动环补偿型液膜密封三自由度动力学响应特性分析

密封环角偏差及转轴轴向振动直接影响液膜密封的动态追随性,以工程中常见的动环补偿型螺旋槽液膜密封为例,分析补偿环的动力学响应特性。建立液膜密封三自由度动力学分析模型,采用有限差分法离散计入挤压效应项雷诺方程,与膜厚方程、轴向及角向动力学方程组联立,求解补偿环中心位移及X向、Y向角偏差的响应特性。结果表明:轴向激励造成补偿环发生轴向正弦波动,但波动幅度仅为激励振幅的3. 16%;轴向激励对补偿环角向响应无影响;随偏差值的增大,静环固定角偏差及动环初始角偏差对补偿环轴向响应的影响越发凸显;动环能够对静环保持良好的角向追随性,动环初始角偏差将造成动环自身发生角振动。

3-DOF dynamic response characteristics of rotor compensated liquid film seal

The dynamic tracking property of liquid film seal is directly influenced by angle misalignment of seal rings and axial vibration of a shaft.The commonly used spiral groove liquid film seal with a flexibly mounted rotor was selected as an object to analyze the dynamic response characteristics of the compensated ring.A 3-DOF dynamic analysis model for the liquid film seal was built.Reynolds equation with a squeeze effect term discretized numerically using the finite difference method combined with a film thickness equation and dynamic equations in axial and angular directions were solved simultaneously to calculate the response features of the compensated ring's central displacement and angle misalignments.The results showed that the excitation in axial direction makes the compensated ring have a sine oscillation,but the oscillation amplitude fluctuation is only 3.16%of the excitation amplitude;the axial excitation has no effect on the compensated ring's responses in angular directions;with increase in offsets,the effects of stator fixed angle misalignment and rotor initial angle misalignment become more obvious;the rotor can maintain a good angular tracking property to the stator,and the rotor initial angle misalignment can cause itself to have angular vibration.