Lattice Boltzmann simulations for micro -macro interactions during isothermal drying of bundle of capillaries

The fundamental understanding of the multiphase phenomena involved in drying of porous media is still a challenging task. Pore network models (PNMs) reveal the micro–macro interactions. However, PNMs have shortfalls in using true geometry, and in revealing capillary instabilities and film-effects. In this work, Shan Chen representation of Lattice Boltzmann Method (LBM) is applied to elucidate such complicated multiphase phenomena, i.e. micro-scale-dynamics evolution during drying. In a bundle of capillaries, liquid transport is explained with two pressure gradients. First, the pressure gradient between capillaries leading to capillary pumping, second, the pressure gradient within each capillary along the liquid–gas interface resulting in formation of hydraulic films. Transformation of hydraulic films to adsorbed films is revealed in irregular pore structures. Péclet number is employed to elucidate the effect of boundary layer thickness and temperature on drying kinetics. Characteristics of drying are re-established using the LBM for pore structures with bimodal size distribution. © 2020 Elsevier Ltd