Finger Seal Dynamic Hysteresis Characteristic Analysis

Finger Seal (FS) is one kind of new seal technologies developed in recent years and many researches have been done about FS;especially the hysteresis characteristic of FS has received most attention. The former domestic and foreign research about hysteresis characteristic of FS is mostly carried out based on the three-dimensional model with static loads. But the dynamic behavior of the FS system, when the rotor runs at high speed, was not considered in these models. The reason is that it's very difficult to analyze the dynamic characteristic of the FS based on the three dimensions model, and the corresponding optimization mathematical model is hard to establish either. In this condition, the optimization of FS's hysteresis characteristic can't be managed well. In view of the situation, in order to solve this problem, the paper gains the relations between working parameters, structure parameters as well as dynamic parameters of FS system through finite element analysis and data process. Furthermore, a spring - mass - damper dynamic model of the FS system is proposed, so that the dynamic hysteresis characteristic analysis of the FS based on the dynamic model can be carried on now.In order to get the equivalent stiffness and equivalent mass of FS system, orthogonal experiment design has been used and finite element simulation experiments have been done in ANSYS considering the multi- structure parameters and multi- working parameters of FS system. And equivalent friction force of the FS system was gained by using MATLAB software. In further research, a spring - quality - damper dynamic model of FS system is proposed to describe the dynamic running of FS system. This work transforms dynamic hysteresis characteristic analysis, which can't be carried out on original FS system, into the analysis of heavy damp vibration of the spring - quality- damper dynamic model. By using the new model, the difficulty is greatly simplified and calculation is decreased too. A comparison between FS system's dynamic computation and static computation based on the finite element analysis shows that the dynamic model proposed in this work is valid, and the more accurate result shows that the dynamic characteristic analysis of the FS is necessary.Dynamic model proposed in this paper can reflect the real dynamiccharacteristics of FS. Meanwhile, the optimization of the FS system based on the dynamic model can be mapped to real FS system by establishing the relation between the dynamic parameters, structure parameters as well as working parameters. And the dynamic model is the base for structure optimization design of the FS.In addition, this article conducts the elastic-plastic deformation research about FS. The research work here shows that frictional retardation is the main reason that leads up to the hysteresis of FS system, in the range of structural and working parameters.