Enhancement of Pool Boiling Heat Transfer Performance of R-134a on Microporous Al@GNPs Composite Coatings

Abstract

Pool boiling has been widely employed in electronic, power production and refrigeration systems due to its high efficiency in heat transfer. However, the investigation and application of microporous Al matrix composite coatings to enhance the pool boiling heat transfer (BHT) are very limited. In this study, graphene nanoplatelets reinforced Al matrix (Al@GNPs) composite coatings are fabricated by combining mechanical milling, screen printing and sintering techniques to investigate the pool boiling heat transfer using R-134 as working fluid. The experimental data were obtained at a saturation temperature of 10 °C for heat fluxes ranging from 9.04 kW·m−2 to 73.57 kW·m−2. The effect of various coating thicknesses on boiling characteristics and heat transfer coefficient (HTC) of R-134a were studied and presented in detail. Our results demonstrate that the HTC obtained for Al@GNPs-4 composite coated heating surface is 143% higher than the plain Al heating surface. Enhanced nucleation sites and increased bubble pumping action are the main reasons for the augmented BHT performance on the Al@GNPs composite coated heating surfaces.