场聚焦电容/电阻双模态成像方法研究

Multiphase flows widely exist in oil, chemical, metallurgical, power and food industries, in which online flow pattern identification and process parameters are vital important for scientific researches and industrial safety and efficiency. Due to the characteristics of complexity, randomness and variability, it is quite a challenging job to carry out accurate measurement of multiphase flows. Having advantages of being non-intrusive, non-radioactive and rapid response, electrical tomography becomes a promising online 2D/3D visualization tool for multiphase flow measurement. However, the tomographic images are always distorted by the 'soft-field' and ill-posedness charateristics of electrical tomography. Therefore, the applicants suggest a field-focusing imaging method, which features sensitivity field-focusing and direct imaging. Moreover, it retains the advantages of electrical tomography. The research scope of this project includes the measurement and imaging mechanisms of field-focusing imaging sensor, optimization of sensor parameters and excitation/detection scheme, non-ideal field-focusing image reconstruction, and integration of ECT/ERT dual modality measurement method to implement a field-focusing imaging measurement system. The project will result in a novel field-focusing imaging method, which has a promising prospect in multiphase flow measurement.

多相介质的混相流动广泛存在于石油、化工、冶金、电力、食品等工业中，而多相流在线流型辨识及相关参数提取，对科研及工业生产的安全、高效运行具有重要意义。由于多相流具有复杂、随机和瞬态的特点，实现多相流的准确测量非常困难。电学成像方法具有非侵入、无辐射以及响应快速的特点，为多相流研究提供了一种实时在线的2D/3D可视化监测方法；然而，电学成像受'软场'、病态性等困扰，重建图像存在较大失真。申请者所提场聚焦成像方法具有敏感场聚焦以及直接成像的特点；同时，保留了电学成像技术已有优势。本项目拟研究场聚焦成像方法的检测及成像机理，建立流场分布与测量数据之间的映射模型；在此基础上优化传感器结构及激励/测量模式；研究非理想聚焦情况下的成像方法，获取高分辨率图像；融合电容/电阻双模态测量方法，建立数字化测量系统。本课题的成果将形成一种新的场聚焦成像方法，在多相流测量领域应用前景巨大。

电学成像技术的主要优势包括：本质安全、无核素辐射、响应快速、可适用各种复杂工况（如高压、高温、有毒或辐射环境）、使用成本低，可长时间在线监测工业过程或作为医学临床监护手段；与此同时，其受‘软场’特性及逆问题欠定性的困扰，图像空间分辨率相对较低且图像解释困难，成为其工业、医学应用推广的主要障碍。本项目主要研究流场分布与测量数据之间的映射模型；在此基础上优化传感器结构及激励/测量模式；研究非理想聚焦情况下的成像方法，获取高分辨率图像；融合电容/电阻双模态测量方法，建立数字化测量系统。在场聚焦成像系统的传感器设计、成像算法和实时信号处理方法等方面取得有益成果。在此基础上，探讨双模态场聚焦测量方法在一些多相流测量中的应用。