Design of Nanoparticle Dispersion Process in Stirred Media Mill Using DEM–LES Coupling Method

JOURNAL OF CHEMICAL ENGINEERING OF JAPAN

Yoshiyuki Shirakawa²  Jusuke Hidaka²  Daisuke Nishiura¹  Ryoko Asahi²  Atsuko Shimosaka² 

[1] Institute for Research on Earth Evolution, Japan Agency for Marin-Earth Science and Technology;Department of Chemical Engineering and Materials Science, Faculty of Science and Engineering, Doshisha University

关键词: Aggregates;    Fluid Shear Power;    Collision Power;    Friction Power;    Scaling Law;   

DOI  :  10.1252/jcej.12we022

来源: Maruzen Company Ltd

【 摘 要 】

References(14)Cited-By(1)A nanoparticle dispersion process was designed on the basis of a simulation-based in-depth evaluation of the bead–fluid interactions in a stirred media mill. Volume-averaged four-way coupling equations were used to simulate the bead motion and turbulent flow. A distinct element method (DEM) was studying for bead motion and a large eddy simulation (LES) was used for investigation turbulence flow. Methods for calculating the power of the fluid shear, bead collision, and friction are presented in this paper. A high power area that developed in the mill was visually represented and quantified. In addition, the effect of the fluid shear, bead collision, and friction power on the dispersion of aggregates was evaluated in detail by varying the operational parameters. Under the conditions that promote dispersion of the aggregates (high bead filling ratio, high stirring rate, and small bead diameter), the fluid shear power was the only force generated in the mill that consistently increased. The frequency of bead–bead contact, which is thought to be an important factor influencing dispersion, was also calculated. This parameter remained unchanged when the stirring rate was increased; in contrast, the frequency of bead–bead contact increased for a high bead filling ratio and smaller bead diameter. The correlation of the average size of the aggregated particles attained in the dispersion experiment after 30 min with each factor (fluid shear, bead collision, and friction) and with the frequency of bead–bead contact was examined, and strong correlation of the average size of the aggregated particles with the fluid shear power and the frequency of bead–bead contact was observed. Therefore, for effective dispersion of the aggregates into the primary particle size, an increase in both the fluid shear power and the frequency of bead–bead contact is critical. In addition, these correlations facilitated the optimum design of a dispersion process in the wet stirred media mill.

【 授权许可】

Unknown