Investigation of surface structure-wettability coupling on heat transfer and flow characteristics in nanochannels

Abstract

• The effect of surface wettability and roughness coupling is investigated by MD. • The progressively subdivided rough nanostructures are established. • The effect of wettability becomes slight when the scaling parameter exceeds 1.0. • The enhanced solid-fluid interaction energy reveals the microcosmic mechanism. The high integration of electronic devices has become an irresistible trend, what bottlenecks its development is the heat dissipation in micro/nanoscale. Surface roughness and wettability are the two main factors affecting convective heat transfer in nanochannels. However, the combined effects of wettability and roughness are still unclear. Consequently, by molecular dynamics simulation, the combined impact of wettability and roughness on heat transfer and flow characteristics are investigated in rectangular nanochannels with various wettability and progressively subdivided roughness. The results show, when the surface becomes more hydrophilic and subdivided, the temperature and Nu increase, whereas the temperature slip decreases, leading to an efficient improvement of the heat transfer process. Moreover, the velocity slip decreases, and the flow resistance increases, so the fluid flow process is relatively inhibited. Particularly, the effects of wettability and roughness are inconsonant. For the cases in this research, when the wettability scaling parameter exceeds 1.0, the hindrance of wettability to velocity development becomes slight. However, the improvement of wettability to temperature development is still significant. Microscopically, it’s found more atoms accumulate at the solid-liquid interface, and solid-liquid interaction energy enhances. This investigation provides theoretical guidance for the efficient cooling of micro/nano electronic devices.