Evaporation of sessile droplet on surfaces with various wettability

Abstract

The evaporation kinetic mechanisms of sessile droplets are investigated with numerical simulations. A sessile droplet evaporation model, combining flow, heat transfer, and vapor transport equations, is developed based on Arbitrary Lagrange-Euler (ALE) method. The numerical results are validated to be in good accordance with the experimental results in the literature. The results show the formation and evolution mechanisms of the internal flow in an evaporating droplet are controlled by the thermal conduction distance and evaporative cooling effect. As the contact angle decreases, the single-vortex flow inside an evaporating droplet transforms into a multi-vortex flow. Furthermore, the maintenance of the multi-vortex flow inside a flat droplet requires an appropriate volume. The results presented in this work provide a theoretical basis and practical guidance for exploring more efficient heat transfer techniques.