Boiling heat transfer on modified copper surfaces with inhomogeneous wettability

Abstract

Experiments were carried out on biphilic surfaces made using two technologies. The first technology was the deposition of a fluoropolymer through special masks (100 μm spots and 500 μm pitch; 50 μm spots and 200 μm pitch) onto a smooth or pre-modified (silica micrococoon arrays) copper surface. The second technology consisted in the deposition of fluorinated methoxysilane on a copper surface with arrays of caverns preliminarily created by laser ablation (caverns size of the order of 70 μm, pitch - 780 μm), as a result of which deposition the caverns became superhydrophobic. The experiments were carried out on distilled water at atmospheric pressure. For all surfaces, a significant intensification of heat transfer has been achieved, compared with a smooth copper surface. All described biphilic surfaces were compared with similar surfaces without hydrophobic treatment, that is, non-biphilic (smooth surface, arrays of micrococoons, arrays of caverns). For all surfaces, the key contribution of biphilic properties to the intensity of heat transfer is shown in comparison with other related types of processing.