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

In the final phase of particle drying in a spouted bed,the dryingrate is governed by intraparticle heat and mass diffusion. Coupledcomputational fluid dynamics and the discrete element method (CFD-DEM)have proven to be suitable tools for modeling gas-solid ina spouted bed. However, existing CFD-DEM models are primarily employedto calculate the interphase heat and mass transfer rates based onan assumption of uniform intraparticle temperature and moisture distributions.Alternatively, some models take into account only the evaporationon the surface of the particles. As a result, these models may notreasonably represent the final phase of particle drying. This studyintroduces a novel CFD-DEM model for spouted bed drying that incorporatesintraparticle heat and mass diffusion. The model combines the CFD-DEMgoverning equations with two one-dimensional intraparticle heat andmass diffusion equations. Benchmark cases using a spouted bed arepresented to demonstrate the feasibility of the proposed model. Theresults indicate that the CFD-DEM model effectively reproduces therational heat and mass transfer laws of the spouted bed particle dryingprocess characterized by an overall decline in transfer rates. Furthermore,the model provides valuable insights into the temperature and moisturedistributions within the particles. The proposed model exhibits greatpotential for extension to real-world industrial applications, encompassingcomplex heat and mass diffusion phenomena as well as coupling characteristics.

Automated summary

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 and 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.