Low Weber number droplet impact on heated hydrophobic surfaces

This study investigates low Weber number droplet impact on heated hydrophobic surfaces. Using synchronized high-speed optical and infrared (IR) imaging, we correlate the dynamics to spatial distribution of solid-liquid interfacial temperature, heat flux, total transfer droplet. The transferred a completely rebounding is also modeled analytically. Denoting drop diameter velocity as D v, find that Q scales D1.25v, which validated using experiments. A unique feature low-We non-wetting surfaces formation sub-millimetric entrapped bubble forms during receding. substrate temperature in region significantly higher than surrounding area due thermal conductivity air. Right after forms, local flux remains stable at inner contact line (bubble line), but decreases retracting primary outer line. As result, becomes increasingly important recedes. Nonetheless, overall reduced by 5.6% 7.1% surface temperatures 50 ℃ 65 ℃, respectively, reduces liquid-solid interface area. influence roughness quantified. Droplets rough have smaller maximum spreading diameter, leading lower rate. Moreover, average compared smooth surface, indicating larger resistance surface. Overall, findings highlight dominance conduction (as convection or evaporation) prominent mode impact.