沟槽参数对螺旋槽液膜密封空化诱发影响分析

为进一步探索液膜密封端面空穴发生诱因及其影响规律，本文基于JFO（Jakobsson-Floberg-Olsson）空化边界，建立双坝区中间开螺旋槽的液膜密封物理模型，通过空穴可视化实验验证了程序算法的准确性，分析了不同空化边界下液膜密封的空穴特征。以密封面间润滑液体的液膜压力和密度变化为判据，探讨了槽深、槽角和槽数等参数对液膜始破位置、重生位置及空穴发生面积的影响。结果表明：相比Half-Sommerfeld和Reynolds空化边界，基于JFO空化边界计算的空穴特征能更好地与实验结果相吻合；较大槽深和槽数，均缩小了液膜始破位置沿螺旋方向的空穴长度和液膜重生位置沿周向的空穴宽度，前者提升了两位置的空穴度，而后者降低了液膜重生位置的空穴度；槽角的增大，在扩大两位置空穴尺度的同时，提升了相应位置的空穴度；而液膜中空穴发生面积随槽深的增加线性降低，在较小槽角时先线性增加后随槽角增大呈抛物线增加趋势，而在槽数大于12时随槽数增加线性降低。

Analysis of effect of groove parameters on cavitation induction of spiral groove liquid film seals

In order to further explore the cavitation inducements of liquid film seals and their regular influences,based on the Jakobsson-Floberg-Olsson (JFO)cavitation boundary,physical model of liquid film seals with spiral groove in the middle and double dam areas was established. The accuracy of the programmed algorithm was verified by cavitation visualization experiment,and the cavitation characteristics of liquid film seals under different cavitation boundaries was analyzed. Effects of groove parameters such as groove depth,groove angle and groove number on the location of liquid film rupture and reformation as well as the cavitation occurrence area were probed into,with the changes of pressure and density of the lubricant between the sealing faces as the criterion. Results showed that cavitation characteristics calculated by JFO cavitation boundary can be better matched with the experiment results,compared with Half-Sommerfeld and Reynolds cavitation boundaries. Both larger groove depth and groove angle are help to shorten the cavitation length along the helical direction at the locus of liquid film rupture and the cavitation width along the circumferential direction at the locus of liquid film reformation,and the former promotes the cavitation degree of the two locations while the latter reducing that of the liquid film reformation location. Increasing groove angle enlarges the cavitation sizes of the two locations and also promotes the cavitation degrees of the corresponding locations. Cavitation area in the liquid film decreases linearly as groove depth increases and it shows a linear upward trend as groove angle is small followed by a parabolic increase trend with increasing groove angle. When groove number is more than 12,the cavitation area takes on a linear decrease trend as it increases.