Anisotropic Spreading of Bubbles on Superaerophilic Straight Trajectories beneath a Slide in Water
Anisotropic Spreading of Bubbles on Superaerophilic Straight Trajectories beneath a Slide in Water
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DOI：
10.3390/w12030798
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发表时间：
2020-03
期刊：
影响因子：
3.4
通讯作者：
Chengxu Tu;Qincan Yang;Yeyu Chen;Yuhang Ye;Yukun Wang;Pengfei Du;Sensen Yang;F. Bao;Zhaoqin Yin;R. Jiang;X.Q. Liang
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文献类型：
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作者：
Chengxu Tu;Qincan Yang;Yeyu Chen;Yuhang Ye;Yukun Wang;Pengfei Du;Sensen Yang;F. Bao;Zhaoqin Yin;R. Jiang;X.Q. Liang
虽然接触均匀超好氧表面的气泡由于其在各种工程设备（例如矿物浮选）中的应用潜力而引起关注，但是关于气泡如何在具有各向异性超好氧性的表面上扩散的机制知之甚少。为了揭开这个神秘的面纱，我们实验研究了气泡（直径为2毫米）在水中不同宽度（0.5 mm-5 mm）的超需氧直线轨迹（SALT）上的各向异性行为，使用高速阴影系统。1-3次反弹主要发生在泡沫在扩散之前接近SALT的时候。首先观察到气泡在各向异性扩展过程中会分裂成两个高度对称的子气泡，它们具有相反方向的相似的迁移速度。研究发现，窄SALT（W ≤ 2 mm，有两个亚区）和宽SALT（W ≥ 3 mm，有四个亚区）的各向异性扩展主要由两种机制引起。考虑SALT的表面张力效应和拉普拉斯压力的综合影响，建立了一个新的模型来预测接触尺寸r（t）作为时间的函数。该模型与实验结果吻合较好，再次证实了表面张力效应和拉普拉斯压力优于静水压力。
Although the bubble contacting a uniformly superaerophilic surface has caused concern due to its application potential in various engineering equipment, such as mineral flotation, very little is known about the mechanism of how the bubble spreads on a surface with anisotropic superaerophilicity. To unveil this mystery, we experimentally studied the anisotropic behavior of a bubble (2 mm in diameter) spreading on the superaerophilic straight trajectories (SALTs) of different widths (0.5 mm–5 mm) in water using a high-speed shadowgraphy system. The 1–3 bounces mostly happened as the bubble approached the SALTs before its spreading. It is first observed that the bubble would be split into two highly symmetrical sub-bubbles with similar migration velocity in opposite directions during the anisotropic spreading. Two essential mechanisms are found to be responsible for the anisotropic spreading on the narrow SALTs (W ≤ 2 mm with two subregimes) and the wide SALTs (W ≥ 3 mm with four subregimes). Considering the combined effect of the surface tension effect of SALT and Laplace pressure, a novel model has been developed to predict the contact size r(t) as a function of time. The nice agreement between this model and our experiments reconfirms that the surface tension effect and Laplace pressure prevail over the hydrostatic pressure.