进口预旋下三种典型迷宫密封转子动力特性研究  

Study on Rotordynamic Characteristics for Three Labyrinth Seals with Inlet Preswirl

作　　者：向松莹 刘理均 王偲臣[2] XIANG Songying;LIU Lijun;WANG Sichen(Research Center of Fluid Machinery Engineering and Technology,Jiangsu University,Zhenjiang Jiangsu 212013,China;Institute of Engineering Thermophysics,Chinese Academy of Sciences,Beijing 100191,China)

机构地区：[1]江苏大学流体机械工程技术研究中心,江苏镇江212013 [2]中国科学院工程热物理研究所,北京100191

出　　处：《润滑与密封》2024年第6期185-194,共10页Lubrication Engineering

摘　　要：为探讨考虑进口预旋的迷宫密封转子动力特性,基于Murphy小位移涡动理论建立气流激振力与转子涡动位移的控制方程,采用用户自定义函数建立多频椭圆涡动模型,利用FLUENT动网格技术数值求解直通齿式迷宫密封(SLS)、倾斜齿式迷宫密封(ILS)和阶梯式迷宫密封(STLS)在不同预旋比下的激振力,通过快速傅里叶变换得到整机运行时的密封动力特性系数,并对转子稳定性和密封的泄漏量进行分析。结果表明:在40~180 Hz涡动频率范围内3种密封结构的直接刚度系数呈先减小后增大的趋势,表现出很强的频率相关性,而密封结构与进口预旋对阻尼系数的影响可以忽略;阻尼系数随涡动频率增加缓慢减小至负值并趋于平稳,其中STLS的阻尼系数最小,稳定性最差,ILS的稳定性最好;增加进口预旋比会降低有效阻尼系数,并导致泄漏量降低;STLS在不同预旋条件下的密封性能均最佳,相比于SLS与ILS的泄漏量分别减少了15%和7%;在研究的20~200 Hz涡动频率范围内3种类型迷宫密封的交叉刚度由负值增大为正值,而有效阻尼减小为负值,此时迷宫密封转子系统稳定较差,可能会诱发转子失稳。To explore the dynamic characteristics of the rotors of labyrinth seal considering inlet preswirl,based on Murphy's small displacement principle,the governing equations of steam flow excitation force and rotor vortex displacement were established,and a multi-frequency elliptical vortex model was built by user-defined functions.The exciting forces of three labyrinth seals,straight tooth labyrinth seal(SLS),inclined tooth labyrinth seal(ILS),stepped tooth labyrinth seal(STLS) were numerically solved under different inlet preswirl ratio,the seal dynamic characteristic coefficient was obtained by fast Fourier transform,and the stability of the rotor and the leakage of the seals were analyzed.The results show that the direct stiffness coefficients of the three labyrinth seals decrease first and then increase in the range of eddy frequency from 40 Hz to 180 Hz,showing a strong frequency correlation.While the influence of sealing structure and inlet preswirl on damping coefficient can be ignored.The damping coefficient slowly decreases to a negative value and then becomes stable with the increase of vortex frequency.STLS has the smallest damping coefficient and the worst stability,while ILS has the best stability.Increasing the inlet preswirl ratio will reduce the effective damping coefficient and lead to a decrease in leakage rate.STLS exhibits the best sealing performance under different preswirl conditions,with a 15% and 7% reduction in leakage compared to SLS and ILS,respectively.The cross stiffness of the three labyrinth seals increases from negative to positive in the studied vortex frequency range of 20 Hz to 200 Hz,while the effective damping decreases to negative.Therefore,the stability of the rotor system of the labyrinth seals is poor,which may induce rotor instability.

关 键 词：进口预旋 迷宫密封 气流激振 动力特性 有效阻尼 

分 类 号：TK474[动力工程及工程热物理—动力机械及工程] TH136[机械工程—机械制造及自动化]