Enhanced nucleate boiling heat transfer on bubble-induced assembly of 3D porous interconnected graphene oxide/silver nanowire hybrid network

Abstract

Due to an increasing trend of size diminution, integration, and multifunctionality, the heat load on electronic devices is constantly increasing. Though nucleate boiling is regarded to be the most efficient mode of heat transfer, it still has much room for improvement in terms of heat transfer coefficient and critical heat flux. Thus, extensive research efforts have been devoted to the preparation of functional heating surfaces for enhanced boiling. This study presents nucleate boiling enhancement on a 3D porous graphene oxide/silver nanowire hybrid film. Then, boiling experiments were conducted under atmospheric pressure using a custom-developed boiling apparatus with a flat copper heating surface. Bubble-induced graphene oxide/silver nanowire hybrid deposition structures were analyzed through a series of characterizations such as Field Emission Scanning Electron Microscopy, Energy Dispersive X-Ray Spectroscopy, profilometry, and contact angle analysis to elaborate the physical mechanism behind the nucleate boiling enhancement. Among three tested concentration ratios (GO:AgNW; 0:1, 1:1, 1:5 by weight), maximum heat transfer coefficient and critical heat flux enhancement were achieved at a GO:AgNW concentration ratio of 1:5 owing to the improved surface characteristics such as surface area, bubble nucleation site density, lateral heat conduction, and capillarity. Heat transfer coefficient and critical heat flux enhancements of graphene oxide/silver nanowire hybrid surface reached 196.6% and 182.4%, while the upgrades on graphene oxide surface were 112.4% and 135.3%, respectively.