Characterisation of gas–liquid two-phase flow inside capillaries

• Published in: Chemical engineering science 1999-12, Vol.54 (23), p.5723-5735
• Main Authors: Laborie, S., Cabassud, C., Durand-Bourlier, L., Lainé, J.M.
• Format: Article
• Language: English
• Subjects: Applied sciences; Chemical and Process Engineering; Chemical engineering; Engineering Sciences; Exact sciences and technology; Fluid dynamics; Fundamental areas of phenomenology (including applications); Hydrodynamics of contact apparatus; Multiphase and particle-laden flows; Nonhomogeneous flows; Physics
• ISSN: 0009-2509; 1873-4405
• DOI: 10.1016/S0009-2509(99)00146-3

Continuous gas sparging inside ultrafiltration hollow fibres (with the feed) has been shown to be effective in enhancing permeate flux by reducing particle deposit on the membrane wall. The present study focuses on the hydrodynamic characterisation of gas–liquid two-phase flow inside glass capillaries in order to understand the mechanisms involved in the process improvement. In capillaries of inner diameter less than 4×10 -3 m, experiments showed that the flow consisted of a slug flow: a succession of gas and liquid slugs rising up the pipe. As very few data are available concerning this type of flow, it was visualised inside the glass capillaries so that its characteristics could be observed. Gas slug velocity, which is different from the mean velocity of the flow, was calculated and a linear relationship found between the two velocities. Gas and liquid slug lengths and frequency were determined and plotted versus operating parameters such as gas and liquid superficial velocities, capillary inner diameters and fluid properties.