基于CFD的端面空化对液膜密封稳态特性影响研究∗

摘要

Based on the cavitation model meeting mass⁃conserving,a three⁃dimensional model of spiral groove liquid film seal was established by CFD FLUENT software. The effects of spiral groove structure parameters on the occurrence of cavitation were discussed,and the effects of cavitation on the opening force,the stiffness of liquid,pumping flow rate and so on were analyzed.The results indicate that,by the gas⁃phase volume fraction changes in the liquid film as the criterion,the cavitation effect is increased as the groove depth and number increase,and is increased first and then decreased as the groove diameter width diameter ratio increases,but becomes weaken as the spiral angle increases.Compared with those calculated under no consideration of cavitation effect,the values of liquid film opening force and pumping flow rate are ever reduced but the variation tendencies almost remain uniform, while the liquid film stiffness fluctuates greater within a certain range of spiral groove structure parameters and affects the liquid film stability,so cavitation easily leads the instability of seals.%基于满足质量守恒的空化模型，利用CFD FLUNET软件建立螺旋槽液膜密封端面三维模型，探讨螺旋槽结构参数对密封端面空化产生的影响规律，分析端面空化对密封端面间流体膜的开启力、液膜刚度、泵送率等的影响。结果表明：以液膜中气相体积分数变化为判据，空化效应随槽深和槽数的增加而增强，随槽径宽径比的增加呈现先增强后减弱的趋势，但随螺旋角的增加而减弱；考虑空化效应后，液膜开启力和泵送量的数值与未考虑时有所降低，但变化趋势基本一致，而液膜刚度在一定的螺旋槽结构参数范围内波动较大，影响液膜的稳定性。因此，端面空化易导致密封失效。