螺旋槽干气密封系统轴向振动响应及结构优化

以密封静环为振子建立了气膜-密封环流固耦合系统轴向振动的计算模型,利用PH线性化方法、复函数分离变量法和小参数迭代法近似求解雷诺方程,求得了气膜动压近似解析式,进而求出了气膜推力.以此推力作为振动方程的激振力,建立了轴向单自由度受迫振动方程;利用龙格-库塔法求解,获得了不同螺旋角和槽深响应的振动相轨图和时间历程图,并分析了螺旋角和槽深对振动位移的影响.研究结果表明：螺旋角和槽深对振动参数均有影响,其中螺旋角对振动最为显著.改变螺旋角和槽深数值可以控制密封环的振幅,通过选择其最佳值可以保证干气密封运行的稳定性.本实例的最佳值为螺旋角74°58′48,″槽深5μm,与试验数据基本一致.

Dynamic response of axial vibration and structural optimization for dry gas seal system with spiral groove

A calculation model on the fluid-solid coupling system of gas film and seal rings subjected to axial vibration was established by taking static seal ring as the oscillator,and the Reynolds equation was approximately solved by using PH linearized method,complex function variables separation method and small parameter iterative method.The approximate analytic expression of gaseous film dynamic pressure and gaseous film force were obtained.Axial forced vibration equation of single degree of freedom was established by taking gas film force as the exciting force,which was solved by using the Runge-Kutta algorithm,then the vibration phase chart and the time history chart responded by the different spiral angles and grooved depth were obtained,and the effect of spiral angles and grooved depth on vibration displacement was analysed.The results show that vibration parameters were affected by spiral angles and grooved depth,and the vibration caused by spiral angles is the dominant one.The vibration amplitude of seal ring can be controlled by changing spiral angles and grooved depth,and the dynamic stability of gas seal can be kept by selecting their optimal value.The optimal values of the spiral angles and the groove depth in this example are 74°58′48″ and 5 μm respectively,and which are in agreement with the experimental data.