Heat and mass transfer performance of non-spherical wet particles in a fluidized bed dryer

Abstract

In fluidized bed dryers, wet particle shape greatly influences mass and heat transfer performance, which is a key for the regulation of drying systems. In this work, mass and heat transfer behaviors of ellipsoid wet particles in a fluidized bed dryer is investigated by means of the computational fluid dynamics-discrete element method (CFD-DEM), where the heat transfer mechanisms caused by the contact, convection and liquid bridge are analyzed. Meanwhile, the liquid transfer during the drying and collision process of non-spherical wet particles is considered. The results reveal that the reduction of liquid content weakens the heat flow between particles. In contrast to spherical particles, the agglomeration of non-spherical particles is more obvious during the drying process, resulting in a lower drying rate. As the drying proceeds, the correlation between drying rate and drag force appears a power exponential trend.