Numerical simulations and experimental verifications at micro-, meso-, and macroscales of droplet evaporation: A comprehensive review with special focus on saline droplets

Evaporation of saline droplets significantly impacts industrial processes such as water and gas treatment. Simulations, with advantages in describing temperature, concentration, and velocity distribution inside the droplet, receive increasing attentions. This paper summarized research on numerical simulations of droplet evaporation at micro-, meso-, and macroscales, emphasizing saline or multicomponent droplets. Accurate description of physics at phase interfaces and within proves to be critical for modeling. While recent studies have investigated on interface motion and temperature distribution, the coupling effect of internal concentration and flow distribution is still rarely considered. Among numerical methods, the lattice Boltzmann method is suitable for droplet scale due to its ability to handle non-continuum behavior. Bridging multiscale models remains a challenge, particularly in describing Marangoni and capillary flows. Experimental approaches to the effects of external physical fields (electric, magnetic, convection, and laser) and substrate properties on evaporation were also reviewed. Visualizing evaporation under various conditions can validate macroscopic models, while experiments with different substrates can validate molecular scale simulations, as substrate properties primarily affect evaporation by affecting capillary flow at the droplet bottom. This paper comprehensively reviewed numerical research on droplet evaporation, and analyzed the advantages, limitations, and development directions of various numerical methods.