Experimental research on wetting behavior of refrigerant-oil mixture on micro/nanostructured surface

The wettability of micro/nanostructured surface is a key property for its application in enhancing the boiling heat transfer of refrigerant-oil mixture. The objective of this research is to experimentally investigate the wetting behavior of refrigerant-oil mixture on micro/nanostructured surface. Three types of surfaces including plain copper surface (PS), micro/nanostructured surface (MNS) and micro/nanostructured surface with fluorinated self-assembled monolayer (MNFS) were fabricated; and the wetting behavior of pure R141b as well as R141b-NM56 mixtures with different oil concentrations on three types of surfaces was measured. The experimental results show that the protuberant liquid film is formed during the wetting of refrigerant-oil mixture on MNS or PS, but does not exist on MNFS; the presence of F-SAM or micro/nanostructure modified by F-SAM reduces the surface wettability, while the presence of micro/nanostructure increases the surface wettability; oil increases the wettability of refrigerant on MNS, while it reduces the wettability of refrigerant on MNFS. (C) 2016 Elsevier Ltd and International Institute of Refrigeration. All rights reserved.