Principal characteristics of a bubble formation on a horizontal downward facing surface
Principal characteristics of a bubble formation on a horizontal downward facing surface
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水平向下表面上气泡形成的主要特征
DOI：
10.1016/j.colsurfa.2012.07.007
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
William Yang
中科院分区：
文献类型：
--
作者：
S. Das;Y. Morsi;G. Brooks;John J. J. Chen;William Yang
气泡在下表面上的形成以及由于浮力和表面张力而导致的形状变化是重要的基本现象，其有助于理解许多气液系统，特别是Hall-Héroult铝电解槽中涉及的流体动力学。本文采用冷态模型和数值模拟方法研究了注气速率和喷孔直径对单气泡形成的影响，该气泡是由水平浸没在水和十二烷基硫酸钠（SDS）水溶液中的平板上的喷孔产生的。在实验部分的研究中，高速摄像机被用来记录气泡的运动，然后使用相场法进行数值分析。结果表明，当气泡在下向浸没的水平板上生长时，较低的表面张力对气泡的平衡厚度有影响。当表面张力从水降低到SDS水溶液0.036N/m时，气泡厚度可减少8-10%。此外，气泡的厚度被发现是一个函数的注射速率和液体的表面张力，而在初始形成过程中的气泡的形状变化被发现是在周围的流体中的诱导流的主要原因。预测的数值结果的变化在气泡的厚度和它的纵横比（AR）在初始气泡的发展与我们的实验结果进行了验证。气泡的厚度显示出良好的协议与预测数据，而长径比显示出类似的趋势，在初始增长。
The formation of gas bubbles on downward facing surface and the variation in their shape due to buoyancy and surface tension forces are important fundamental phenomena that contribute significantly to the understanding of the hydrodynamics involve in many gas–liquid systems and particularly in Hall–Héroult aluminium cell. In this paper a cold model and numerical simulation study was carried out to determine the effect of gas injection rates and orifice diameters on the formation of a single bubble arising from an orifice placed on a flat plate submerged horizontally in water and aqueous sodium dodecyl sulphate (SDS) respectively. In the experimental part of the study, high speed camera was used to record the bubble movements followed by a numerical analysis using the phase-field method. The findings indicated that lower surface tension has an influence on equilibrium thickness of the bubble when it grows on a downward facing submerged horizontal plate. The thickness of the bubble can be decreased by 8–10% for a decrease in surface tension from water to aqueous SDS by 0.036N/m. Moreover, the thickness of the bubble was found to be a function of the injection rate and the surface tension of the liquid, whereas the shape change of the bubble during the initial formation was found to be the main cause for the induced flow in the surrounding fluid. The predicted numerical results of the changes in the bubble thickness and its aspect ratios (AR) during initial bubble development were validated against our experimental results. The thickness of the bubble shows a good agreement with the predicted data while the aspect ratio shows similar trend during initial growth.