CFD-DEM modeling and experimental validation of fluidized bed drying using Reaction Engineering Approach

Fluidized bed drying is an effective technique for drying particulate materials and is widely applied in post-harvest processing of agricultural products as well as in industrial applications. This study develops a numerical drying model based on a coupled Computational Fluid Dynamics (CFD) and Discrete Element Method (DEM) approach to describe heat and mass transfer processes in a gas-solid system. Moisture evaporation is modeled using the Reaction Engineering Approach (REA). The model is presented in detail and evaluated through rigorous comparison of simulation results with experimental data for \(γ\) -alumina particles reported in the literature. Rather than relying on simplified continuum approximations, this framework achieves direct particle-scale resolution for a fully resolved system comprising thousands of individual particles. The results demonstrate that the predicted drying rate curves are in good agreement with the experimental data. Additionally, the temperature and humidity fields of the gas phase are analyzed to examine the underlying heat and mass transfer mechanisms in the fluidized bed. The quality of the dried product is systematically evaluated through the spatial moisture distribution of the particles. Furthermore, a polydisperse (multi-size) particle system model is established to investigate the inter-particle distributions of physical parameters in a heterogeneous system. The results indicate that this particle-scale model offers strong potential for application in the optimization, design, and process control of industrial fluidized bed drying.