光纤动态检测三维叶尖间隙的航空发动机健康监测方法研究

The compressor and turbo machine are key components of aero-engine, whose tip clearance not only reflects the efficiency of aero-engine, but also shows the running state of the compressor and turbo machine inside the engine, which makes it necessary to measure the tip clearance of the compressor and turbo machine in order to monitor an aero-engine’s health status. This project intend to study an aero- engine health monitoring approach based on the optical fiber dynamic measurement on three-dimensional characteristic parameters of the tip clearance. According to this, a representation of three-dimensional features of blade tip clearance including the radial clearance, the deflection angle of the blade tip in shaft and circumferential direction is proposed, together with the dynamic mechanism model of three-dimensional tip clearance under all operating conditions. Then, a study on the three-dimensional tip clearance dynamic measurement technology using optical fiber is put forward along with compensation methods on aerodynamic interference .At last, an linear recognition algorithm model is designed to recognize the running state of the compressor and turbo machine based on the three-dimensional test results of tip clearance, according to which formed the final dynamic health monitoring model of aero-engine. The in-depth study of this project mainly aims at expanding and developing the technical and theoretical system of health monitoring technology towards aero-engine, along with improving its the safety and economic performance, that will offer a much more valuable scientific significance and engineering application prospects in the field of aviation.

压气机和涡轮是航空发动机的关键部件，其叶尖间隙的动态变化不仅影响航空发动机的工作效率，同时反映了航空发动机的安全状况，为此对叶尖间隙的动态精密检测是实现航空发动机健康状态监测的有效手段。本项目拟研究一种基于光纤动态检测叶尖间隙三维特征参量的航空发动机健康监测方法。其主要研究内容包括：提出叶尖间隙三维特征（径向间隙、周向滑移角、轴向偏转角）的表示方法，建立航空发动机全工况下的压气机、涡轮叶尖间隙三维特征参量动态变化机理模型；研究三维叶尖间隙的光纤动态精密检测技术，提出消除发动机全工况下气动干扰的软、硬件补偿方法；设计一种快速识别叶尖间隙三维检测结果的线性鉴别算法，研究基于叶尖间隙三维特征的航空发动机健康监测技术。该项目的深入研究，不仅能够丰富和发展航空发动机的健康监测技术理论体系，同时还能够提高航空发动机的运行安全性和经济性，具有重要的科学理论价值和工程应用前景。

航空发动机被称为飞机的“心脏”，涡轮和压气机是航空发动机的关键部件。涡轮和压气机叶片的工作环境非常恶劣，高压高转速的工作条件使得叶片极易出现裂纹等典型故障。叶片裂纹故障会导致其三维叶尖间隙发生变化，因此对涡轮和压气机叶片三维叶尖间隙进行实时在线监测，对于叶片裂纹故障的监测诊断，保障航空发动机的安全性和稳定性具有重要意义。由于涡轮叶片的工作环境及其所承受的载荷比压气机叶片更加复杂，因此涡轮叶片三维叶尖间隙测量方法对于压气机叶片三维叶尖间隙的测量也具有一定的适用性。为此，本项目以实现基于三维叶尖间隙的涡轮叶片健康监测为目标，首先，提出涡轮叶片三维叶尖间隙的概念，建立涡轮叶片三维叶尖间隙有限元分析模型，研究航空发动机典型工作载荷对三维叶尖间隙变化规律的影响，并在此基础上研究涡轮叶片尾缘裂纹故障特征参数对三维叶尖间隙变化规律的影响；其次，基于双圈同轴式光纤位移传感器，设计用于测量涡轮叶片三维叶尖间隙的光纤传感器，并研究该传感器的三维空间输出特性，并在此基础上，研究涡轮叶片三维叶尖间隙的光纤动态检测方法和精密解调方法，搭建涡轮叶片三维叶尖间隙的光纤动态检测系统；再次，以涡轮叶片三维叶尖间隙的动态测量信号为基础，研究涡轮叶片裂纹故障的监测诊断方法，实现对涡轮叶片裂纹的故障诊断及健康监测；最后，搭建涡轮叶片三维叶尖间隙的静态标定实验台和涡轮模拟转子实验台，对涡轮叶片的三维叶尖间隙的光纤动态检测方法和裂纹故障监测诊断方法进行实验验证。实验结果表明，本项目设计开发的三维叶尖间隙光纤动态检测系统能够对涡轮叶片三维叶尖间隙进行实时动态检测，所提出的涡轮叶片裂纹故障监测诊断方法能够准确诊断出涡轮叶片早期裂纹故障，并且具有较好的稳定性和泛化能力。本项目的开展为航空发动机涡轮叶片的故障诊断提供了新的思路，丰富了涡轮叶片裂纹故障的监测诊断方法，为扩展航空发动机健康监测理论体系奠定了基础。