Non-isothermal drying of thin porous disks

Thin porous media (TPM) are porous layers that are characterized by a small thickness that can be orders of magnitude smaller than the lateral dimensions. Examples are papers, coatings, membranes, self-assembled layers, self-disposing layers, such as salt crusts or filter cakes and biofilms, or also the fibrous gas diffusion layer (GDL) of a PEM fuel cell. TPM must be distinguished from the thick porous media because of the lack of length scale separation due to the very small expansion of the porous medium over often only a few pore rows in the through-plane direction and because the transport properties can depend on the thickness of the TPM. Thus, TPM represent a distinct class of porous media for which traditional continuum models are not adapted. For several reasons pore network models offer several advantages that allow for a numerical investigation of the transport processes in TPM. Surprisingly, although a drying step is almost always present in the manufacturing, the formation or the use of TPM, drying of TPM has received relatively little attention. For this reason, we investigate a few aspects of drying in a thin system from 3D pore network simulation, both in isothermal and non-isothermal situations