Modeling of Drying of Droplets Containing Passive Solid Particles in Airflow

<p>Understanding the drying of droplets is of interest for processes such as spray drying where particulate materials are produced by  evaporating moisture. This work focuses on the multi-phase modeling of drying a droplet containing passive insoluble solid particles. Using a volume-of-fluid framework coupled with a passive Lagrangian phase, we investigated the effects of airflow, phase properties (e.g., viscosity and density of each phase), surface tension, internal circulation, and nonuniform evaporation for various conditions. Unlike the traditional one-dimensional modeling approach, our multi-dimensional model can capture the generation of internal flow patterns due to shear flow and the accumulation of solid particles on the surface of the drying droplet. Our results show that the surface tension effect is more pronounced at larger droplet diameters and low airflow velocities. In addition, solids agglomeration is highly influenced by airflow and asymmetrical. In addition, the surface tension could be easily modified to be a function of other variables such as surfactant or solids concentration. Future work includes coupling the solids to the fluid phase.</p>