基于ECT的航空发动机尾气监测系统设计与实现

发布时间：2018-04-11 19:02

  本文选题：航空发动机 + 电容层析成像　； 参考：《中国民航大学》2016年硕士论文

【摘要】：航空发动机(aero-engine)作为飞机的重要组成单元,它的结构复杂特殊,运行环境恶劣,工作状态切换频繁。这些因素都极易给发动机带来磨损和损耗,严重时会导致其工作失效,造成航空事故,危害飞机的飞行安全和人的生命安全。因此对飞机尾气的监测具有重大意义。本文利用电容层析成像(Electrical Capacitance Tomography,ECT)技术对模拟aero-engine尾喷管处的尾气进行气路监测,以获取实时图像,监测尾管内气固两相流的流动情况和颗粒信息,为发动机维修提供参考依据。ECT技术是目前最为成熟的一种电学层析成像(Electrical Tomography,ET)技术。该技术具有无辐射、非侵入、可靠性高、实时性强以及成本低等优势,但因空间分辨较低所以在稀相流的测量中应用较少。为了深入研究aero-engine的尾气情况,以便对aero-engine做出故障诊断,本文研制了一套ECT硬件采集系统,通过ECT技术对aero-engine尾气进行测量研究,做的主要工作以及获得的结果如下:1.分析研究并吸收ECT传感器的研究成果,根据aero-engine喷尾管实际模型和传感器结构优化,设计了一套基于16电极的圆周形ECT传感器。2.通过分析ECT传感器物理敏感场的特性,提出其数学描述,并通过二维有限元方法求解ECT的正问题以及分析ECT的逆问题。3.研制一款16电极圆周形传感器的ECT硬件采集系统。该系统是在吸收前人研究的基础上进行改进,采用Xilinx的FPGA作为核心处理控制单元,通过数字解调的方法,提高了系统的实时性;在输入信号频率和幅值不变时,采用量程更小和转换速度更快的ADC;系统PCB的布局,融入了信号完整性(Signal Integrity,SI)、电源完整性(Power Integrity,PI)以及电磁兼容性(Electro Magnetic Compatibility,EMC)的设计理念,使系统硬件设计更加合理,优化程度更高。4.借助线性反投影算法(Linear Back Projection,LBP)和Landweber迭代算法两种经典ECT成像算法,再结合设计的ECT硬件采集系统,进行实时成像,从而验证硬件采集系统和软件系统的性能。结果表明,该系统性能稳定、重建图像清晰可见以及可拓展性强。
[Abstract]:Aero engine (aero-engine) as an important component of the aircraft, its structure is complex and special, harsh working environment, working condition of frequent switching. These factors are easy to bring the engine wear and tear, it will lead to serious failure, caused by aviation accidents, endangering flight safety and the safety of human life. So monitoring the aircraft exhaust is of great significance. This paper using electrical capacitance tomography (Electrical Capacitance Tomography ECT) technology to simulate aero-engine exhaust nozzle of gas path monitoring, to obtain real-time image monitoring, the tail pipe of gas-solid two-phase flow in the flow and particle information, provide reference for engine maintenance technology is.ECT at present, one of the most mature electrical tomography (Electrical Tomography ET) technology. This technology has no radiation, non-invasive, high reliability, real-time and The advantages of low cost, but because of low spatial resolution measurement so in dilute phase flow in application. In order to study the emission of aero-engine, in order to make fault diagnosis of aero-engine, this paper develops a set of ECT hardware acquisition system was studied by ECT technology of aero-engine tail gas, the main work done and get the the results are as follows: 1. research results and analysis of the absorption of the ECT sensor, according to the aero-engine model and the actual injection tail pipe sensor structure, design a set of circle shaped ECT sensor.2. 16 electrode based on ECT sensor by analyzing the physical characteristics of sensitive field, put forward the mathematical description, and through the two-dimensional finite element method to solve the problem is ECT and ECT analysis of the inverse problem of.3. development of a 16 electrode circle sensor ECT hardware acquisition system. The system is on the basis of previous studies Improved, using Xilinx FPGA as the core processing control unit, through the method of digital demodulation, improves the real-time performance of the system; the frequency and amplitude of the input signal is constant, the range of smaller and faster switching speed ADC; PCB system layout, integrated signal integrity (Signal Integrity SI), power integrity (Power Integrity, PI) and electromagnetic compatibility (Electro Magnetic, Compatibility, EMC) design concept, the system hardware design is more reasonable, optimize the higher degree of.4. with the linear back projection algorithm (Linear Back Projection, LBP) two classic ECT imaging algorithm and Landweber iterative algorithm, combined with the ECT acquisition system hardware design. Real time imaging, so as to verify the performance of the hardware system and software system. The results show that the system has stable performance, the reconstructed image is clearly visible and strong expansibility.

【学位授予单位】：中国民航大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：V263.6;TP274
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本文编号：1737276