Speaker
Description
We introduce an isothermal phase-field model for the coupled evaporation and crystallization of an aerosol droplet containing dissolved solutes: as the liquid evaporates, the dissolved solute, for example salt, becomes increasingly concentrated and, once it exceeds a saturation threshold, precipitates by forming a crystalline phase.
The model is described by a three-phase (liquid, crystalline, vapor) Cahn-Hilliard/Allen-Cahn system. The evolution of the phases is coupled with a diffusion equation for the solute concentration.
A central modeling choice is to consider the dissolved or crystalline solute content as a conserved order parameter while allowing the liquid to become supersaturated with solute. The saturation concentration is imposed softly, namely, supersaturation is permitted, but carries an energetic cost that increases smoothly beyond the saturation threshold.
We derive and study such a model based on a thermodynamic structure.