单双列螺旋槽干气密封端面气膜刚度比较

Comparison of the Gas Film Stiffness between the Spiral Groove Dry Gas with Single-row Grooves and Double-row Grooves

双列螺旋槽干气密封通常被认为具有比单列螺旋槽干气密封更高的气膜刚度,因而更有利于干气密封的稳定运行,但是尚未见具体的理论分析或实验数据来验证这一结论。针对某一双列螺旋槽干气密封,采用窄槽理论,利用Mathcad软件计算得到端面气膜压力分布和开启力,并得到开启力与膜厚的拟合曲线,以及气膜刚度与膜厚的函数曲线,并与单列螺旋槽进行对比。计算结果证实了双列螺旋槽干气密封具有比单列螺旋槽更高的气膜刚度,尤其是在开启力较小,气膜厚度较大的情况下,其主要原因是双列螺旋槽干气密封在同一开启力下,具有较小的平衡气膜厚度,即气膜的高刚度大部分是依靠减小的气膜厚度获得。双列螺旋槽干气密封端面开启力稍小,泄漏率稍大。

The dry gas seal with double-row spiral grooves is generally considered to have higher gas tltm Stlttness man the dry gas seal with single-row spiral grooves and is more conducive to the stable operation of dry gas seal, but there is no specific theoretical analysis or experimental data to validate this conclusion. Based on the narrow groove theory, the gas film pressure distribution and the opening force for a specific dry gas seal with double-row spiral grooves were calculated by using Mathcad software. The fitting curves of opening force and film thickness, and the function of gas film stiffness and film thickness were obtained. The calculated result was compared with that of the dry gas seal with single-row spiral grooves. The resuh shows that the dry gas seal with double-row spiral grooves has a larger gas film stiffness, especially in the case of small opening force and lager gas film thickness, and main reason is the double-row spiral groove has a smaller balance film thickness under the same opening force, which means to obtain the higher gas film stiffness is mostly relied on reducing gas film thickness. The dry gas seal with double-row spiral grooves has slightly smaller opening force and slightly larger leakage