Modelling moisture transport for a predominant water vapour diffusion in a partially saturated porous media

摘要

The aim of this paper is to establish by periodic homogenisation a macroscopic model for moisture transport in porous media for predominant water vapour diffusion, taking into account evaporation/condensation phenomena. The dimensional analysis of the continuity equations of moisture transport (and the associated boundary conditions) written at the pore scale lets appear dimensional numbers characterising the transfer phenomenon. The asymptotic expansion of these equations leads to a macroscopic homogenised equation governing the moisture transport. Moreover, we obtain an accurate definition of the homogenised diffusion tensor of moisture involving the geometry of the microstructure and known transport properties of the material. As an example, the diffusion of water vapour in a layered porous medium is considered and the homogenised diffusion tensor of water vapour is calculated.