波箔组合式径向空气轴承结构参数对转子动力学性能的影响

Influence of Structural Parameters of Combined Bump Foil Radial Air Bearings on Rotor Dynamic Performance

摘要

本文以波箔组合式空气轴承支承的转子系统为研究对象，开展动力学性能研究：通过同时求解雷诺方程和箔片结构的变形方程，建立气体箔片轴承的流固耦合模型；采用摄动法，求解动态雷诺方程，计算箔片轴承动态性能系数；对轴承-转子系统建立参数集总化模型，采用 Riccati 传递矩阵法研究动力学特性；通过锤击试验与模型计算的前 6 阶模态频率对比，验证了模型的准确性。在此基础上，结合具体算例，数值研究了轴承半径间隙、平箔厚度、波箔厚度、波拱半长等轴承结构参数对临界转速、不平衡响应等转子动力学性能的影响规律，结果表明，在一定范围内增大半径间隙和减小平箔厚度，均能提高系统稳定性；选取合适的波箔厚度和波拱半长，能使不平衡响应振幅趋近极小值，提高系统稳定性。

Abstract

Taking the rotor system supported by the combined bump foil air bearings proposed previously by the authors as the research object, this paper carries out an investigation on its dynamic performance. A fluid–structure interaction model for the combined bump foil air bearings is established by simultaneously solving the Reynolds equation and the deformation equation of the foil structure. The perturbation method is adopted to solve the dynamic Reynolds equation and compute the dynamic performance coefficients of the foil bearings. A lumped-parameter model for the bearing–rotor system is established, and the Riccati transfer matrix method is applied to analyze its dynamic characteristics. The accuracy of the model is verified by comparing the first six modal frequencies obtained from hammer impact tests with those from model calculations. On this basis, numerical calculations are performed to explore the effects of bearing structural parameters—such as radial clearance, top foil thickness, bump foil thickness, and half-length of bump arches—on rotor-dynamic performance, including critical speed and unbalance response. Within a certain range, increasing radial clearance and decreasing top foil thickness helps improve system stability. By contrast, reasonable selection of bump foil thickness and half-length of bump arches can reduce the amplitude of unbalance response and further promote system stability. This study can offer theoretical guidance for the structural design of combined bump foil air bearings and matching rotors.

关键词

波箔组合式空气轴承 / 轴承结构参数 / 转子动力学 / 数值计算 / 不平衡响应

Key words

combined bump foil air bearing / bearing structural parameter / rotor dynamics / numerical computation / unbalance response

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