CFD-PBM approach with modified drag model for the gas-liquid flow in a bubble column
CFD-PBM approach with modified drag model for the gas-liquid flow in a bubble column
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CFD-PBM 方法，采用修改后的气泡塔中气液流动阻力模型
DOI：
10.1016/j.cherd.2016.06.014
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发表时间：
2016-08-01
影响因子：
3.9
通讯作者：
Luo, Zheng-Hong
中科院分区：
文献类型：
--
作者：
Liang, Xiao-Fei;Pan, Hui;Luo, Zheng-Hong
本文采用Euler-Euler方法结合粒子数平衡模型（PBM）对圆柱形鼓泡塔进行了数值模拟。首先，三个阻力模型和相应的修正模型与尾流加速度被纳入耦合方法，以评估这些阻力模型的有效性。采用不同的阻力方程模拟的时均局部气含率和归一化轴向液体速度与实验数据进行了比较，结果表明，只有考虑尾流加速度的PBM定制阻力模型（参见，校正因子的应用）可以再现所测量的流场数据。随后，在不同的表观气速和气体分布器的有效阻力模型的耦合方法的适用性进一步评估。在高气速下，模拟结果与实验数据雅阁较好。然而，该模型大大低估了径向局部气含率和总气含率在低气体流量。此外，模拟结果还表明，开口面积和孔板的几何形状对鼓泡塔内的总通气量有重要影响，三环气体分布器比多孔气体分布器能产生更均匀的局部气含率和归一化液速径向分布，从而导致鼓泡塔内混合效率较差。(C)2016化学工程师学会。Elsevier B. V.出版，保留所有权利。
In this work, numerical simulations of cylindrical bubble column are performed using the Euler-Euler approach incorporated with a population balance model (PBM). First, three drag models and their corresponding modified models with the wake acceleration are incorporated into the coupled approach in order to evaluate the effectiveness of these drag models. The simulated time-averaged local gas holdups and normalized axial liquid velocities using different drag equations are compared with the experimental data, showing that only the PBM-customized drag model with the wake acceleration (cf., the application of a correction factor) can reproduce the measured flow field data. Subsequently, the applicability of the coupled approach with the effective drag model is further evaluated at various superficial gas velocities and gas distributors. The simulated results accord well with the experimental data at high gas velocities. However, the model greatly underestimates the radial local gas holdup and the total gas holdup at low gas flow rates. Additionally, the simulated results demonstrate that the opening area and orifice geometry play a significant role in total aeration and the triple-ring gas distributor produces more uniform radial profiles of local gas holdup and normalized liquid velocity than the multi-orifice one, thus leading to poor mixing efficiency in the bubble column. (C) 2016 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.