Enhanced transport in a porous medium due to dissolved salt

An experiment is presented showing enhanced water transport across a porous layer compared to pure water vapor diffusion. The enhanced transport is explained by the presence of brine in the layer and the dependence of the equilibrium vapor pressure with the dissolved salt concentration. The impact of the salt presence is further demonstrated by a comparison with the case of pure water. A significantly longer period of sustained evaporation is obtained in the presence of salt. The transport enhancement effect can last over long periods of time when the conditions are such that the porous layer reaches a dynamic equilibrium between condensation and evaporation. Also, the porous layer can adapt to changes in the boundary conditions via changes in the brine saturation and associated modifications in the salt concentration and the equilibrium vapor pressure. The transport enhancement effect is also illustrated in relation with the dynamics of salt crusts.8 MoreReceived 18 February 2022Accepted 24 May 2022DOI:https://doi.org/10.1103/PhysRevFluids.7.064304©2022 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasDisplacement of immiscible fluidsEvaporationFlows in porous mediaSurface tension effectsFluid Dynamics