衍生螺旋槽对超临界二氧化碳干气密封微气膜稳态特性影响

以衍生螺旋槽为研究对象,建立衍生螺旋槽端面微气膜三维流动模型,通过软件REFPROP获取CO2在不同压力温度下的物性参数,并导入Fluent计算得到了衍生螺旋槽和经典螺旋槽的膜压分布。对比分析衍生螺旋槽和经典螺旋槽S-CO2干气密封开启力、泄漏率和气膜刚度,讨论不同入口压力和转速下湍流效应、实际气体效应以及离心惯性力对密封稳态性能的影响,揭示多种效应交互耦合对S-CO2干气密封气膜动态特性的密封机制。结果表明：衍生螺旋槽的气膜开启力、泄漏率和气膜刚度等性能参数优于经典螺旋槽,这是衍生螺旋槽两级台阶作用的结果;随着转速的增加,在湍流效应和离心惯性力的交互耦合作用下,开启力、泄漏率及气膜刚度先增大后减小,随入口压力的增大,气膜开启力、泄漏率和气膜刚度均呈近似线性增大,且压力越大衍生螺旋槽和经典螺旋槽的差异越来越明显。

Influence of Derivative Spiral Groove on Steady State Characteristics of Micro Gas Film in Supercritical Carbon Dioxide Dry Gas Seal

Taking the derived spiral groove as research object,a three-dimensional flow model of micro gas film in the end face of derived spiral groove was established.The physical parameters of CO2 under different pressure and temperature were obtained by software REFPROP,and the film pressure distribution of derived spiral groove and classic spiral groove was obtained by Fluent.The opening force,leakage rate and film stiffness of S-CO2 dry gas seal with derived spiral groove and classic spiral groove were analyzed.The influence of actual gas effect,centrifugal inertia force effect and turbulence effect on the steady-state performance of seal under different inlet pressure and speed was discussed.The sealing mechanism of interaction coupling of various effects on the dynamic characteristics of S-CO2 dry gas seal film was analyzed.The results show that the performance parameters such as opening force,leakage rate and film stiffness of the derived spiral groove are improved compared with the classical spiral groove,which is the result of the two-step action of the derived spiral groove.With the increase of rotating speed,the opening force,leakage rate and film stiffness first increase and then decrease under the mutual coupling of turbulence effect and centrifugal inertia force.With the increase of inlet pressure,the opening force,leakage rate and gas film stiffness increase approximately linearly,and the difference between derived spiral groove and classical spiral groove becomes more and more obvious with the increase of pressure.