CFD simulation of a slurry bubble column: Effect of population balance kernels
CFD simulation of a slurry bubble column: Effect of population balance kernels
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DOI：
10.1016/j.compfluid.2018.07.009
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发表时间：
2018-10
影响因子：
2.8
通讯作者：
Alizeb Hussain Syed;M. Boulet;Tommaso Melchiori;J. Lavoie
中科院分区：
文献类型：
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作者：
Alizeb Hussain Syed;M. Boulet;Tommaso Melchiori;J. Lavoie
本文对浆态鼓泡塔进行了CFD模拟，并与实验数据进行了验证。实验中考察的表观气速分别为5 cm/S和8 cm/S，在内径为0.14 m~0.26 m的色谱柱中，固相负荷在7%~14%之间变化。实现了一个种群平衡模型(PBM)，并用气泡类方法进行了数值求解。闭合核包括罗的合并模型以及两种不同的分手模型：罗的和莱尔的模型。采用颗粒流动力学理论(KTGF)计算了局部固体粘度。多相计算采用欧拉框架，气液相间动量传递包括阻力项、升力项和湍流弥散项。液-固界面上既有阻力项又有湍流弥散项。结果表明：(A)结合罗合核和罗解核(罗罗核)可以预测实验中固体轴向速度径向分布的相似趋势。然而，在小柱内的最高表观气速时，结果却有所不同。(B)与经验数据相比，Luo聚结和Lehr裂解核(Luo-Lehr)的组合预测了固体速度的相似趋势，然而，在小柱子中测试的最高表面速度处，这种组合也显示出不同的结果。(C)与实验结果相比，罗罗模型和罗莱尔模型的总气含率分别偏低和偏高。(D)网格敏感性计算结果表明，采用3 mm的网格尺寸来捕捉流场是可行的。(E)对气泡级别数量的敏感性分析表明，径向轮廓与一些气泡级别无关。然而，最多的班级涵盖了最大气泡的形成。
In this work, CFD simulations of a slurry bubble columns were performed and validated with experimental data. The superficial gas velocities investigated in the experiments were 5 cm/s and 8 cm/s for a solid loading varying from 7% to 14% in a 0.14 m to 0.26 m internal diameter column. A population balance model (PBM) was implemented and solved numerically using the bubble class method. The closure kernels involved Luo's coalescence model as well as two different breakup model: Luo's and Lehr's models. The kinetic theory of granular flows (KTGF) was used to calculate the local solid viscosity. The Eulerian framework was selected for multi-phase calculations and the interphase momentum transfer for gas–liquid included drag, lift, and turbulent dispersion terms. The liquid–solid interphase involved both drag and turbulent dispersion terms. Results showed that: (a) A combination of the Luo coalescence and Luo breakup kernels (Luo–Luo) can predict similar trends for the radial profile of solid axial velocity with regards to experiments. However, at the highest superficial gas velocity in the small column, a discrepancy was observed in the results. (b) A combination of the Luo coalescence and Lehr breakup kernels (Luo–Lehr) predicted similar trends for the solid velocities when compared to empirical data, however, this combination also showed discrepancy at the highest superficial velocity tested in the small column. (c) The total gas holdup in the Luo–Luo and Luo–Lehr models are under and over predicted respectively when compared with the experimental results. (d) The mesh sensitivity results showed that a 3 mm mesh size is realistic to capture the flow fields. (e) The sensitivity analysis of the number of bubble classes showed that the radial profiles were independent to a number of bubble classes. However, the highest number of classes cover the formations of the largest bubbles.