Fabrication and characterization of glancing angle deposited nanostructured surfaces for enhanced boiling heat transfer

Abstract

Glancing angle deposition ( GLAD) process has been regarded as an efficient method to fabricate nanostructured surfaces for enhanced boiling heat transfer because of its simplicity and variety of material selection. In this study, the effects of structural parameters ( particularly the orientation and length of GLAD nanostructures) on boiling heat transfer were analyzed. The boiling heat transfer characteristics of Ag GLAD nanorods on a silicon substrate were examined using pool boiling experiments with deionized water. The vertical nanorod provided better performance than a slanted one, and a length of 200 nm was selected as the optimal length for maximizing the boiling heat transfer. A pool boiling critical heat flux of 20.6 W/cm(2) was obtained for a 200 nm tall Ag-vertical nanostructure, and 13.6 W/cm(2) was obtained for plain Ni-Ag layer on Si substrate. A 420% enhancement in the heat transfer coefficient was successfully achieved on a nanostructured surface compared to a plain Ni-Ag layer. (C) 2016 American Vacuum Society.