Novel CFD-DEM Model for Spouted Bed Drying Incorporating Intraparticle Heat and Mass Diffusion

Abstract

In the final phase of particle drying in a spouted bed, the drying rate is governed by intraparticle heat and mass diffusion. Coupled computational fluid dynamics and the discrete element method (CFD-DEM) have proven to be suitable tools for modeling gas–solid in a spouted bed. However, existing CFD-DEM models are primarily employed to calculate the interphase heat and mass transfer rates based on an assumption of uniform intraparticle temperature and moisture distributions. Alternatively, some models take into account only the evaporation on the surface of the particles. As a result, these models may not reasonably represent the final phase of particle drying. This study introduces a novel CFD-DEM model for spouted bed drying that incorporates intraparticle heat and mass diffusion. The model combines the CFD-DEM governing equations with two one-dimensional intraparticle heat and mass diffusion equations. Benchmark cases using a spouted bed are presented to demonstrate the feasibility of the proposed model. The results indicate that the CFD-DEM model effectively reproduces the rational heat and mass transfer laws of the spouted bed particle drying process characterized by an overall decline in transfer rates. Furthermore, the model provides valuable insights into the temperature and moisture distributions within the particles. The proposed model exhibits great potential for extension to real-world industrial applications, encompassing complex heat and mass diffusion phenomena as well as coupling characteristics.

Comprehensive CFD-TFM Simulation of Drying in Spouted Beds with Draft Tubes

“…Che et al demonstrated that during the final phase of particle drying in a spouted bed, intraparticle heat and mass diffusion primarily control the drying rate. They employed a coupled CFD and discrete element method (DEM) (CFD–DEM) to model the gas–solid interactions within a spouted bed.…”

Multiphase Transportation, Conversion, & Utilization of Energy in Chemical Engineering: A Special Issue for MTCUE-2022

“…Experimental results were given for fitting the axial sinusoidal distribution during expansion, where the values of adjusted R 2 ranged from 0.72 to 0.95. Che et al 15 introduced a novel CFD-DEM model for spouted bed drying that combines intraparticle heat and mass diffusion. It was shown that the CFD-DEM model effectively reproduced the reasonable heat and mass transfer laws of spouted-bed particle drying process characterized by an overall decrease in transfer rates.…”