引入弹性箔片对动压轴承静动态特性影响数值研究

Numerical Study on Effects of Bump Foil on Static and Dynamic Characteristics of Aerodynamic Bearings

关键词:  弹性箔片  动压轴承  刚性表面轴承  静态特性  动态特性

Key words:  Bump foil  Aerodynamic bearing  Rigid surface bearing  Static characteristic  Dynamic characteristic

摘要:

随着高速透平机械的快速发展，应用其中的动压轴承也在不断与时俱进。但刚性表面动压轴承和弹性箔片动压轴承的轴承特性对比尚不充分，所以本文系统性地比较了两种轴承的静动态特性并总结各自的优劣及其适用环境。基于中心差分法将可压缩Reynolds方程离散化后，分别与两种动压轴承的气膜厚度方程进行耦合迭代，求解获得静态特性结果。在静态特性的基础上，应用小扰动法求解各自的动态特性参数。将这两种动压轴承的静动态特性参数进行对比研究发现，刚性表面动压轴承的承载特性要优于弹性箔片动压轴承，但影响轴承稳定性的偏位角却不如后者；且刚性表面动压轴承的动态特性参数在大偏心、高转速的工况下均要优于弹性箔片动压轴承，但由于没有弹性箔片的保护，在启停过程中磨损较为严重。

Abstract:

With the rapid development of high speed turbine machinery， the application of aerodynamic bearings has been advancing with the times. The comparison of bearing characteristics between the rigid surface aerodynamic bearings and the bump foil aerodynamic bearings is not sufficient， so the static and dynamic characteristic of the two bearings are systematically compared to summarize their advantages， disadvantages and applied environment. Based on the central difference method， the compressible Reynolds equation was discretized， which was coupled with the two different gas film thickness equations respectively to obtain the static characteristics. Based on the static characteristics of bearings， the small disturbance method was used to acquire the dynamic characteristic parameters of them. The static and dynamic characteristics of the two kinds of aerodynamic bearings were compared. It is found that the bearing capacity of rigid surface aerodynamic bearings is better than that of bump foil aerodynamic bearings， while the attitude angle affecting the bearing stability is not as good as that of the latter. The dynamic characteristic parameters of the rigid surface aerodynamic bearing are better than those of the other under the conditions of large eccentricity and high speed， but the wear is more serious in the start and stop process without the protection of the bump foil.