流固耦合参数慢变转子系统故障的若干关键问题研究

The rotor system with slowly varying parameters applied widely in mechanical equipments, such as generators, motors, et al. It recently increases the feasibility of fault occurrence along with the developing of the design of rotor system in maximization, high-speed orientation and flexibility. So, it has an important scientific meaning and practical value for studying the nonlinear characteristics and fault mechanism of rotor system with slowly varying parameters (The rotor system with slowly varying parameters in fluid-solid coupling forces) such as large steam turbine and large scale compressor, appling hydrodynamics, nonlinear vibration, rotor dynamics and nonlinear finite element method. It can improve the reliability and stability of rotating machinery. The subject will develop theoretical and experimental investigations of fault rotor system with slowly varying parameters in double-fluid forces taking the large steam turbine as background. The research includes modeling of rotor system with slowly varying parameters in fluid-solid coupling forces, nonlinear characteristics and instability mechanism of the ultra-supercritical rotor system, sensitivity and influence law of multi-slowly varying parameters, the occurrence mechanism and fault degree of coupling faults, the stability law of motion. The fault characteristics in unsteady state will be extracted applying the signal processing method of time-frequency analysis, the influences of various factors and action mechanism will be studied. The influence and evolvement law between fluid excitation, slowly varying parameters and faults will be analyzed comparing the theoretical results. The research results of this subject will provide theoretical and technical basis for the theoretical study of rotor system with slowly varying parameters in fluid-solid coupling forces to practical application.

近年来随着转子系统的设计朝着大型、高速及柔性化的趋势发展，引发转子系统发生故障的可能性增加。因此研究密封力和油膜力等流体激励下大型汽轮机、压缩机等含参数慢变转子系统（流固耦合参数慢变转子系统）的非线性特性和故障机理，提高旋转机械的可靠性与稳定性，具有十分重要的科学意义和实用价值。本课题将以大型汽轮机组等转子系统为背景，开展多流体激励联合作用下参数慢变转子系统及其故障的理论与试验研究，包括考虑双流体激励的参数慢变转子系统非线性流固耦合建模、超超临界运行时的非线性特性和失稳机理、对多慢变参数的敏感性和相互影响规律、单一和耦合故障的发生机理和故障程度及运动稳定性；应用时频分析等信号处理方法提取非稳态下的故障特征，对各种因素的影响和作用机理进行分析研究，对比理论研究结果分析流体激励、慢变参数和故障之间的影响和演变规律，为流固耦合参数慢变转子系统研究从理论走向实际应用提供必要的理论依据和技术基础。

近年来随着转子系统的设计朝着大型化、高速化及柔性化的趋势发展，旋转机械的结构设计越来越复杂，以及在某些情况下表现出的参数慢变特征，引发转子系统发生故障的可能性增加。因此针对大型机组设计和使用过程中所面临的瓶颈问题，研究流固耦合参数慢变转子系统的非线性动力学特性和故障机理，可以为旋转机械的综合设计与控制、故障诊断与预防等提供坚实的理论依据和技术保障，具有非常重要的科学意义和实用价值。.项目以大型汽轮机组转子系统为背景，开展了流固耦合参数慢变转子系统及单一和耦合故障的理论与实验研究。建立了密封力、油膜力等流体激励作用下转子系统及其单一和耦合故障的非线性流固耦合动力学模型及参数慢变转子系统流固耦合动力学模型，开发出了流固耦合参数慢变转子系统及典型单一和耦合故障进行非线性动力学特性分析的程序。研究了转子系统在不同转速、偏心量、密封结构参数在内的动力学响应特征；分析了轴承间隙、滚珠个数、接触角等对系统振动特性的影响，总结了升/降速过程中气流激振与滑动轴承油膜失稳的频谱特征变化规律的异同点，揭示了流体自激振动的振动特性。开展了存在质量慢变、刚度慢变、激励慢变和阻尼慢变的转子系统的动力学行为研究，对系统在不同转速、不同慢变参数和不同慢变位置等工况进行了仿真和试验研究，为含参数慢变转子系统动态特性分析提供了理论依据和参考。研究了转子系统单一和耦合故障对系统非线性特性的影响及系统参数的相互作用规律，总结了其故障特征。基于特征融合方法，将故障特征提取方法和故障识别算法相结合用于对转子系统典型单一和耦合故障进行诊断识别分类，有效提高了确诊率。项目的研究成果对为流固耦合参数慢变转子系统研究从理论走向实际应用提供了一定的理论依据和技术基础。