Drag model is of critical importance for CFD simulation of flow characteristics in bubble columns. In this study, a novel drag model termed DBS-Local for the ratio of effective drag coefficient to bubble diameter is derived from the Dual-Bubble-Size (DBS) model based on Energy-Minimization Multi-Scale (EMMS). A thorough comparison demonstrates that without adjustable parameters, both the DBS-Local model and the DBS-Global model are capable of improving the prediction of total and local gas holdup as well as the flow characteristics in different flow regimes. By contrast, other drag models either overestimate or underestimate the total or local gas holdup in certain flow regimes. Moreover, the centerline liquid velocity predicted by DBS-Local model shows best agreement with experiments, whereas the other models, especially the Ishii-Zuber model, over-estimate liquid velocity. This study demonstrates the significance of modeling the bubble-swarm effect based on EMMS approach.

阻力模型对于气泡塔内流动特性的CFD模拟至关重要。在这项研究中，基于能量最小化多尺度（EMMS）的双气泡尺寸（DBS）模型推导了一种新颖的阻力模型，该模型称为有效阻力系数与气泡直径之比的DBS-Local。彻底的比较表明，在没有可调参数的情况下，DBS-Local模型和DBS-Global模型都能够改善对总气体和局部气体滞留量以及不同流态下的流动特性的预测。相比之下，其他阻力模型在某些流态下要么高估要么低估了总的或局部的气体滞留量。此外，DBS-Local模型预测的中心线液体速度与实验显示出最佳一致性，而其他模型，尤其是Ishii-Zuber模型，高估了液体速度。这项研究证明了基于EMMS方法对气泡-群效应进行建模的重要性。