Numerical investigation of formation and dissolution of CO2 bubbles within silicone oil in a cross-junction microchannel
Numerical investigation of formation and dissolution of CO2 bubbles within silicone oil in a cross-junction microchannel
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DOI：
10.1007/s10404-017-2011-7
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发表时间：
2017-11
影响因子：
2.8
通讯作者：
Gim Yau Soh;G. Yeoh;V. Timchenko
中科院分区：
文献类型：
--
作者：
Gim Yau Soh;G. Yeoh;V. Timchenko
本文对交叉点微通道中硅油中CO2气泡的形成和溶解过程进行了数值研究。采用基于流体体积法的多相多组分耦合计算流体力学模型，能够很好地模拟多相气泡的形成、溶解传质和溶解CO2的跟踪等物理过程。计算模型首先与实验结果进行了验证，取得了较好的一致性。然后，利用该模型研究了存在溶解作用的交叉口气泡的形成过程，以及气泡沿下游通道输送时的演化过程。结果表明，在气泡形成过程中，由于流向该区域的硅油很少，在交叉结壁周围有较高浓度的CO2溶质。当二氧化碳气泡向下游流动时，二氧化碳溶质的传输很大程度上是由气泡附近硅油的局部流动电流驱动的。还进行了广泛的参数研究，考察了改变表面张力、扩散系数和流速的影响。结果表明，初始CO2气泡长度和气泡形成周期受流量的影响最大，而传质受扩散系数的影响最大。
In this paper, a numerical investigation is conducted to study the formation and dissolution process of CO2bubbles within silicone oil in a cross-junction microchannel. A coupled multiphase–multicomponent computational fluid dynamics model based on the volume-of-fluid method is used, which is able to capture the physics of the multiphase bubble formation, dissolution mass transfer, and the tracking of the dissolved CO2species. The computational model is firstly validated with experimental results where good agreement is attained. Next, the model is used to investigate the bubble formation process at the cross-junction in the presence of dissolution and also the bubble evolution as it is transported along the downstream channel. It is revealed that during bubble formation, there is a high concentration of CO2solute around the cross-junction walls, as silicone oil flow to this region is minimal. As the CO2bubble travels downstream, the transport of the CO2solute is largely driven by the local flow currents of the silicone oil within the vicinity of the bubble. An extensive parametric study is also conducted, looking at the effects of varying the surface tension, diffusion coefficient and flow rates. The results demonstrate that the initial CO2bubble length and period of bubble formation are most affected by the flow rate, while the mass transfer is most strongly governed by the diffusion coefficient.