双激励耦合与悬臂式弹性支承影响的高速高比压滑动轴承系统润滑和动力学分析

The journal bearing system with high load carrying capacity and high stability is an important part of Geared Turbo Fan engine (GTF). The traditional theory model and technology system are not suitable for journal bearings used in aero-engines for the restriction of weight and size, the special structure of gear reducer, and the complex conditions of journal bearings. In order to solve the scientific problems and key techniques under the influence of two coupling excitations and cantilevered flexible support, the lubrication performance and dynamic analysis of the high-speed and high-specific-pressure journal bearing system in GTF is studied in this project. The research is carried out by theoretical analysis, numerical simulation, and experimental test. A model incorporating the coupling influence of surface texture and hybrid recesses is developed to study the hydrodynamic journal bearing. The loading mechanism of the bearing under high-speed and high-specific-pressure condition is clarified. The load sharing method based on the customized load carrying capacity is explored. And this method is used for optimizing the load distribution of GTF journal bearing system supported by the cantilevered flexible support. The nonlinear dynamic model of the GTF journal bearing system incorporating the influence of two coupling excitations and cantilevered flexible support is firstly developed, and then a dynamic analysis model is established for the journal bearing-gear-shaft system. And the influence of the interaction on the dynamic performance of journal bearing-gear-shaft system is also investigated. A technical method is developed to improve the performance of input and output in the journal bearing system. The work of this project is significant for developing new theoretical model and new technical system, expanding and improving the research areas and application fields of journal bearing and engineering tribology.

高承载高稳定性的滑动轴承系统是齿轮传动涡扇发动机（Geared Turbo Fan engine，简称GTF）减速器支承技术研究的一项重要内容，而航空发动机对重量尺寸的限制、减速器的特殊结构及支承轴承所处复杂工况使得以往滑动轴承的研究模型和技术难以满足要求。本项目以具有“转轴固定、轴瓦旋转”结构特征的GTF滑动轴承系统为对象，围绕高速高比压工况、内外啮合力双激励耦合与悬臂式弹性支承影响下产生的科学问题和关键技术，对其进行润滑和动力学分析，阐明微织构/动静压油腔多尺度混成设计模式下高速高比压滑动轴承系统的承载机理，揭示基于定制承载量的悬臂式弹性支承GTF滑动轴承系统的载荷分流机制，建立双激励耦合与悬臂式弹性支承影响的GTF滑动轴承系统非线性动力学分析模型。本项目对于发展高承载高稳定性GTF滑动轴承系统的新理论模型和新技术路径，拓展滑动轴承及工程摩擦学的研究领域和应用范畴都具有重要意义。

本研究基于 Navier-Stokes 方程，考虑空化与惯性效应耦合作用，建立了数值仿真模型，研究了单个微织构内润滑油流动特性及其与织构型滑动轴承承载力的关系，分析了表面织构、工况条件和空化与惯性耦合效应对承载力的影响。考虑轴径-油膜-轴瓦之间共轭传热的影响，建立了织构型滑动轴承的三维热流体润滑分析模型，计算了织构型滑动轴承的热流体润滑性能，研究了表面织构参数和弹性变形对织构滑动轴承热流体润滑性能的影响。研究发现，空化与惯性效应都对轴承承载力有影响；在高速大偏心工况下，在油膜收敛区域合理设置部分织构，可以提高滑动轴承的性能。然后基于有限差分法和柔度矩阵法建立了粗糙表面滑动轴承的热弹流润滑分析模型，分析了结构参数、形貌参数和工况参数对高速高比压GTF滑动轴承热弹流润滑性能的影响规律，分析了轴颈弹性变形和轴颈倾斜对GTF滑动轴承热弹流润滑性能的影响，发现表面形貌对滑动轴承的润滑性能有重要影响，弹性变形导致承载能力明显下降，油膜厚度及油膜温度分布也更不均匀。研究了具有不同轴颈型面的滑动轴承的热弹性流体润滑性能，在进行轴颈型面分析后优选出中空鼓形轴颈，得到了更适宜GTF滑动轴承工况的轴颈结构。基于遗传算法和BP神经网络技术，建立动载滑动轴承GA-BP神经网络模型，形成滑动轴承瞬时轴心位置参数和运动参数与其非线性特性之间的映射关系。在考虑轮齿间和滑动轴承间隙内油膜的润滑效应的前提下，建立了综合考虑齿面摩擦激励、轮齿时变啮合刚度和阻尼激励、滑动轴承非线性油膜力和油膜摩擦力矩的人字齿轮-转子-滑动轴承系统动力学模型，并开展了系统动力学特性的影响分析。建立了人字齿轮-转子-滑动轴承系统动力学特性试验装置，试验测量了滑动轴承油膜压力和齿轮副沿啮合线方向的相对振动，并将试验结果与理论计算结果进行了对比分析。本研究对于GTF发动机齿轮传动系统分析、滑动轴承设计及工程摩擦学应用都具有重要意义。