Novel CFD-DEM approach for analyzing spherical and non-spherical shape particles in spouted fluidized bed

Abstract

The spouted fluidized bed process is a multiphase heat and mass transfer flow. The process requires effective solid-gas and solid-solid interaction. Various numerical models have been developed to understand and optimize these interactions. However, most of these models have used spherical particle definition, whereas the actual particles are non-spherical. Here we present coupled Computational Fluid Dynamics(CFD) and Discrete Element Method(DEM) based model to analyze the fluidized bed process for non-spherical particles (Faceted cylinder). The model results are validated with experimental results for spherical particles. The model is further used to understand mixing during the process as a function of non-spherical particle geometry. Aspect ratio and corner count were the geometrical input parameters for faceted cylinder-shaped particles. Transient plots for bubble diameter and bed height for spouted fluidized beds were created for all cases. The bubble diameter and bed height values were much lower for faceted cylinder particles than for spherical particles. For non-spherical particles, the increased number of corners was a crucial factor that brought the outcomes closer to those of spherical-shaped particles. The aspect ratio values increased, and the bubble diameter shrank as a result of more resistance to particle movement. The results would be of great use to correctly simulate non- spherical particles based fluidized bed process and optimize various process parameters.

GRAPHICAL ABSTRACT

HIGHLIGHTS

1. The coupled CFD-DEM method was used to analyze the hydrodynamics of spouted fluidized beds for spherical and faceted cylinder particles by plotting bubble diameter and bed height

2. Analysis showed that non-sphericity brought resistance to the movement of particles inside the chamber, affecting efficient mixing between phases.

3. The increased number of corners for non-spherical particles became the dominating parameter compared to aspect ratio for resembling results of fluidized beds closer to spherical-shaped particles.

4. Post-processing of the results by division tagging showed that non-spherical particles have less tendency to mix than spherical particles.

Keywords:

• CFD-DEM
• fluidization
• non-spherical
• faceted cylinder
• Eulerian Langrangian approach

Acknowledgments

The authors acknowledge the financial support from Ministry of Mines (project number Met4/6/2022).

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article.