光滑环形气体密封动态特性研究

光滑环形气体密封动态特性对透平机械转子系统稳定性有直接影响.建立三维数值分析模型,应用基于微元理论的密封动力特性系数识别方法计算光滑环形气体密封在2种出口状态(非阻塞/阻塞)、5种偏心率(ε=10％,30％,50％,70％,80％)以及3种长径比(L/D=0.5,1.0,1.5)工况下密封动态流动特性.结果 表明:在不...

Dynamic characteristics of smooth annular gas seal

Dynamic characteristics of smooth annular gas seal have a direct impact on the stability of turbomachinery rotor system.Here,a 3-D numerical analysis model was established,the identification method of seal dynamic characteristic coefficients based on micro element theory was used to calculate sealing dynamic flow characteristics of smooth annular gas seal under working conditions of 2 outlet states(non-blocking/blocking),5 eccentric ratios(ε=10%,30%,50%,70%,80%)and 3 aspect ratios(L/D=0.5,1.0,1.5).The results showed that under different outlet conditions(L/D=1.0),the seal direct stiffness coefficients decrease with increase in eccentricity and whirl frequency,and absolute values of cross stiffness coefficients and direct damping coefficients increase with increase in eccentricity;in the case of high eccentricity,effects of eccentricity on sealing characteristic coefficients must be considered,the latter can’t be simplified to the traditional 4 dynamic characteristic coefficients;under different whirl frequencies,effective damping coefficients have the opposite trend with increase in eccentricity and aspect ratio;the rotor system with low-frequency whirl,high eccentricity and larger aspect ratio is easier to lose stability.