Modelling of mass transfer for gas-liquid two-phase flow in bubble column reactor with a bubble breakage model considering bubble-induced turbulence
Modelling of mass transfer for gas-liquid two-phase flow in bubble column reactor with a bubble breakage model considering bubble-induced turbulence
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DOI：
10.1016/j.cej.2019.04.047
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发表时间：
2019-09
影响因子：
15.1
通讯作者：
Weibin Shi;Xiaogang Yang;M. Sommerfeld;Junliang Yang;Xinyue Cai;Guang Li;Y. Zong
中科院分区：
文献类型：
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作者：
Weibin Shi;Xiaogang Yang;M. Sommerfeld;Junliang Yang;Xinyue Cai;Guang Li;Y. Zong
采用粒子数平衡模型(PBM)计算气泡与载液界面的传热传质时，湍流涡与气泡团相互作用的定量描述是预测气泡尺寸分布的关键。目前所采用的破碎核函数大多聚焦于液体中的剪切湍流，并使用经典的单相湍流Kolmogorov−5/3标度定律来模拟撞击气泡的到达涡中包含的动能。在鼓泡塔中，与气泡碰撞并导致气泡破裂的涡流主要是由气泡诱导的湍流(BIT)产生的。本文主要研究了气泡诱导的湍流能谱的κ−3尺度对鼓泡塔内气泡涡流碰撞所致气泡破裂的影响。提出了一种修正的考虑气泡诱导湍流的破碎模型。该模型考虑了气泡诱导的湍流影响下的涡旋平均湍流速度，以及与BIT相对应的特征波数/长度尺度。模拟结果与实验数据的对比表明，修正后的破碎模型较好地描述了鼓泡塔内气泡诱导湍流的影响下发生的气泡破碎事件。结果还表明，气泡与气泡诱导的湍流涡的相互作用对鼓泡塔内传质的预测有影响。
A quantitative description of the interaction between the turbulence eddies and bubble groups is crucial for the prediction of the bubble size distribution in bubble columns when adopting the population balance model (PBM) to estimate the heat and mass transfer across the interfaces between bubbles and carrier liquid. The majority of breakage kernels that are currently adopted focus on the shear turbulence in the liquid phase and model the kinetic energy contained in the arrival eddies that hit the bubbles by using the classical single-phase turbulence Kolmogorov −5/3 scaling law. In bubble columns, eddies that collide with bubbles and cause the bubble breakage are mainly generated by bubble-induced turbulence (BIT). The present work focuses on the influence ofκ−3scaling of the bubble-induced turbulence energy spectrum on the bubble breakage due to the eddy-bubble collision in bubble columns. A modified breakage model accounting for the bubble-induced turbulence is proposed. The proposed breakage model considers the mean turbulent velocity of eddies under the influence of bubble-induced turbulence and the characteristic wavenumber/length scale that corresponds to BIT. A comparison of the simulation results with the experimental data clearly demonstrate that the modified breakage model appropriately describes the bubble breakage events occurring under the influence of bubble-induced turbulence in bubble columns. It is also shown that the interaction of bubbles with the bubble-induced turbulence eddies has an impact on prediction of the mass transfer in bubble column flows.