Abstract:

Because of the significant influence of hydrostatic effect on the sealing performance of a regulatable gas lubricated seal (R-GLS), optimization of hydrostatic structural parameters of this type of seal was conducted. Based on the gas lubricated theory, Reynolds equation of the gas film between sealing rings was solved by using the finite element method (FEM). The pressure distribution of the gas film was obtained. The sealing performance, including balance gas film thickness, gas film stiffness, leakage rate and frictional loss of the seal were studied by varying hydrostatic structural parameters of R-GLS at different rotating speeds. The hydrostatic structural parameters were optimized. Analysis of sealing performance of hydrostatic gas lubricated seal (H-GLS), pumping-out gas lubricated seal (Po-GLS) and pumping-in gas lubricated seal (Pi-GLS) was made under the same operating conditions. Optimal working performance, including sealing ability, gas film stability and frictional loss could be achieved for a R-GLS when diameter of restrictive orifice was between 0.05 mm and 0.2 mm, dimensionless pressure equalizing groove depth was between 0.005 and 0.015 and dimensionless pressure equalizing groove width was between 0.02 and 0.05. Great working clearance and sealing ability could be achieved when dimensionless radius position of orifice was between 0.3 and 0.6, while excellent gas film stability could be achieved when dimensionless radius position of orifice was between 0.1 and 0.3 or between 0.55 and 0.7. Compared to H-GLS and Pi-GLS, Po-GLS was good with excellent axis gas film stiffness and balance gas film thickness, especially low leakage rate. Pi-GLS could realize zero outward leakage-rate of the regulative gas with rational design.

Key words: gas lubricated seal, sealing performance, hydrostatic structural, parameter optimization, steady state, numerical simulation, laminar flow

摘要：

鉴于可调控型气膜润滑密封(R-GLS)静压效应对密封性能的重要影响,开展该种密封端面静压结构的研究。基于气体润滑理论,采用有限元法求解了R-GLS端面间气膜的雷诺方程,研究了不同转速条件下静压结构对平衡膜厚、气膜刚度、泄漏率和摩擦功耗等密封性能的影响规律,并开展了该种密封静压结构的优化分析。对比了相同工况下静压式、泵出式和泵入式3种R-GLS的密封性能。结果表明:当节流孔直径0.05 mm< d <0.2 mm,量纲1均压槽深度0.005< H <0.015,量纲1均压槽宽度0.02< W <0.05时,R-GLS能获得较佳的密封性、气膜稳定性和较低的摩擦损耗;当量纲1节流孔位置0.3< R <0.6时能获得较大的工作间隙和较优的密封性,0.1< R <0.3或0.55< R <0.7时能获得较好的气膜稳定性;泵出式密封能在保持较大平衡膜厚、优秀气膜刚度的同时兼具较低的泄漏率;泵入式密封可以实现调控气向外零泄漏。

关键词: 气膜润滑密封, 密封性能, 静压结构, 参数优化, 稳态, 数值模拟, 层流