Droplet growth behavior during condensation on SAM coated hydrophobic surface

Abstract

Condensation is an important heat and mass transfer method that is used in various industrial areas. In a heat exchanger, an ideal condenser surface should be able to shed condensate drop as early as and quickly as possible and possess large quantities of nucleate sites that enable rapid drop nucleation and growth for continuous condensation. The purpose of this study is to experimentally analyze the transient characteristics of the droplet growth and the heat transfer during a dropwise condensation process on the hydrophobic surfaces. In case of heat transfer performance, it was verified that the heat flux and heat transfer coefficient are maintained highly with decrease in surface wettability. In particular,heat flux and heat transfer coefficient change drastically is observed significant difference depending on wettability in the regime where liquid droplets coalescence is dominant. Accordingly, it is judged that the droplet growth behavior in the beginning at the time of dropwise condensation exerts considerable effect on the overall surface heat transfer performance.