Strain–Stress Formation During Stationary and Intermittent Drying of Deformable Media

The goal of this work is to study the effect of different drying conditions on the induced stresses within deformable media, the drying kinetics, and the energy consumption. A comparison between stationary and intermittent drying with periodically changing air temperature was performed. A theoretical formulation of the coupled heat, mass, and momentum transfers in saturated porous media was established. The model is based on the averaging theory. The thermo-hydro-mechanical coupling was closed using the effective stress theory of Terzaghi. In this approach, the viscoelastic behavior of the medium was considered. A bi-dimensional-shaped bentonite sample was used for numerical tests. The evolution of drying kinetics and stresses within the material during drying at constant and intermittent conditions was presented. It was observed that a non-stationary drying with smaller period applied at the end of the constant drying rate phase has the best effects on the product quality and energy gain without considerably extending the drying time.