重型燃气轮机轴系切向支撑组合轴承的热弹性流体主动润滑研究

This project has the aim to investigate the thermoelastohydrodynamic active lubrication both theoretically and experimentally in the fixed-tilting pad combination bearing, which is with tangential links support and usually required to run at high load, low friction and high stability inside heavy duty gas turbines. A self-adaptive multi-objective optimization method will be proposed to implement 3D optimization of the textured structure of the combination bearing, and consequently the optimal design parameters of the surface terxturing will be obtained. Therefore, the design criteria of the combination bearing will be put forward while considering the system efficiency and stability, etc. The friction between spherical pivot of tilting-pad and inner surface of bearing housing will be modeled, and consequently the compliance of the spherical pivot will be taken into consideration in thermoelastohydrodynamic active lubrication of the combination bearing. A high order self-adaptive discontinuous Galerkin finite element approach will be proposed to provide insights into the mechanism of thermoelastohydrodynamic lubrication. Multi-body dynamics of tangential links for the combination bearing will be investigated, and consequently the dynamic coupling of thermoelastohydrodynamic lubrication and tangential links for the combination bearing will be established. Control strategy for thermoelastohydrodynamic active lubrication that is driven by piezoelectric actuator will be proposed, and therefore hybrid control law for thermoelastohydrodynamic active lubrication of the optimal textured combination bearing will be presented based on the observed state information. Experiments will be conducted to validate the hybrid contorl strategy and the theoretical model of thermoelastohydrodynamic active lubrication of the optimal textured combination bearing. The present research will be of value not only to the fundamental theory and but also to the key issues to the design of the fixed-tilting pad combination bearings with tangential links support in heavy duty gas turbines.

本项目围绕重型燃气轮机轴系切向支撑固定瓦-可倾瓦组合轴承，针对其承载力高、摩擦小和高稳定性的要求，进行热弹性流体主动润滑理论及实验研究。针对组合轴承，提出三维织构优化的自适应变步长多目标优化方法，得到组合轴承最优的织构设计参数；在综合考虑系统功耗、稳定性等因素的基础上，提出组合轴承的优化设计准则；通过建立可倾瓦球形支点和轴承座内表面之间的摩擦力描述模型以计入支点的顺应性，提出进行热弹性流体动力润滑分析的高阶间断自适应Galerkin有限元方法；研究切向支撑机构的多体动力学模型，建立组合轴承的热弹性流体动力润滑和切向支撑机构之间的动力学耦合关系；提出压电作动器驱动的组合轴承的热弹性流体主动润滑控制策略，构建基于可观测状态信息的组合轴承复合控制律，通过实验验证织构化组合轴承的热弹性流体主动润滑的动力润滑模型及复合控制策略。为重型燃气轮机轴系切向支撑组合轴承的设计提供有价值的基础理论和核心技术。

本项目围绕重型燃气轮机轴系流体动压滑动轴承（固定瓦、可倾瓦和组合轴承），针对其承载力高、摩擦小和高稳定性的要求，进行了热流体动力润滑研究。针对固定瓦和组合轴承，提出了三维织构优化的多目标自适应变步长优化方法及结合惯性权重动态调整和局部搜索策略的混合进化优化方法，得到了固定瓦和组合轴承最优的织构设计参数，建立了固定瓦和组合轴承的织构优化设计准则；基于变分约束原理，提出了空穴边界条件下流体动压轴承非线性油膜力的求解方法，建立了固定瓦-可倾瓦组合轴承的完整动力学模型，得到了完整动力学模型下组合轴承的动力特性系数；考虑固定瓦-可倾瓦组合轴承重载工况下的弹性变形及可倾瓦轴瓦和球形支点之间的摩擦力，提出了进行组合轴承热流体动力润滑分析的流固有限元耦合算法。通过构建计入支点摩擦的固定瓦-可倾瓦组合轴承的热流体动力润滑模型，研究了可倾瓦和组合轴承的热流体动力润滑性能；针对固定瓦-可倾瓦组合轴承支承的周向拉杆转子系统，将拉杆转子转盘以及拉杆与转盘之间的摩擦等效为非线性抗弯刚度，建立了拉杆转子的Lagrange动力学方程。运用油膜力数据库方法和组装技术，建立了固定瓦-可倾瓦组合轴承的非线性油膜力数据库，研究了固定瓦-可倾瓦组合轴承-拉杆转子系统的非线性动力学响应及其分岔规律；基于动压轴承-转子系统的可观测位移和速度扰动状态信息，提出了一种求解系统周期解及识别周期解稳定性的方法，通过求解Jacobi矩阵并结合Floquet理论，研究了系统周期解的稳定性及失稳分岔形式，分析了系统响应的周期、拟周期、多解共存和跳跃现象。通过求解动压轴承-转子非线性系统对外参数的偏导矩阵，基于系统可观测稳态和瞬态信息，实现了随控制参数变化的系统周期解及其稳定性的顺序追踪和识别。根据转子刚度修正方法建立了组合拉杆转子的动力学模型，搭建了转子模化实验台，测试了预紧饱和状态下转子从启动到跨越一阶临界转速的非线性动力学响应。