液体火箭发动机雷列槽结构参数对密封动态稳定性的影响

Effects of Structural Parameters of Rayleigh Groove of Liquid Rocket Engine on Seal Dynamic Stability

液体火箭发动机雷列槽密封动态稳定性受结构参数的综合影响。建立雷列槽液体润滑机械密封三自由度微扰模型,采用有限元法和小扰动法求解稳、动态雷诺方程,分析结构参数对动态特性系数和密封稳定性的影响。结果表明:同一雷列槽结构参数的变化对动态特性系数的影响程度不同;槽数、浅槽槽宽增加,浅槽内径减小时,轴向刚度系数和角向刚度系数变大,角向耦合刚度系数和动态阻尼系数变小;深槽槽宽、浅槽槽深增加,动态特性系数减小;深槽槽深的变化对动态特性系数影响较小;雷列槽密封不会发生轴向失稳,角向存在“半频摆动”现象;槽数、浅槽槽宽减小,浅槽槽深增加时,雷列槽密封容易发生角向失稳。

The dynamic stability of Rayleigh groove seal of liquid rocket engine is affected by structural parameters.A three degree of freedom perturbation model of Rayleigh groove liquid lubricated mechanical seal was established.The steady and dynamic Reynolds equations were solved by finite element method and small perturbation method.The effects of structural parameters on dynamic characteristic coefficients and seal stability were analyzed.Results show that the change of the same structural parameter of Rayleigh groove has different effects on dynamic characteristic coefficients.With the increase of groove number and shallow groove width and the decrease of inner radius of shallow groove,the axial stiffness coefficient and angular stiffness coefficient become larger,while the angular coupling stiffness coefficient and dynamic damping coefficients get smaller.The dynamic characteristic coefficients decrease with the increase of deep groove width and shallow groove depth.The change of deep groove depth has little effect on dynamic characteristic coefficients.The Rayleigh groove seal does not suffer axial instability,and the phenomenon of“half frequency oscillation”exists in angular direction.The decrease of groove number and shallow groove width and the increase of shallow groove depth are easy to cause angular instability of Rayleigh groove seal.