modelingofcocurrentandcountercurrentbubblecolumnswithanextendedemmsapproach

Bubble columns can be operated in semi-batch, co-current or counter-current mode. This study attempts to extend the dual-bubble-size (DBS) model, viz., the energy-minimization multi-scale (EMMS) model for gas-liquid systems, to co-current and counter-current bubble columns. With the increase of superficial liquid velocity, the predicted total gas holdup and regime transition are in accordance with experiments. A DBS drag model was then developed and incorporated into the CFD simulation. The total gas holdup and local gas holdup radial distribution in both the co-current and counter-current bubble columns are well estimated. The findings in the present work demonstrate that developing closure laws through the stability condition is of great significance in modeling complicated multi-scale flow in bubble columns. (C) 2019 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved