ISSN Online: 2377-424X
International Heat Transfer Conference 12
Dropwise condensation heat transfer on ion implanted metallic surfaces
Sinopsis
Dropwise condensation can be achieved on the surfaces of several different metallic materials (Copper,
Titanium, Aluminum, High-grade Steel and Hastelloy) which have been treated by ion implantation with
nitrogen, oxygen or carbon ions. Stable dropwise condensation has been found for a long-time continuous testing phase over more than four years for some of the materials tested. Heat transfer measurements have been
performed for the condensation of pure quiescent steam near atmospheric pressure. The measured heat transfer
coefficients were up to more than 17-times larger than that ones of filmwise condensation, its values being
dependent on the amount of ions implanted. The measured heat flux increases with increasing surface subcooling
approaching a maximum which is dependent on the surface material used. Further subcooling results in a
decrease of the heat flux. An ion diffusion process along the surface allows a locally restricted ion implantation
which is a strong simplification in the production of appropriate surfaces.