Multiscale Modeling of Drying as a Powerful Extension of the Macroscopic Approach: Application to Solid Wood and Biomass Processing

This article is devoted to multiscale approaches of heat and mass transfer in porous media, with particular reference to drying. The macroscopic formulation of coupled heat and mass transfer has been widely used in the past two decades to model and simulate the drying of one single piece of product, including in the case of internal vaporization. However, more often than expected, the macroscopic approach fails. Several examples are proposed here, in which these limitations are addressed by accounting for several scales simultaneously. Different formulations are briefly presented to allow two spatial scales to be considered concurrently. Then, some simulations of multiscale transfer configurations are proposed: drying of a heterogeneous porous medium, drying of a stack of timber, convective drying of a thick bed of particles, and storage of a bed of particles.