Investigation of Liquid Film in Horizontal Slug Flow Based on the Image Processing

Intermittent slug flow pattern commonly occurs in industrial processes, including petroleum, nuclear and chemical fields. Therefore, it is important to measure its characteristic parameters. The aim of this paper is to measure the liquid film thickness under elongated bubbles based on laser-induced fluorescence method. A new image processing procedure is developed to extract the axial liquid film thickness. To improve the robustness of the method, image enhancement and threshold segmentation algorithms are developed respectively. Based on the statistical analysis method, the influence of superficial gas-liquid velocity on the liquid film thickness is discussed. Furthermore, the frequency domain features of the liquid film thickness are also used to characterize the flow pattern transition from plug flow to slug flow. Finally, the experimental results show that the measured liquid film thickness is higher than the model predictions, and the relative error is within 8.6%.