航空发动机气动-结构-油液耦合失稳振动的自抑制机理研究

The sixth generation adaptive engine which is the most advanced in the world has been conducted in rig test in the United States. The "self-suppression" of the instable vibration is also one of the key problems need to be solved in adaptive engine. The whole engine vibration showed significant characteristics of multi-physical field coupling,therefore,revealing the " mechanism of aerodynamic-structure-oil coupling vibration " and the "law of rotor stability under the multi-physical field coupling " has been a significant method to solve the problem of instable vibration self-suppression in the new generation engine..This project aims at the design requirements of new generation engine, proposed a thought of coupling instable vibration "self-suppression", which is based on the stable boundary controlled by rotation speed. This project could establish the dynamic model of aeroengine with multi-physical field coupling and deduce the mathematical equation of equivalent coupling force, which are the foundation to carry out the work of numerical simulation and experimental research. This project could research the mechanism of engine field coupling vibration, the dynamic characteristics of complex structure under the exciting of coupling fault force and the rotor instability phenomenon caused by the multi-physical field coupling effect. This project direct at reveal the generating mechanism of instable vibration with the couple of aerodynamic-structure-oil and find out the influence of main factors on the vibration characteristics. Based on these work, the stability boundary of coupling vibration could be determined and the "self-suppression" method of coupling instability vibration could be established. This project designed be a new attempt for the "self-adaptive" of structural dynamic characteristics of aeroengine.

世界最先进的第六代自适应发动机已经在美国进行了台架试车。失稳振动的“自抑制”也是自适应发动机需要解决的重点问题之一。由于发动机整机振动表现出显著的多物理场耦合特性，揭示“气动-结构-油液耦合振动机理”以及“多场耦合作用下的转子稳定性规律”成为解决新一代发动机失稳振动自抑制的关键科学问题。.本项目针对新一代发动机设计需求，提出基于稳定边界转速控制的耦合失稳振动的“自抑制”的思路。建立航空发动机多场耦合动力学模型，推导等效耦合力的数学表达式，并以此为出发点开展数值仿真和实验研究工作。探索发动机多场耦合振动机理、耦合故障力激励下的复杂结构动力学特征和多场耦合效应引发的转子失稳现象。力图揭示发动机气动-结构-油液耦合失稳振动的发生机理，探明主要因素对振动特性的影响规律，确定耦合振动的稳定边界，建立耦合失稳振动的“自抑制”方法，为航空发动机结构动力学特性“自适应”进行新的尝试。

针对发动机整机振动表现出的多物理场耦合特性，开展了为期四年的“航空发动机气动-结构-油液耦合失稳振动的自抑制机理研究”。.首先建立了航空发动机多场耦合动力学模型，推导等效耦合力的数学表达式，并以此为出发点开展数值仿真和实验研究工作。其次探索了发动机多场耦合振动机理、耦合故障力激励下的复杂结构动力学特征和多场耦合效应引发的转子失稳现象。然后揭示了发动机控制-结构耦合振动、油液-结构耦合失稳振动、结构-结构（不同构件）耦合振动、气动-结构耦合故障以及结构-结构（同一构件）耦合失稳振动的发生机理，探明了主要因素对振动特性的影响规律，确定了耦合振动的稳定边界。最后提出耦合故障识别准则以及失稳故障监测流程，可用于发动机耦合故障的监测与识别。并通过建模、仿真和实验的研究得到了各参数对耦合故障的影响规律。基于这些规律，提出发动机耦合失稳振动的“自抑制”方法，期望避免发动机运行过程中耦合振动失稳故障发生，为耦合失稳振动的“自抑制”提供原理和规律上的技术支撑。.研究中发现多场耦合故障中应力与应变之间存在的迟滞现象是导致失稳的重要因素，而自转角速度大于进动角速度的非协调进动是引起失稳的条件。基于上述结论对多场耦合失稳故障的机理进行统一表达；进一步总结出多域耦合失稳振动的特征即失稳早期就会出现次谐波成分，且次谐波成分为转子一阶临界转速的频率。这一结论已在套齿内摩擦耦合失稳实验以及盘腔液-构耦合失稳实验中得到验证。.本团队始终践行“将论文写在祖国的大地上”的理念。以上研究成果已培育国家重大科技专项基金项目1项；并已开展科研成果转化，所取得的成果正在转化落地，作为某型发动机机载和地面PHM系统的振动模块，预期五年之内将应用于火箭发动机涡轮泵振动分析以及水下热动力机械噪声源识别；在总结研究成果的过程中出版专著1本；研究中始终重视与工程实践紧密结合，获批国家发明专利7项，申请软件著作权2项。