Self-assembly carbon nanotube nanoporous coatings with great durability for highly efficient boiling heat transfer

Abstract

Fabricating a high-performance and stable nanocoating to improve boiling heat transfer is of vital importance to ensure the safety, efficiency and cost-effectiveness of heat energy transfer, conversion and management systems. Here, a self-assembly multi-walled carbon nanotubes (MWCNTs) nanoporous coating with great durability was developed by utilizing the facile and low-cost nucleate boiling self-assembly method. The MWCNTs nanoporous coating can achieve highly efficient boiling heat transfer. It exhibits enhancements of 86.4% in critical heat flux (CHF) and 72.6% in maximum heat transfer coefficient (HTC) as compared to the plain copper surface. Additionally, when compared with the self-assembly graphene oxide laminate coating, the HTC of the MWCNTs nanocoating is also evidently augmented at the same given heat flux. The superior boiling performance is explained by its surface characteristics. The formation of the MWCNTs nanoporous coating improves the surface wettability, roughness and capillary wicking, thus facilitating liquid replenishment and delaying CHF. It also significantly increases the number of bubble nucleation sites and the bubble departure frequency to accelerate heat transfer through liquid-vapor phase change, thereby significantly increasing the HTC. The proposed MWCNTs nanoporous coating shows great potential for incorporation in applications that require engineered heat transfer and advanced thermal management.