An experimental investigation of sessile droplets evaporation on hydrophilic and hydrophobic heating surface with constant heat flux

Droplet evaporation widely exists in the daily life and industrial production. In most of previous experimental studies, the evaporation of sessile droplets was conducted under a constant substrate temperature condition. However, drops often evaporating on a heating surface under a constant heat flux condition in many practical applications. In this paper, we have carried out an experiment on sessile 3 μl DI water droplets evaporated on hydrophilic and hydrophobic heating surfaces under constant heat flux in the range from 1153 W/m² to 6919 W/m². A high-speed camera was used to record the changing shapes of two sessile droplets on a hydrophilic and a hydrophobic heating surface placed side by side. The droplet height, dynamic contact angle, droplet contact diameter, evaporation mode and evaporation rate are presented.