Modeling mass transfer processes in multicomponent capillary-porous bodies under mixed boundary conditions

Abstract

In this study, we present a physicomathematical model for convective drying of a multicomponent body of the capillary-porous structure, considering moisture transfer dynamics at both macro and micro levels. Recognizing the impact of the material's local structure on drying processes, particularly in phase transformations, the model integrates the continuum-thermodynamic approach pioneered by Ya. Burak, Ye. Chaplya, and B. Gayvas. This approach addresses the interrelated mechanical, thermal, and diffusion processes occurring in heterogeneous, nonequilibrium systems, where local thermodynamic equilibrium assumptions allow equilibrium state descriptions by conjugate physical parameters. The unique dual-level approach captures moisture exchange between an individual grain and the grain bed, enabling realistic simulations of the drying process by directly accounting for phase transformations and material structure influences. The presented methodology allows simultaneous solving of mass transfer equations for the grain bed and individual grains, supported by numerical experimentation. The results reveal distinct moisture distribution patterns across the grain bed and within individual grains, with variations influenced by drying agent velocity. The novelty of this approach lies in its simultaneous treatment of grain-scale and bed-scale moisture transfer, providing a detailed perspective on moisture dynamics. This model has potential applications in optimizing industrial drying processes for capillary-porous materials, enhancing efficiency and cost-effectiveness.