2024/07/31 by Simon Hartmann, Hartmann, Simon, Uwe Thiele +1 · 2 citations
Engineering · #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Fluid Dynamics and Heat Transfer
paper · pdf · doi:10.48550/arxiv.2408.00179
openalex publication_date 2024/07/31 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We present a mesoscopic hydrodynamic model for a spreading drop of volatile partially wetting liquid on a solid porous layer of small thickness. Thereby, evaporation takes place under strong confinement, i.e., we consider a drop that spreads on one of two parallel plates that form a narrow gap. Our gradient dynamics model describes the coupled dynamics of the vertically averaged vapor density profile, the drop height profile, and the vertically averaged saturation profile in the porous layer. The underlying free energy incorporates saturation-dependent wettability, capillarity of the drop and within the porous layer, air and vapor entropy, and an entropic contribution relevant close to complete filling of the porous layer. After developing the model we discuss the resulting sorption isotherm and illustrate typical drop spreading and imbibition behavior including the formation of a saturation halo within the porous substrate.