Imaging of a Distinctive Large Bubble in Gas-water Horizontal Flow Based on Size Projection Algorithm

Electrical resistance tomography was succeed in being applied on gas-liquid two-phase flow, but it is incapable on determination of sharp interfaces between gas and water, which impedes effective estimation of fluid characteristics and flow regimes. Thresholding value method was demonstrated an abstractive view of most flow regimes, particularly a large bubble with a shape intermedium boundary. In principle, the thresholding values should be based on bubble merging principles, but is determined empirically in most practices, which may present a challenge in correctness. In this paper, a size projection algorithm is proposed for imaging a large bubble with distinctive boundary by searching an optimal thresholding value, which may provide a better estimation of the bubble size. Results from experiments engaged with typical gas-liquid flow regimes, including stratified, plug, slug and annular flow regimes, with large air cavity in a 50mm-diameter horizontal pipeline are reported in the paper, which especially focuses on imaging of the size of large bubble with the proposed method. The results are also compared with the images obtained from wire-mesh sensor system and videos taken from a transparent section of the test rig.