An Experimental Study on Velocity Characteristics of the Slug Flow in Gas-Liquid Pipe Flows

Slug flow is commonly encountered in industrial flows, its characteristics like strong intermittence and high pressure drop are usually harmful to the industrial process and facilities. Slug flow has more characteristic parameters than other flow regimes, and the fluctuation of these parameters makes it more difficult for their study. This paper investigates the velocity characteristics of slug flow via the fast electrical impedance tomography technique. First, the images of a series of gas-liquid slug flows in the vertical upward pipe are collected and reconstructed, then the velocity distributions of different regions are calculated by the cross-correlation algorithm. After that, the different regions in slug flow are distinguished based on image analysis, and the leading-edge velocity of Taylor bubbles is acquired. Finally, the velocity characteristics are analyzed and compared with the calculated result of the theoretical model and empirical formula. This study indicates that the fast electrical impedance tomography technique is capable of reconstructing the flow structure images, and acquiring the key velocity parameters in slug flow, which can be used to verify and improve the relative theoretical models and empirical formulas, thus is beneficial for improving the precision of the slug flow model.