基于箔片非线性刚度模型的气体箔片轴承静特性研究*

基于箔片轴承结构刚度试验结果推导单个波纹箔片非线性刚度模型，通过有限差分法耦合求解气体Reynolds方程、气膜厚度方程和单个波纹箔片非线性刚度方程得到了轴承静态特性，研究波纹箔片非线性刚度对轴承静态特性的影响。通过对波纹箔片非线性模型和文献中的波纹箔片等刚度模型仿真结果进行对比分析，结果表明：单个波纹箔片刚度具有很强的非线性，轴承气膜压力分布不均使得轴承承载区波纹箔片的刚度要远远大于非承载区的刚度，并且轴承轻载时非线性刚度模型刚度值较小导致仿真得到的轴颈偏心率和非承载区的气膜厚度都明显大于文献恒定刚度模型的结果。此外，通过分析得出了一种先进行刚度试验得到单个箔片非线性刚度模型后利用数值方法进行求解的箔片轴承静特性分析方法。

Static Performance of Gas Foil Bearings with Nonlinear Foil Stiffness Model

The nonlinear stiffness model of single bump foil is derived from foil bearing structural stiffness tests. By using finite difference method, the gas Reynolds equation is solved coupled with film thickness and single bump foil stiffness equation. The effects of bump foil nonlinear stiffness on foil bearing static performance are studied. The numerical results of bump foil nonlinear stiffness model are compared with constant stiffness model from reference. The results indicate that single bump foil has strong nonlinear stiffness. The stiffness of bump foil at bearing load zone is much larger than that in non-load zone due to the uneven gas pressure distribution. Since the small bump foil stiffness value of nonlinear stiffness model in light load case, the journal eccentricity and gas film thickness at non-load zone of nonlinear stiffness model are much larger that the results of constant stiffness model. In addition, a new approach to analyze foil bearing static performance is summarized which is derive single bump foil nonlinear stiffness model from bearing structural stiffness experiments before numerical analysis of bearing.