蜂窝密封动力特性计算方法的改进及应用

Improvement and application of control-volume model on honeycomb seal

针对蜂窝密封的转子动力学特性分析,本文由双控制体模型入手,建立相应的控制方程,将其无量纲化,并通过摄动分析分解为零阶及一阶无量纲方程。通过零阶方程求得定常流场,确定流场是否发生阻塞现象,继而求解一阶方程得到密封的动力特性系数。本文的双控制体模型在蜂窝密封静子和转子表面采用Blasius模型的摩擦系数,且舍弃转子轴心传统的圆轨迹小扰动假设,直接设定为椭圆轨迹小扰动,加之矩阵形式的表达,得到了更为清晰的模型及更为简洁的算法。随后与实验结果相比较,验证模型及计算结果的准确性,并比较一般气体密封的计算结果,体现蜂窝密封在稳定性方面的优越性。最后分析了几种密封参数对其动力特性的影响,揭示某些规律并给出一些建议。

As for the analysis of honeycomb seal rotordynamics,the two-control-volume model is an efficient approach that is applied well.This paper starts with six relative governing equations,which are resolved into three dimensionless equations after a nondimensionalized process.It contains a zeroth-order equation,through which a steady fluid distribution is determined and a judgment is made whether the choked flow exists,and a first-order equation,through which the seal＇s rotordynamic coefficients can be acquired.In this paper,Blasius frication model is used for the surface of both stator and rotor due to its briefness and effectiveness.Furthermore the original assumption that the shaft moves in an orbicular track is discarded and this paper assume that the shaft moves in an elliptical track.And since the model is formulated with matrix form,the relevant operation becomes very simple so that the approach in this paper has a clearer model and a more concise algorithm than the previous ones.At last a comparison between the theoretical and experimental results are made to demonstrate the effectiveness of the model and the algorithm as well as a contrast between honeycomb seal and general annular gas seal to explain the advantage of honeycomb seal in stability.Also a series of investigations about the influence of some seal parameters reveal some helpful and practical rules.