干气密封系统角向摆动改变了动静密封环间的微尺度间隙，进而影响了干气密封的密封性能，建立了角向振动下气膜-密封环系统的动力学模型，应用微扰法和龙格-库塔法求解气膜角向刚度、临界转动惯量和角向摆动的二维振动方程，获得了密封系统稳定时的密封结构参数范围，并分析了最佳稳定点和临界点振动响应。研究结果表明:在特例中螺旋角α=75°邻域内，存在着稳定区域α=74°30′06″-75°16′10″，其最佳值为αopt=74°53′48″。最佳稳定点振动响应为准周期运动，而临界点振动响应发生了混沌运动。

The angular wobbly of dry gas seal system has changed the micro-scale gap of moving and static rings and influenced the sealing performance, The dynamic model of the angular wobbly of the gas film and seal ring was established, and the gas film angular rigidity, critical moment of inertia and the two-dimensional angular wobbly vibration equation were solved by using the perturbation method and the Runge-Kutta method, then the seal structure stability parameters were obtained , and the vibratory response of best stability point and critical point were analyzed. The research results show that there are stability point-fields α=74°30′06″-75°16′10″ in the neighborhood of spiral angle α=75°,and the optimal value of the spiral angle α is 74°53′48″ in this example. The vibratory response of best stability point is quasi-periodic motion，but response of critical point is chaotic motion.