Measurement of bubble sizes in fluidised beds using electrical capacitance tomography
Measurement of bubble sizes in fluidised beds using electrical capacitance tomography
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DOI：
10.1016/j.ces.2015.01.011
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发表时间：
2015-04-14
影响因子：
4.7
通讯作者：
Holland, D. J.
中科院分区：
文献类型：
--
作者：
Chandrasekera, T. C.;Li, Y.;Holland, D. J.
电容层析成像（ECT）提供了一种非侵入性成像多相流，如流化床中的手段。传统上，ECT图像是使用介电常数分布在整个传感器区域中平滑变化的假设来重建的。然而，对于许多应用来说，介电常数存在阶跃变化，例如，在流化床中的气泡相和颗粒相之间，并且平滑度的假设是有缺陷的。在这篇文章中，总变分迭代软介电常数保持（TV-1ST）算法被用来重建ECT图像，允许急剧过渡的介电常数分布。将该算法与已有的ECT图像重建算法进行了比较。结果发现，TV-1ST算法降低了敏感性的阈值水平时，提取测量的气泡尺寸从ECT数据集选择。在流化床中使用TV-1ST算法的气泡尺寸分布的测量值与气泡尺寸的经验相关性密切相关。结果表明，ECT可以提供准确的和高空间分辨率的气固流化床中的特征，如气泡的测量。(C)2015作者出版社：Elsevier Ltd
Electrical capacitance tomography (ECT) provides a means for non-invasively imaging multiphase flows, such as those in fluidised beds. Traditionally ECT images are reconstructed using the assumption that the distribution of permittivity varies smoothly throughout the sensor region. However, for many applications there are step changes in the permittivity, for example, between the bubble and particulate phases in a fluidised bed, and the assumption of smoothness is flawed. In this article a Total Variation Iterative Soft Thresholding (TV-1ST) algorithm is used to reconstruct ECT images that allows for sharp transitions in the permittivity distribution. This new algorithm has been compared with established algorithms for ECT image reconstruction. It was found that the TV-1ST algorithm reduced the sensitivity to the threshold level chosen when extracting measurements of bubble size from ECT data sets. Measurements of the bubble size distribution in the fluidised bed using the TV-1ST algorithm agreed closely with established empirical correlations for the size of bubbles. The results demonstrate that ECT can provide accurate and high spatial resolution measurements of features such as bubbles in gas solid fluidised beds. (C) 2015 The Authors. Published by Elsevier Ltd.