Thermal interaction between two droplets in single-phase evaporation

Dropwise cooling is a major subject for both academic and industrial researches: the behavior of sessile droplets has been extensively investigated over many decades and a large body of literature is focused on heat-transfer mechanisms. The present work is focused on investigating the thermal transient occurring as two water droplets are gently released (We < 30) onto a heated solid surface: the single-phase-evaporation regime is here considered. Infrared thermography has been employed to experimentally evaluate the temperature trend at the solid-liquid interface: an apparatus has been built to carry out measurements from below, thus realizing a fully non-intrusive approach. As a numerical approach, a computational code has been developed to predict the involved physical phenomena: the three-dimensional energy-diffusion equation has been discretized through the finite-volume method and the simulations have been based on a structured non-uniform mesh.Modeling the transient within both the droplets and the solid substrate stands as the primary scope of this approach. Very goodagreement is shown between experimental and numerical results in terms of temperature trends, providing a thorough representation of droplet interaction over both the spatial domain and the evaporation and recovery time.