Measurement and Observation of Elementary Transition Boiling Process after Sudden Contact of Liquid with Hot Surface

A Fast response surface temperature measurement technique has been developed to investigate transient transition boiling phenomena after ethanol droplet impact on a nickel hot surface. Our motivation is to make clear the mechanism of boiling transition between nucleate and film boiling which is closely related the recovery of wetting on the hot surface being higher than the Leidenfrost temperature. In this study transient boiling phenomena during sudden contact of an ethanol sessile droplet on a hot solid surface has been investigated to understand what governs whether the solid surface keeps wet or not. The droplet impact boiling system is very simple and easier to observe but it includes the elementary transition boiling process. Since the transient transition took place within a couple ten milliseconds, observation with high speed video system and fast response surface temperature measurement technique are essential for better understanding of the transition boiling phenomena.