Mancio Reis, F.M.Lavieille, P.Miscevic, M.2017-09-192017-09-192017http://hdl.handle.net/2263/62396Papers presented at the 13th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Portoroz, Slovenia on 17-19 July 2017 .The use of surfaces with wettability gradient aims to cover the surface with drops of small size to allow a large heat exchange. Thus, the action of the wettability gradient on the surface of the substrate is twofold: on the one hand, it allows the preservation of a dropwise condensation regime for which the heat exchange coefficient is particularly important and, on the other hand it allows the evacuation of the dispersed phase, thus promoting a renewal of the surface with very important heat exchanges during the nucleation phase. Thereby, a heat transfer enhancement factor up to 3.4 has been experimentally measured.6 pagesPDFenUniversity of PretoriaWettability gradientCondensation heat transferPresentation