Electrogenerated bubbles induced convection in narrow vertical cells: A review

The present paper focuses on Vertical Plane Electrode Reactors with Gas Electrogeneration, VPERGEs, which are involved in various industrial applications in large scale productions. It is well known that the efficiency of such electrochemical reactors is closely linked to the hydrodynamics of the electrogenerated bubbles which act as moving electrical insulators. Therefore, an accurate understanding of the two-phase flow hydrodynamics in these reactors is of prime importance to optimise their geometry and operation. However, the small inter-electrode space in VPERGEs is problematic for both experimental and numerical (CFD) investigations. In fact, because of the narrowness of the gap separating the electrodes, many key aspects of the multiphase flow field are inaccessible to experimental measurements, while on the other hand, CFD models typically used nowadays are at the limit of validity. This paper presents a review of articles dealing with experimental and numerical investigations of the flow in VPERGE reactors that were classified into four reactors type depending on their geometry and on the operating conditions. Such classification is necessary to enable extracting general information on the flow features. Focus is put in particularly on the advantages and drawbacks of the experimental techniques and numerical approaches encountered in the literature. (C) 2015 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.