Abstract

Bubble plumes are often encountered in numerous industrial applications where the gas-liquid two phase interaction is used to promote the mixing of the liquid phase. The current work is focused on the investigation of the mixing behavior of bubble plumes produced by a circular source in confined two-layer stratified fluids. In analogy to the study of linear stratification, two non-dimensional parameters P_{N_EQ} (=\( {N}_{EQ}^3{H}^4/{Q}_Bg \), where N_EQ is the equivalent linear buoyancy frequency, H is the water depth, Q_B is the gas flow rate, and g is the gravity acceleration) and M_H (=\( {Q}_Bg/\left(4\pi {\alpha}^2{u}_s^3H\right) \), where α is the entrainment coefficient and u_s is the slip velocity) are selected to investigate the flow patterns and mixing efficiency in two-layer stratified fluids. The equivalent linear buoyancy frequency N_EQ of the two-layer stratification is proposed to calculate the non-dimensional parameter P_{N_EQ}. The flow structure of a bubble plume in two-layer stratified fluids is introduced in detail. The correlations of the non-dimensional parameters with the bubble plume properties, such as the flow patterns, initial destratification height and mixing efficiency, are obtained. The results show that correlations with the non-dimensional parameter P_{N_EQ} can be successfully used to predict the bubble plume behavior in a confined two-layer stratified fluids.

中文翻译：

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密闭的两层分层液体通过气泡羽流混合

摘要

气泡羽流在许多工业应用中经常遇到，在该应用中，气液两相相互作用被用来促进液相的混合。当前的工作集中在研究由圆形源在受限的两层分层流体中产生的气泡羽流的混合行为。类似于线性分层的研究，两个无量纲参数P _{N_EQ}（= \（{N} _ {EQ} ^ 3 {H} ^ 4 / {Q} _Bg \），其中N _EQ是等效线性浮力频率，H是水深，Q _B是气体流速，g是重力加速度）和M _H（=选择\（{Q} _Bg / \ left（4 \ pi {\ alpha} ^ 2 {u} _s ^ 3H \ right）\），其中α是夹带系数， u _s是滑移速度）以研究两层分层流体的流动模式和混合效率。提出了两层分层的等效线性浮力频率N _EQ来计算无量纲参数P _{N_EQ}。详细介绍了气泡羽流在两层分层流体中的流动结构。获得了无量纲参数与气泡羽流特性的相关性，例如流动模式，初始脱层高度和混合效率。结果表明，与无量纲参数P _{N_EQ的}相关性可以成功地用于预测密闭两层分层流体中的气泡羽_流行为。