Theoretical and experimental study of heat and mass transfer mechanism during convective drying of multi-layered porous packed 1^

摘要

In this paper, the experimental validation of a combined mass and thermal model for a convective drying of multi-layered packed beds composed of glass beads, water and air is presented. The effects of the drying time, particle size and the layered structure on the overall drying kinetics are clarified in detail. Based on a completed model combining the temperature, total pressure and moisture equations, the results show that the convective drying kinetics strongly depend on the particle size as well as hydrodynamic properties and layered structure, considering the interference between capillary flow and vapor diffusion in the multi-layered porous packed bed. The predicted results are in a good agreement with the experimental results.