密封是透平机械减小泄漏的关键部件，其气流激振特性对转子系统稳定性具有重要影响。该研究基于计算流体力学与多频涡动密封动力特性系数识别方法研究逆滞流迷宫密封气流激振特性，计算分析逆滞流喷嘴结构参数及位置对迷宫密封动静特性的影响，揭示其抗气流激振机理。结果表明：逆滞流喷嘴能有效抑制周向流动，改善密封腔压力分布，提高系统稳定性；与传统迷宫密封相比，逆滞流迷宫密封具有更小交叉刚度k、更大直接阻尼C与有效阻尼Ceff，特别在低涡动频率下，效果更显著；相同结构参数逆滞流喷嘴的径向位置存在最佳值，当型心高度hc=1.65 mm(径向中心)时密封有效阻尼Ceff最大；增大喷嘴进口高度hin、减小进出口高度比例hout/hin均有利于提高系统稳定性；喷嘴进口高度hin=1.00 mm、进出口比例hout/hin=0.25、型心高度hc=1.65 mm为计算工况下最优结构，但泄漏量略有上升。

Annular seals are the key component of turbomachines to reduce the fluid leakage.The fluid-induced vibration characteristics of the annular seal are extremely crucial to the system stability.Based on the computational fluid dynamics method and a multiple frequencies whirling model, the fluid-induced vibration characteristics of an anti-stagnant labyrinth seal were investigated.The effect of anti-stagnant nozzles’geometry parameters and its position on the dynamic and static characteristics was studied.The fluid-induced vibration suppression mechanism of the anti-stagnant nozzles was examined.The results show that the anti-stagnant flow can significantly suppress the circumferential flow, and improve the pressure distribution on seal cavities and the system stability.Compared with the traditional labyrinth seal, the anti-stagnant labyrinth seal possesses a smaller cross-coupled stiffness coefficient k, a larger direct damping coefficient C and an effective damping coefficient Ceff.The suppression effect on the unstable vibration is especially remarkable at low frequencies.There exists an optimal radial position for the anti-stagnant nozzle with identical geometric parameters.When the centroid height hc is 1.65 mm, the effective damping Ceff is the largest.Increasing the nozzle inlet height hin and decreasing the ratio of outlet/inlet height hout/hin can both improve the system stability.The anti-stagnant labyrinth seal with hin=1.00 mm, hout/hin=0.25, hc=1.65 mm, is the optimal structure for the current calculation conditions, while the leakage flowrate increases slightly.