Key structural characteristics of porous layers in diffusion modelling: A study on polydispersity, shape, and hierarchy

In this study, we explored various open-source models for generating porous media. These models enabled us to examine different types of porous beds, including layers of polydisperse spheres with various size distributions, layers of porous aggregates – either fragments of parent porous layers or those formed during the agglomeration of polydisperse spheres – and layers of non-spherical particles with both regular and random shapes. Through extensive simulations, we derived estimates for the averaged structural characteristics of the model layers. These estimates will be utilized in macroscopic models to study heat diffusion and the sublimation of products in the near-surface layer of a cometary nucleus. Our findings revealed significant differences between the obtained estimates and those previously made for layers of monodisperse spheres, underscoring the importance of this research. We also compared numerical results with theoretical formulas for layers of monodisperse spheres.