静电层析成像技术(EST)是应用于气固两相流动参数检测的一种新兴技术.利用颗粒荷电的特性,静电层析成像技术可以实现对流动颗粒的流型识别以及速度分布的测量.首先针对影响EST的灵敏场进行研究,发现基于现有等网格灵敏场的正则化算法对于中心区域电荷反演效果较差,通过分析灵敏场对EST的影响,进而提出全新的非等网格灵敏场,结果表明该方法可以很好地重建中心区域的电荷分布,但存在的缺点是降低图像的空间分辨率.为此通过对EST图像重建算法中灵敏场作用的分析,从而提出采用BP算法实现中心区域图像重建.实验结果表明非等网格灵敏场和BP算法都取得了良好的效果.
Electrostatic tomography (EST) is a novel technology for the measurement of the flow parameters of gas-solid two-phase flow. Based on particle charging, EST can achieve flow regime identification and velocity profile measurement through detecting the flowing charged particles. Firstly the effect of the sensitivity map on EST was investigated. The results indicate that with the equal-mesh sensitivity map based regularization algorithm, the charge inversion effect in the center region of the EST sensor is poor. Through analyzing the effect of sensitivity map on EST, a novel unequal-mesh based sensitivity map was proposed to solve the problem. The result indicates that the proposed method can reconstruct the charge distribution in the center region well ; however the spatial resolution of the reconstructed image is decreased. Through analyzing the function of the sensitivity map in EST image reconstruction algorithm, the BP algorithm is proposed to realize the image reconstruction in the center region. The experiment results show that the unequal-mesh based sensitivity map and BP algorithm both achieve satisfied results.