(746a) DEM-CFD Simulation of the Drying of Heterogenous Particles in a Wall-Heated Rotated Drum

The drying process in gas-solid flows involves complex mass (liquid transfer between particles, liquid evaporation to the gas phase and mass transfer in the gas phase), momentum (solid contacts, gas flow, inter-phase momentum transfer) and heat (heat transfer on solid contacts, convective heat transfer in gas phase, inter-phase heat transfer) transfer. These coupled transport mechanisms make analytical approaches to this problem daunting, nevertheless, by incorporating mass transfer (liquid evaporation from particle surface to gas phase and mass transfer in the gas phase) modeling into an our existing gas-solid DEM-based heat transfer code, the drying process is successfully simulated. Here we examine the prototype case of a wall-heated rotary kiln dryer with non-porous particles. Our results show a constant rate drying period as is typically observed experimentally. Results are reported for both mono-disperse and bi-disperse cases as well as for materials with high and low thermal diffusivities. Dimensionless parameters are used to rationalize our varying results.