Retrospect and Perspective of Micro-mixing Studies in Stirred Tanks

• Published in: Chinese journal of chemical engineering 2012-02, Vol.20 (1), p.178-190
• Main Author: 程景才 冯鑫 程荡 杨超
• Format: Article
• Language: English
• Subjects: Byproducts; Chemical engineering; Computational fluid dynamics; Mathematical models; micro-mixing; micro-mixing model; multiphase; Phases; Purification; stirred tank; Tanks; Turbulence; 实验技术; 展望; 微观混合; 拉格朗日; 搅拌槽; 欧拉模型; 混合问题; 计算流体动力学
• ISSN: 1004-9541; 2210-321X
• DOI: 10.1016/s1004-9541(12)60378-4

Mixing problems are most likely encountered and sometimes can be severe in scaling-up projects. Micro-mixing is an important aspect for fast or quasi-instantaneous reactions. Poor micro-mixing might produce more undesired by-products, leading to higher purification costs. This paper gives an extensive review and analysis of micro-mixing studies in single- and multi phase stirred tanks. The relevant experiment techniques, micro-mixing models and nurherical approaches are critically reviewed and analyzed with remarks and perspectives. The reported studies on two-phase micro-mixing experiments and on the impact of the presence of the dispersed phases on turbulence have been limited to a narrow range of conditions. More importantly, disparities widely exist among different reports. Both Lagrangian and Eulerian models are based on oversimplified assumptions, which may lead to uncertainties or even unrealistic results. A heuristic model, which is from the perspective of CFD （computational fluid dynamics） and can cover the whole spectrum of scales and also focus on every subrocess, is desired in the future.