干气密封动静环双自由度系统的轴向振动响应

Axial Vibration Response to a Double Degree of Freedom System of the Rotating and Stationary Ring in Dry Gas Seal with Spiral Groove

基于螺旋槽干气密封动静环振动特性,在忽略阻尼作用条件下,建立了螺旋槽干气密封无阻尼气膜-密封环双自由度系统轴向振动的动力学模型和相应的数学模型,并利用待定系数法求解,获得了在谐波激励下的动静环振幅解析式。将此理论结果与试验数据比较,研究表明:动、静环轴向振动频率和振幅相同,说明动、静环追随性好,能保证气膜微尺度稳定性;在同转速下介质压力对振幅基本没有影响;动环转速越大,振幅越小,系统越稳定。试验与理论结果相符,说明了轴向振动模型的正确性,为干气密封的动态优化设计提供了理论依据。

A dynamical model and a corresponding mathematical models for the axial vibration of double degree of freedom system of undamped gas film sealing ring for spiral groove dry gas seal are constructed on the vibration property of rotating and stationary ring with the ignorance of damping effect.An amplitude analytic expression for rotating and stationary ring through harmonic excitation is acquired through using the method of undetermined coefficients.Rotating and stationary ring owns a high matching property which can guarantee the microscale stability of gas film on the condition that the frequency of rotating and stationary ring axial vibration and amplitude is same.Ambient pressure shows no impact on the amplitude at the same rotational speed.Amplitude decreases with the increase of rotational speed of rotating ring, but the system hold a higher stability under this condition.The findings correspond with test data,it explains the accuracy of the axial vibration model and provides a theoretical basis for the dynamic optimum design of the dry gas seal.