Flow visualization by PLIF technique and numerical modeling of mixing enhancement in stirred tank under electric fields

被引：0
|
作者：
Sun J. [1 ]
Liu H. [1 ]
Wang J. [1 ]
He F. [1 ]
机构：
[1] School of Energy and Power Engineering, Jiangsu University, Zhenjiang
来源：
Huagong Jinzhan/Chemical Industry and Engineering Progress | 2021年 / 40卷 / 12期
关键词：
Computational fluid dynamics (CFD); Electro-hydro dynamics (EHD); Mixing; Planar laser induced fluorescence(PLIF);
D O I：
10.16085/j.issn.1000-6613.2021-1398
中图分类号：
学科分类号：
摘要：
In laminar mixing, the periodic perturbation of the impeller causes the enclosed and isolated annular flow field in the stirred tank. The isolated flow field seriously obstructs the effective exchange between the stirring medium and reduces the stirring efficiency. Therefore, an applied electric field was proposed in this paper to enhance the laminar mixing efficiency, and the electrohydrodynamic effect was employed to induce the polarization force of the mixed fluid. This effect changed the symmetrical structure of the flow field, and eliminated the isolated mixing regions. The real-time visualization of the flow field structure in the stirred tank was realized by using Planner laser induced fluorescence (PLIF) technology. The isolated flow region was identified and the percentage of the unmixed area was calculated in post-image processing by custom-made functions. The results showed that the mixing efficiency could be gradually increased to 98% under the electric field intensity of 1.5kV/cm. In addition, the simulation platform based on finite element method and concentration diffusion model was established. Through the simulation analysis, it was found that the secondary eddy appeared once the applied electric field intensity upon to 0.5kV/cm. The secondary eddy interacted with the radial mixing flow which diminished the isolated flow region. Under the condition of constant electric field strength, periodic electric field can further improve the mixing efficiency. Periodic electric field can make the mixing efficiency reach more than 98%, when electric field was at 1kV/cm. © 2021, Chemical Industry Press Co., Ltd. All right reserved.
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页码：6547 / 6556
页数：9
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