A modified drag model for the fluidization of nano-modulated Group C particles--颗粒学报PARTICUOLOGY

a School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
b Department of Chemical and Biochemical Engineering, The University of Western Ontario, Canada
c Eastern Institute of Technology, Ningbo, China

10.1016/j.partic.2024.10.007

Volume 96, January 2025, Pages 14-25

Received 25 May 2024, Revised 10 September 2024, Accepted 3 October 2024, Available online 24 October 2024, Version of Record 14 November 2024.

E-mail: wjingtao928@tju.edu.cn

Highlights

• A modified drag model is proposed for simulating fluidization of nano-modulated Group C powders.

• The results obtained utilizing modified drag model are close to those of other widely used drag models.

• Pseudo agglomerate sizes of Group C⁺ particles are calculated based on experimental results.

• Agglomeration ratio d_pa/d_p is approximately linearly related to the Ar^−1/3 of the particles.

• For Group C⁺ particles, the calculated n value is smaller than n value in other widely used drag models.

Abstract

Geldart Group C powders are inherently cohesive due to the strong interparticle forces, leading to severe agglomeration and poor fluidization capability. In this study, fluidization of nano-modulated Group C particles was investigated numerically. These particles, also known as Group C⁺ particles, were obtained through the nanoparticle modulation technique, with which a small fraction of nanoparticles were vigorously mixed with Group C particles so that they are adhered to the surface of the much larger Group C particles. After modification, the cohesiveness of Group C⁺ particle was significantly weakened, and therefore these particles could exhibit much better fluidization quality. However, the still existing cohesion resulted in the formation of small agglomerates within the system. To understand the internal agglomeration mechanisms of Group C⁺ particles and their impact on fluidization behaviors, a new drag model was proposed based on experimental results and the postulation of particle agglomeration. The numerical results of the cases employing the new drag model agreed well with the experimental data in terms of total and dense phase expansion. These findings revealed the drag mechanism associated with modified Group C particles, contributing to the understanding of ultrafine particle fluidization.

Graphical abstract

Keywords

Fluidization; Nano-modulated Group C particles; Drag model; Agglomeration

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