodynamic effect,but the surface waviness easily leads to the leakage of the sealing medium and weakens the upstream pumping effect.With the increase of wave amplitude and waviness number,the opening force slightly increases.The leakage rate is positively enhanced with the increase of wave amplitude,but the waviness number has no obvious effect on the leakage rate.Under the influence of cavitation effect and surface waviness,the opening force of seal face generated by velocity shear can be increased by more than 50%,and complete upstream pumping of fluid is formed.The increase of seal pressure and film thickness reduces the upstream pumping performance and sealing performance of the fluid.