Shapes and Rise Velocities of Single Bubbles in a Confined Annular Channel: Experiments and Numerical Simulations
Shapes and Rise Velocities of Single Bubbles in a Confined Annular Channel: Experiments and Numerical Simulations
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DOI：
10.3390/fluids6120437
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发表时间：
2021-12
期刊：
影响因子：
1.9
通讯作者：
A. Cioncolini;M. Magnini
中科院分区：
文献类型：
--
作者：
A. Cioncolini;M. Magnini
采用实验和数值模拟相结合的方法，研究了单个气泡在环形通道内滞水中上升的速度和速度。实验中使用了快速视频成像和图像处理，而数值模拟则使用流体体积法和开源软件包OpenFOAM进行。环形通道的限制不影响气泡的定性行为，其表现出类似于在通过无限制液体上升的气泡中观察到的摆动上升动态。约束的形状和上升速度的影响是显而易见的，气泡变形较小，上升速度较慢，通过无约束液体上升的气泡相比。目前的数据和数值模拟，以及从文献中收集的数据在这里使用，表明单个气泡的大小，形状和上升速度是紧密联系在一起的，和预测方法，未能认识到这一点表现不佳。这项研究和文献中记录的有限证据表明，在复杂形状的非圆形通道中观察到的约束效应比在圆形管道中观察到的约束效应更复杂，并且更不容易理解。
Shapes and rise velocities of single air bubbles rising through stagnant water confined inside an annular channel were investigated by means of experiments and numerical simulations. Fast video imaging and image processing were used for the experiments, whilst the numerical simulations were carried out using the volume of fluid method and the open-source package OpenFOAM. The confinement of the annular channel did not affect the qualitative behavior of the bubbles, which exhibited a wobbling rise dynamic similar to that observed in bubbles rising through unconfined liquids. The effect of the confinement on the shape and rise velocity was evident; the bubbles were less deformed and rose slower in comparison with bubbles rising through unconfined liquids. The present data and numerical simulations, as well as the data collected from the literature for use here, indicate that the size, shape, and rise velocity of single bubbles are closely linked together, and prediction methods that fail to recognize this perform poorly. This study and the limited evidence documented in the literature indicate that the confinement effects observed in non-circular channels of complex shape are more complicated than those observed with circular tubes, and much less well understood.