干气密封气膜-密封环系统角向摆动的失稳分析

Instability Analysis of Angular Wobbly for Gas Film and Seal Ring in the System of Dry Gas Seal

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,获得了密封系统失稳时的密封结构参数,分析了临界转动惯量与螺旋角之间的定量关系及失稳点振动的非线性动力学行为,并对模拟结果进行了试验验证.研究结果表明:在静态优化出的螺旋角范围(60°～80°)内,存在着失稳点域,特例中发现有16处,并且在变工况(不同的介质压力、转速)下,虽其振幅发生了变化,但其失稳点的螺旋角数值不变,这与试验结果相吻合.

The dynamic model of the angular wobbly of the gas film and seal rings was established, and the gas film angular rigidity, critical moment of inertia and the angular wobbly two-dimensional vibration equations was solved by using the perturbation method and the Runge-Kutta method, then the seal structure instability parameters were obtained, quantitative relation of critical moment of inertia and the angle and the nonlinear dynamic behavior of the vibration was analyzed. The simulation resuhs was verified by testing. The results show that there are instability point-fields in the spiral angle range （usually 60° - 80°） of the static optimization, and 16 points in the special case are found and the amplitude will be changed but the spiral angle on the instability point-fields will not be changed under the variable conditions （medium pressure and speed is changed）, and the results coincide well with experimental results.