基于ECT/EST双模成像的滑油在线监测方法研究

With energy security, production safety and environment safety being taken as our national strategy, the research and application of aircraft engine condition monitoring technique is becoming increasingly important. Study of real-time oil monitoring method for aircraft engine is conductive to improving the safety and reliability of engine operation, and reducing the likelihood of abrupt failures especially catastrophic failures, and thus has great practical significance to national defense and people's livelihood. Electrical tomography (ET) has the advantages of non-destructive measuring, real-time imaging, low cost and non-nuclide radiation, by designing small scale electrical capacitance tomography (ECT) sensor according to the structure of the scavenge side of the lubrication system, and reconstructing the permittivity distribution of the oil in real time, the flow status, degradation degree of the oil and the wear pattern of the equipment can be detected online; to compensate for the inherent low spatial resolution of ECT, electrostatic tomography (EST) technique is developed on the basis of ECT sensor and the information of the charged wear particles in the oil is captured based on the electrostatic induction principle, to provide early warnings for abnormal wear failures of aero-engine; this project intends to design an ECT/EST dual modality imaging system and develop corresponding dual modality image reconstruction algorithms with reference to the application, by fusing information obtained from the two imaging mechanisms, i.e. ECT and EST, visualized oil monitoring with relatively high accuracy can be expected, and a novel online monitoring method can be provided for oil monitoring.

随着能源安全、生产安全及环境安全上升到国家战略高度，发动机状态监测技术的研究与应用日益凸显重要。开展航空发动机油路实时监测方法研究，能够提高发动机运行的安全性和可靠性，减少突发性故障尤其是灾难性故障的发生，对国防民生都具有重大现实意义。电学成像（ET）技术具有非侵入测量、实时成像、低成本、无核素辐射等优势，根据润滑系统回油路结构设计小尺度电容成像（ECT）传感器，通过实时重建油液介电常数的分布情况，在线观测滑油流动状况、劣化程度和设备的磨损情况；为补偿ECT固有的低空间分辨率，在ECT传感器的基础上研究静电成像（EST）方法，基于静电感应原理获取油液中的带电磨粒信息，为发动机异常磨损故障提供预警；设计ECT/EST双模成像系统，并结合应用对象开发双模态成像算法，通过融合电容、静电两种成像机理获取的信息，实现较高精度的滑油系统可视化监测，为滑油监测提供一种新型在线监测方法。

本课题针对电学成像（ET）技术在航空发动机滑油在线监测中的应用，制订了具体的研究方案：研究电容层析成像（ECT）技术用于滑油劣化程度监测；研究静电层析成像（EST）技术用于油液中的磨粒荷电信息监测；融合双模信息为滑油在线监测提供一种新型、便捷、低成本、可视化监测方法。设计了基于静电感应原理和基于电容敏感探测机理的双模态传感器，搭建了滑油监测模拟实验平台并进行实验，探究了基于ET技术的发动机回油管道特殊两相流的在线监测方法。在分析航空发动机润滑系统回油路中荷电颗粒的来源及其荷电机理的基础上，根据滑油管道结构，利用Comsol有限元分析软件，进行了传感器的3D建模、仿真及优化设计；综合考虑空间噪声和耦合效应，设计了弱信号探测及处理的软、硬件模块；为提高监测精度，进行了ECT和EST图像重建算法的深入研究，包括灵敏度矩阵的优化、结合应用对传统算法的改进和新型正则化方法研究。最后，基于研究结论提出了系统进一步改进的思路并进行了初步探索。