新型组合槽端面干气密封特性研究

为了进一步提升干气密封端面流体膜动压效应,提出一种新型组合槽端面干气密封,该组合槽由两个相邻的螺旋槽周向部分重叠组合而成,包括一个长螺旋槽,一个短螺旋槽,两槽的槽深及径向长度不同。建立该组合槽与传统槽端面密封的数学模型,并运用有限差分法对其密封性能进行数值分析。结果表明:新型组合槽在端面间隙约小于1.5μm区域,流体膜开启力大于传统槽,且间隙越小,两者差值越大;泄漏量亦大于传统槽,但其值远小于泄漏量的设计值;在端面间隙约小于3.5μm区域,新型组合槽流体膜刚度显著大于传统槽,且间隙越小,两者差值越大。鉴于组合槽在泄漏量不超标的情况下,在间隙较小时端面流体膜具有更大的刚度、开启力及刚漏比,其综合性能显著优于传统槽型密封。

Study on Sealing Characteristics of Dry Gas Seal with New Combination Groove End Face

In order to further enhance the dynamic pressure effect of fluid film on the end face of dry gas seal,a new dry gas seal with combined groove face was proposed.The combined groove is composed of two adjacent spiral grooves which are partially overlapped in the circumferential direction,including a long spiral groove and a short spiral groove,and the groove depth and radial length of the two grooves are different.The mathematical model of the combined groove seal was established,and the sealing characteristics were analyzed by finite difference method.The results show that when the end clearance is less than 1.5μm,the opening force of the fluid film of the combined groove seal is larger than that of the traditional groove seal,and the smaller the clearance,the greater the difference of opening force between the two seals.The leakage of the combined groove seal is larger than that of the traditional groove seal,but the leakage is much smaller than the design value.The film stiffness of the combined groove seal is significantly larger than that of the traditional groove seal when the clearance is less than 3.5μm,and the smaller the clearance,the greater the difference of film stiffness between the two seals.In view of the end face film of combined groove has greater stiffness,opening force and leakage ratio when the clearance is small under the condition that the leakage of the combined groove seal does not exceed the standard value,so the comprehensive performance of the combined groove seal is significantly superior to the conventional groove seal.