Simulation of droplet evaporation under the dual influence of surface wettability and nucleate boiling

Droplet evaporation has great scientific significance in industrial and agricultural production as well as natural meteorological processes. Among many factors that affect evaporation, wettability and wall temperature are among the most important. The Lattice Boltzmann Method (LBM) was used to explore the effects of evaporative wall wettability and wall temperature on the Constant Contact Angle (CCA) model. We constructed a dual-distribution gas-liquid phase transition model and found that the higher the wall temperature, the more rapid the evaporation; however, nucleate boiling was more likely to occur at high temperatures, making the CCA (and thus evaporation) unstable. Compared to hydrophobic surfaces, hydrophilic surfaces have larger droplet spreading area, and generally higher evaporation rate; as the contact diameter decreased, droplet diffusion occurred and evaporation to dryness was observed. Droplets on hydrophobic surfaces tended to form nucleus of boiling, thus generating bubble and gas films. After the droplets shrunk and stabilized, the contact diameter reduced and evaporation slowed. Droplet evaporation can be regulated to improve energy efficiency depending on different applications.

Automated summary

Droplet evaporation plays a crucial role in industrial and agricultural production as well as natural meteorological processes. Wettability and wall temperature are key factors influencing evaporation. Higher wall temperatures accelerate evaporation, but can also lead to instability. Hydrophilic surfaces exhibit higher evaporation rates compared to hydrophobic ones, which are more prone to nucleate boiling.