动静压混合式气体密封的特性分析

基于气体动压式和静压式密封原理,提出了新型的动静压混合式气体密封(简称混合式密封),介绍了该密封的工作原理.采用有限元法,利用Matlab数值软件,求解了混合式密封及动压式密封和静压式密封端面间气膜的Reynolds方程,得到气膜的压力分布,进而求得了密封的性能参数,如开启力、稳态刚度、泄漏率、摩擦功耗等.比较了不同端面结构的混合式密封与静压式和动压式密封的密封性能,并分析了混合式密封及静压式密封在失去气源情况下的密封性能.结果表明:与动压式密封相比,在同一气膜厚度下混合式密封获得的开启力更大,气膜厚度增加时仍具有较大的刚度;混合式密封可实现静压开启,动压运转;由于同时具有动压效应和静压效应,混合式密封工程应用范围更广;此外,混合式密封的特性参数可以通过在线调节阻封气压来改变.

Performance Study of Dynamic-hydrostatic Hybrid Gas Seal

Based on the principles of dynamic gas seal and hydrostatic gas seal, a new kind of gas seal, namely dynamic-hydrostatic hybrid gas seal(DHHGS), was proposed. Gas film pressure distribution between the two faces of dynamic seal, hydrostatic seal and DHHGS were obtained by solving the Reynolds equation of the gas film numerically. The sealing performance parameters, i.e. opening force, steady-state stiffness, leakage rate and frictional power were evaluated. Operating characteristics of DHHGS were investigated by comparing the sealing performances of different structure of seal end faces of DHHGS, hydrostatic seal and dynamic seal. Specifically sealing performances of DHHGS and hydrostatic seal without initial gas pressure were analyzed. Results showed that the opening force of DHHGS was larger in the same gas film thickness and the stiffness of DHHGS was still greater when the gas film thickness increased, compared with dynamic seal. Static opening and dynamic running could be well achieved with DHHGS. As it has both the hydrodynamic effect and hydrostatic effect simultaneously, DHHGS could find more applications in engineering. In addition the sealing performance, parameters of DHHGS could be changed through gas source pressure adjustment online.