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CFD Prediction of the Critical Agitation Speed for Complete Dispersion in Liquid-Liquid Stirred Reactors

✍ Scribed by D. Cheng; J. Cheng; Y. Yong; C. Yang; Z.-S. Mao


Publisher
John Wiley and Sons
Year
2011
Tongue
English
Weight
966 KB
Volume
34
Category
Article
ISSN
0930-7516

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✦ Synopsis


Abstract

A computational fluid dynamics (CFD) model is adopted to simulate the turbulent immiscible liquid‐liquid flow in a stirred vessel based on a two‐fluid model with a k‐ϵ‐A~P~ turbulence model. An improved inner‐outer iterative procedure is adopted to deal with the impeller rotation in a fully baffled stirred tank. Different drag formulations are examined, and the effect of the droplet size on both the dispersed phase holdup distribution and the velocity field is analyzed. Two different numerical criteria are tested for determining the critical impeller speed for complete dispersion. The simulated critical impeller speeds are generally in good agreement with the correlations in the literature when the fixed droplet size is properly selected. This demonstrates that the modeling approach and the numerical criteria proposed in this work are promising for predicting the dispersion characteristics in liquid‐liquid stirred tanks.