Abstract In this paper, the effects of dense vertical internals (rods) on gas holdup and local gas and liquid velocities were investigated by using the Eulerian-Eulerian model coupled with the population balance model. The inclusion of lift and wall lubrication forces was studied by applying different models. The results indicated that just by choosing the appropriate interfacial forces, the numerical model agrees well with the experimental data. A sharper gas holdup, a stronger gas velocity gradient, and a more intense liquid recirculation were observed as the important impacts of the internals. Moreover, three circular internals’ arrangements were considered to study the effect of wall and core clearance distances on the bubble column hydrodynamics. The results revealed that by increasing the wall clearance distance, flatter gas holdup and velocity distributions could be achieved. Also, the turbulence parameters were used to evaluate the capability of the model in the prediction of the bubble size distribution. A modification factor for the breakage and coalescence kernels was proposed; the factor enabled the model to reach equilibrium mean diameters for bubbles. The comparison of the probability distribution function (PDF) of bubble sizes in the bubble column with and without internals showed a narrower bubble size distribution with a smaller mean diameter in the presence of internals.

中文翻译：

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密集垂直内部构件对气泡柱中流体动力学和种群平衡模型影响的综合 CFD 研究

摘要 本文利用欧拉-欧拉模型结合种群平衡模型研究了致密垂直内构件（棒）对含气率和局部气液速度的影响。通过应用不同的模型研究了升力和壁面润滑力的包含。结果表明，仅通过选择合适的界面力，数值模型与实验数据吻合良好。作为内部构件的重要影响，观察到更急剧的气体滞留、更强的气体速度梯度和更强烈的液体再循环。此外，考虑了三个圆形内部构件的布置来研究壁和核心间隙距离对气泡柱流体动力学的影响。结果表明，通过增加壁面间隙距离，可以实现更平坦的气体滞留率和速度分布。此外，湍流参数用于评估模型预测气泡尺寸分布的能力。提出了破碎和聚结核的修正系数；该因子使模型能够达到气泡的平衡平均直径。有和没有内件的气泡柱中气泡尺寸的概率分布函数 (PDF) 的比较表明，在有内件的情况下，气泡尺寸分布更窄，平均直径更小。该因子使模型能够达到气泡的平衡平均直径。有和没有内件的气泡柱中气泡尺寸的概率分布函数 (PDF) 的比较表明，在有内件的情况下，气泡尺寸分布更窄，平均直径更小。该因子使模型能够达到气泡的平衡平均直径。有和没有内件的气泡柱中气泡尺寸的概率分布函数 (PDF) 的比较表明，在有内件的情况下，气泡尺寸分布更窄，平均直径更小。