气体箔片轴承多尺度多物理场耦合建模及启停过程中摩擦学性能演化机理研究

Gas foil bearings use air as lubricating medium and use foil structure to enhance the adaptability of bearings. It has broad application prospects in high-tech fields such as national defense and military industry. However, the existence of foil structure significantly increases the difficulty of theoretical analysis and physical modeling, making theoretical research lag behind experimental research for a long time. In addition, due to low air viscosity and poor load-carrying capacity, local overheating and wear are prone to occur during start-up and shutdown, which seriously affects the reliability and service life. In view of the above background and requirements, this project proposes introducing surface texture on the rotating shaft or foil surface to explore the potential of surface texture technology in improving the start-stop performance of gas foil bearings. Firstly, considering the multi-scale characteristics of the interface, the multi-scale mixed lubrication modeling and efficient numerical solution method considering gas compressibility are studied. Then the multi-physical field effect and the non-linear coupling relationships are analyzed, and the multi-physical field coupling modeling and numerical solution method are studied. Then, based on the multi-scale and multi-physical field coupling model, the effects of texture form (“stationary texture” and “moving texture”), parameters and distribution on start-stop performance are analyzed, and the evolution mechanism of tribological properties during start-stop process is revealed. This project will enrich the theoretical analysis methods of engineering friction pairs such as gas foil bearings, and provide valuable basis for the design and development of gas foil bearings with high reliability and long life in China.

气体箔片轴承采用空气作为润滑介质，利用箔片结构增强轴承的自适应性，在国防军工等高科技领域应用前景广阔。但是箔片结构的存在显著增加了理论分析与物理建模的难度，使理论研究长期滞后于实验研究。此外，由于空气粘度低，承载能力较差，启停过程中易发生局部过热和磨损，严重影响可靠性与寿命。针对上述背景和需求，本项目提出在转轴或平箔表面引入表面织构，探索表面织构技术在改善气体箔片轴承启停性能方面的潜力。首先针对界面处多尺度特点，研究考虑气体可压缩性的多尺度混合润滑建模以及高效数值求解方法。然后分析多物理场效应以及非线性耦合关系，研究多物理场耦合建模及数值求解方法。接下来基于多尺度多物理场耦合模型，分析织构形式(“静织构”与“动织构”)、参数、分布等对启停性能的影响，揭示启停过程中摩擦学性能演化机理。本项目研究将丰富工程摩擦副的理论分析方法，为我国高可靠性、长寿命的气体箔片轴承的研发设计提供有价值的参考。

空气箔片轴承具有低摩擦、无污染、高低温适应性强等特点，在国防军工等高科技领域应用前景广阔。但是箔片结构的存在显著增加了理论分析与物理建模的难度，此外，由于空气粘度低，承载能力较差，启停过程中易发生局部过热和磨损，严重影响可靠性与寿命。本项目首先基于考虑气体可压缩性、气体稀薄效应的修正雷诺方程和精确接触模型，构建了多尺度气弹耦合混合润滑模型。然后，为解决现有箔片刚度模型较为简化，预测精度低，通用性差等问题。利用COMSOL固体力学物理场模块，考虑库伦摩擦效应，构建了精确箔片结构刚度模型。进一步地，基于COMSOL与MATLAB联合仿真，构建了多物理场仿真分析模型。为验证模型准确性，设计并搭建了空气箔片推力轴承精密实验装置，该实验装置可以完成静态刚度、静态性能、启停性能的高精度测试。在此基础上，分析了空气箔片推力轴承启动行为，以及柔度系数、载荷、加速时间和接触刚度对其启动特性的影响。此外，本项目还采用理论和实验相结合的方法对燃气轮机可倾瓦滑动轴承和油润滑螺旋槽推力轴承进行了扩展研究。针对可倾瓦滑动轴承构建了考虑湍流和多相流效应的热弹流体动力润滑模型，并利用搭建的高速可倾瓦滑动轴承试验机和新型两相流实验装置，对模型的准确性进行了验证。针对油润滑推力轴承，引入仿生螺旋槽，研究了启动过程中摩擦学性能的演化，并对螺旋槽参数进行优化分析。本项目研究丰富工程摩擦副的理论分析方法，为我国高可靠性、长寿命的气体箔片轴承、可倾瓦滑动轴承的研发设计提供有价值的参考。