Study of fluid cell coarsening for CFD-DEM simulations of polydisperse gas

Lei, H., Zhu, L., & Luo, Z. (2023). Study of fluid cell coarsening for CFD-DEM simulations of polydisperse gas–solid flows. Particuology, 73, 128-138. https://doi.org/10.1016/j.partic.2022.05.002

Study of fluid cell coarsening for CFD-DEM simulations of polydisperse gas–solid flows

He Lei, Litao Zhu, Zhenghong Luo ^*

Department of Chemical Engineering, School of Chemistry and Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai, 200240, China

10.1016/j.partic.2022.05.002

Volume 73, February 2023, Pages 128-138

Received 20 March 2022, Revised 29 April 2022, Accepted 3 May 2022, Available online 13 May 2022, Version of Record 27 May 2022.

E-mail: luozh@sjtu.edu.cn

Highlights

•Well-resolved CFD-DEM simulations of polydisperse gas–solid flows are performed.

•Significant impact of particle polydispersity on the gas–solid flow hydrodynamics.

•Quantifying the effect of PSD by ratio of particle size to Sauter mean diameter.

•Filtered drag models for coarse-grid CFD-DEM simulations are developed.

Abstract

Particle polydispersity is ubiquitous in industrial fluidized beds, which possesses a significant impact on hydrodynamics of gas–solid flow. Computational fluid dynamics-discrete element method (CFD-DEM) is promising to adequately simulate gas–solid flows with continuous particle size distribution (PSD) while it still suffers from high computational cost. Corresponding coarsening models are thereby desired. This work extends the coarse-grid model to polydisperse systems. Well-resolved simulations with different PSDs are processed through a filtering procedure to modify the gas–particle drag force in coarse-grid simulations. We reveal that the drag correction of individual particle exhibits a dependence on filtered solid volume fraction and filtered slip velocity for both monodisperse and polydisperse systems. Subsequently, the effect of particle size and surrounding PSD is quantified by the ratio of particle size to Sauter mean diameter. Drag correction models for systems with monodisperse and continuous PSD are developed. A priori analysis demonstrates that the developed models exhibit reliable prediction accuracy.

Graphical abstract

Keywords

Fluidized bed; CFD-DEM; Gas–solid flows; Fluid cell coarsening; Polydisperse drag force

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