小孔节流动静压混合式浮动环密封承载与泄漏特性分析

Load Capacity and Leakage Analysis of Hybrid Floating Ring Seals with Throttle Orifices

关键词:  密封  小孔节流  流体膜  压力分布  承载力  泄漏量

Key words:  Seals  Throttle orifices  Liquid film  Pressure distribution  Load capacity  Leakage rate

摘要:

为了解决传统浮动环密封存在的摩擦磨损问题，提出一种采用小孔节流的动静压混合式浮动环密封（HFRS）。核心是通过创新设计将密封介质从径向节流孔引入密封界面，使密封间隙内的流体膜同时具有静压和动压承载效应，显著提升浮动环密封承载性能而不需要外部条件。为了研究其承载和泄漏特性，建立了考虑入口压力损失和节流孔影响的HFRS承载力模型和泄漏量计算方法。采用有限差分法（FDM）及数值迭代程序计算流场压力分布，并分析获得转速、偏心率和密封介质压力对承载力、刚度、偏位角和泄漏量的影响规律。与传统直孔式浮动环密封（FRS）对比，在典型工况（偏心率ε=0.5，转速Ω=2×10⁴r/min）下，HFRS的承载力是FRS的2.53倍，且在低速甚至转速为零时HFRS仍具有较大的承载力，另一方面HFRS的泄漏量比FRS大5.4%。与FRS对比结果表明，HFRS的承载力显著提升，而泄漏量略有增大。

Abstract:

In order to solve the friction and wear problems existing in traditional floating ring seal， a novel hybrid floating ring seal （HFRS） with throttle orifices was presented. Through innovative design， the sealed medium is introduced into the sealing gap from radial throttle orifices， so that the lubricant film in the sealing gap both has hydrostatic and hydrodynamic bearing effect simultaneously， which significantly improves the load capacity of HFRS without external conditions. To study the load capacity and leakage characteristics of HFRS， the mathematical model and numerical method were established and validated considering the inlet pressure loss and orifices effect. The lubricant film pressure distributions of HFRS and FRS （short for floating ring seal） were calculated with finite difference method and an iterative procedure， and the effects of rotation speed， eccentricity and upstream pressure on load capacity， stiffness， attitude angle and leakage flow rate were analyzed. According to the research results， the load capacity of HFRS is 2.53 times that of FRS under typical working conditions（eccentricity ratio ε=0.5，rotation speed Ω=2×10⁴r/min），and the load capacity of HFRS is still great even if the rotation speed is zero. On the other hand， the leakage flow rate of HFRS is slightly greater than that of FRS， which is 5.4% greater under typical working conditions. The results of comparison with FRS show that the load capacity of HFRS improves significantly， while the leakage flow rate increases slightly.