多通道激光自混合测量方法及高分辨率三维流速传感技术研究

Compared to the traditional Michelson and Mach-Zehnder interferometers, this laser self-mixing sensing technique has many advantages, such as simple operation, compact and easy to adjust, etc. But commonly this technique can only realized the one-dimensional or one-point physical parameter measure by using one laser diode, and it is difficult to meet the rapid monitoring needs of the three-dimensional flow rate of the nanoscale particles in complex flow field. So, this project proposes several simple and feasible methods to measure the three-dimensional flow rate and the other physical parameters of several points based on multi-channel laser self-mixing effect. Moreover, the problems of multi-channel LSM signal coupled three-dimensional flow rate can be solved during the measurement..First, this project will develop the theoretical model of self-mixing effect with multi-channel feedback by using three-mirror theory, and analysis the relationship between the key parameter and the self-mixing signal. Second, both the method by using FP etalon and triangular current modulation and the method by using fiber optic beam splitter and square-wave modulation will be investigated in detail. Last, the multi-channel self-mixing systems will be established to measure the three-dimensional fluid velocity and displacements of several points. The fundamental principle of multi-channel self-mixing effect will be summarized according to the theoretical and experimental results. The work is the theoretical and technological basis to realize sub-micron particles monitoring. It is hoped to promote innovation and technological development of the laser self-mixing technique by this work.

激光自混合（LSM）技术相对于传统的干涉测量技术具有结构简单、紧凑、易准直等优点。通常单套LSM系统仅能获取一维速度等信息，难以满足复杂流场内纳米级颗粒物的三维流速灵敏快速监测需求。为此，本项目提出多种简便可行的基于多通道LSM效应的高分辨率多维流速和多点物理量测量方法，解决多通道LSM信号相互耦合时三维流速难以提取等问题。.本项目将从理论分析着手，基于Lang-Kobayashi理论建立多通道激光反馈下的LSM理论模型，模拟分析激光波前、频率等参数与自混合信号的影响关系；提出基于三角波电流调制和光纤分束、基于方波电流调制和FP标准具分光的多通道LSM测量方法，系统性分析并验证光束波前、光频率、调制幅度和频率等对自混合信号的影响；建立多通道LSM传感系统，实现三维流速和多点位移的准确测量。最后结合理论模拟和实验研究结果，建立较完善的多通道LSM理论，推动LSM测量方法革新和技术发展。

激光自混合（LSM）技术相对于传统的干涉测量技术具有结构简单、紧凑、易准直等优点。通常单套LSM系统仅能获取一维速度等信息，难以满足复杂流场内纳米级颗粒物的多维流速灵敏快速监测需求。.本项目的主要研究内容包括，多通道光反馈下激光自混合理论，系统参数对激光自混合信号的影响；多通道激光自混合测量方法；搭建实验平台，分析多通道激光自混合信号的变化规律，实现多通道激光自混合信息传感。取得的重要成果和数据如下。.1）建立多通道光反馈下激光自混合理论模型，理论分析和数值模拟了不同激光器参数条件下的自混合信号变化特征，分析激光自混合信号随激光波长、激光器腔长、工作物质折射率的变化规律。.2）建立了多套多通道激光自混合传感系统，实现了角度和振幅、速度和位移、多维速度的同步测量，实现了矩形管道层流流速分布的准确测量；具体实现了0.990°到1.029°的角度范围和0到3000mVpp的振动范围，角度和振动测量误差分别优于12.1%和1%，测量精度可达387.5nm；实现了0.016到0.47m/s的速度范围和1到23mm的位移范围，速度和位移误差分别优于5.3和9.8%；得到了矩形管道层流流速分布，实验测量的流速与理论流速值偏差在3%以内。.3）已发表SCI/EI论文11篇，申请发明专利3项（已授权2项），已培养博士1名、硕士2名。.本项目的研究工作，有助于深刻理解多通道反馈下激光自混合效应机理，为高空间分辨率的多维流速和多点位移等测量领域奠定理论与技术基础，具有重要的理论意义和应用价值。

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