Mechanism of Wettability–Rough Morphology Coupling on Convective Heat Transfer in Nanochannels

Highly integrated micro-nano electronic devices suffer from severe heat dissipation challenges, and flow cooling in nanochannels is an effective solution. During convective heat transfer at liquid-solid interfaces, surface wettability and rough morphology are key parameters governing thermal transport; however, their combined effects remain unclear. In this study, molecular dynamics simulations are utilized to examine the synergistic effects of surface wettability and nanopillar arrays on thermal transport and fluid dynamics within nanochannels. The results show that increasing surface hydrophilicity and roughness reduces the thermal slip length and increases the Nusselt number, thereby enhancing heat transfer performance in the nanochannel. From a fluid dynamics standpoint, velocity slip length decreases while the relative friction coefficient increases, signifying greater flow resistance. For the present model, the enhancement in heat transfer induced by increased wettability is significantly greater than that caused by increased roughness, whereas their effects on flow resistance are difficult to distinguish the dominance. At the microscale, increased wettability and roughness facilitate the accumulation of fluid atoms near the liquid-solid interface. The elevated interaction energy between solid platinum atoms and fluid argon atoms is identified as the primary mechanism underlying thermal transport enhancement in nanochannels. This investigation offers valuable insights for the optimized thermal management of micro-nano electronic devices.