基体校正的能量色散X射线荧光光谱技术定量探测航空发动机滑油金属方法研究

Aircraft engine is just like the heart of the aircraft. Its physical condition will decide air safety directly. However, lubrication oil is just like aircraft engine blood and the composition, concentration of the metal in lubrication oil can reflect the performance states of it. Energy dispersive X-ray fluorescence spectroscopy (EDXRFS) technology provides a rapid and real time analysis method, comparing with traditional detection technologies which only detect one constituent or require preprocessing for the sample. But there are some difficulties for precise quantification that the one is matrix effect correction and the other is overlapping spectrum for coexistence components. This project will propose the solution and carry out research for these problems..The project will start with analyzing EDXRFS characteristics of the lubrication oil and its contained metal elements. Through the laboratory measurement, system parameters will be analyzed according to the detection sensitivity. Different lubrication oil will be studied which influence the EDXRFS intensity differently. The model of matrix effect correction will be built which combines the Compton scattering intensity with the mass-absorption coefficient. The method of frequency domain transformation and characteristic spectroscopy singularity communication will be researched for spectroscopy processing. It can resolve the problem of accurate separation of overlapping spectroscopy. The accurate inversion algorithm for multi-metal of lubrication oil will be established by the means of partial least squares. The correlation coefficient matrix of the model is improved. By this means, the absorption and enhancement effect of interelement is eliminated. The coming out project will provide a novel method for rapid and accurate detection of metal in aircraft engine lubrication oil.

航空发动机如同飞机的心脏，其健康状况直接决定了飞行安全，而滑油如同其血液，滑油所含金属的组成、含量等能够直接反映其性能状态。与传统检测成分单一或样品需预处理等技术相比，能量色散X射线荧光光谱（EDXRFS）技术提供了一种快速、实时分析方法，但目前该技术尚面临滑油基体效应校正以及由于共存组分光谱交叠而引起的精确定量化困难。本项目针对EDXRFS所面临的问题提出解决方案并开展研究。.项目从滑油及其金属EDXRFS特征入手，开展实验测量，优化系统设计，提高轻金属组分探测灵敏度。研究不同滑油基体对EDXRFS强度影响，建立基于康普顿散射强度与质量吸收系数的基体效应校正模型；研究采用小波包频域空间变换及特征谱传播方法处理光谱，解决交叠光谱精确分离难题；研究采用改进相关系数矩阵的偏最小二乘方法，建立滑油金属多组分定量反演算法模型，消除元素吸收增强效应，为航空发动机滑油金属快速、精确测量提供方法基础。

航空发动机如同飞机的心脏，其健康状况直接决定了飞行安全，而滑油如同其血液，滑油所含金属的组成、含量等能够直接反映其性能状态。与传统检测成分单一或样品需预处理等技术相比，能量色散X射线荧光光谱（EDXRFS）技术提供了一种快速、实时分析方法，但目前该技术尚面临滑油基体效应校正以及由于共存组分光谱交叠而引起的精确定量化困难。本项目针对EDXRFS所面临的问题提出解决方案并开展研究。.项目设计了EDXRFS检测装置，为完成滑油金属测量提供了条件。研究了测量装置对滑油金属检测的参数设置，确定其检测的激发电压为40kV、激发电流为20μA、脉冲整形峰值时间与宽度分别为6.4μs和0.2μs、快速阈值为10。为实现测量数据的去噪预处理，着重研究了小波包变换的分解层数选择和阈值设置，提出了小波包变换细节系数重构的奇异谱分析方法自适应选择分解层数；针对测量光谱的噪声水平自适应设置阈值，并采用改进的软阈值函数进行处理。对基体效应产生进行了分析，并对基体效应较为明显的基线进行校准，提出了小波高尺度分解的尺度系数区间基线校准方法。针对特征光谱小波分解系数特点，提出了基于模极大值传播的区间峰值位置识别方法，实现金属组分定性识别。.研究了偏最小二乘(PLS)回归方法在滑油金属EDXRFS定量解算中的应用。依据光谱强度与浓度得分向量间权重关系，对测量光谱强度进行了去相关校正；采用遗传基因算法实现了光谱变量的非线性寻优，并改进了个体适应度评价模型。完成了EDXRFS检测滑油金属的软件编制。研究结果为滑油金属EDXRFS检测提供了一定的理论与技术借鉴。