【作者】 阎春生；

【导师】 廖延彪；

【作者基本信息】 清华大学 ， 物理电子学， 2003， 博士

【摘要】 光纤过程层析成像是光纤传感领域的一门新型技术，具有光纤传感器的测量低浓度物质分辨率高、体积小、抗电磁干扰以及可以进行分布式测量的共同优点和可以同时测量物质截面内部结构的独特优点，在多相流动广泛存在的石油、化工、能源等工业部门和医疗、卫生、食品等领域具有广泛的应用前景，对监控产品质量、降低成本以及保证生产安全具有非常重要的意义。本论文在总结前人工作的前提下，充分兼顾了工业中具有圆形截面的圆柱形容器或管道普遍存在的事实，提出了一种新型的光纤过程层析成像结构，并从理论设计方法，具体结构仿真，平面结构实验系统设计，初步实验以及空间结构实用化设计、理论分析等方面进行了研究，主要的创新点在于：⑴提出了一种用于工业过程监测与控制的新型光纤过程层析成像结构设计方法，并推导了该方法的经验公式，该方法主要包括像素分配和平面光路结构设计，可以根据工程应用中图像重建的分辨率和圆形截面非测量区域所占比例的要求，设计所需传感单元的数目和传感单元发射光线的数目；⑵ 设计了一种新型的光纤过程层析成像结构，并对该结构进行了可行性分析和数值仿真。该结构的主要特征为：8个光纤传感单元均匀分布于截面圆周，每单元收发各3条光线，覆盖具有60个象素的环形测量区域，中心圆形非测量区域放置系统的支撑结构；⑶ 完成了平面结构的实验系统，通过设计其中的关键元件－光学窗口，成功解决了光路通光、容器壁反射以及容器内外密封的实际问题，并在此基础上对光纤准直器、光电探测器以及光学窗口在容器壁的定位进行了计算，所有24路光通道由于精确计算和加工一次调试成功；⑷ 对新型结构进行了初步实验研究，实验结果表明该结构能对气－固两相物质分布进行测量和图像重建。⑸ 设计了实用化的新型空间光路结构，经过详细的理论分析与计算，给出了该结构的定位精度，结果表明整个系统对结构各部分的定位精度不高，为新型光纤过程层析成像结构的实用化提供了理论依据。更多还原

【Abstract】 Optical fiber process tomography (OFPT) is a new technology in the field of optical fiber sensor (OFS). The probe of OFPT is small, safe, free of electromagnetic interference and has high sensitivity in low-density medium case same as OFS, more important and different is that it can detect the medium distribution and contents of the cross-section to be investigated simultaneously, which makes OFPT show potential and extensive applications in petroleum, chemical, energy, medicine, food and sanitation fields to control product quality, realize safe production and reduce the cost. On the premise of summarizing former contributions in the field, and considering the universality of the cylindrical space with circular cross-section in industry, the author develop a novel OFPT structure, on which the design theories, numerical simulation, design of experimental system for plane structure, preliminary experiment and design of applied space structure are presented. The main contents of the thesis are that:Put forward the novel OFPT pixel distribution and plane-light-path design theories and their empirical formulae. The numbers of the OFS units and their emitting rays can be decided by the requirements of image-reconstructed resolution and the size of the center unmeasured region.Develop a novel OFPT structure by the theories and simulate it by algebraic iterative reconstruction algorithm (ART). The structure includes eight OFS units uniformly distributed around the circle, where each unit emits three rays to the clockwise adjacent three units and receives three rays from counterclockwise adjacent three units. Rays cover all sixty pixels of the measured ring region. The center circular region belongs to unmeasured part for the back-up structure of the system.Design and manufacture the OFPT experimental system. Many practical problems such as waterproof, light passing and wall optical reflection are successfully solved<WP=7>by specially designing an optical window, thus the positions of all optical devices such as optical fiber collimators, detectors and the windows are calculated accurately to make the collimation of all optical channels simply and easily. Take the elementary experiments and use genetic algorithm in the image reconstruction. The results show that the novel OFPT system can measure and reoccur some gas-solid two-component distributions.Design and analysis the applied space OFPT structure. The positioning accuracies of all devices and the whole system are figured out. The results show that processing and positioning requirements to optical devices in the space structure are not too high.更多还原