Significantly enhanced convective heat transfer through surface modification in nanochannels.

Highlights • Roughness enhances heat transfer between the wall and the fluid. • The enhancement stems from the increased contact area between the wall and the fluid. • Nano-roughness shows certain degree of lubricating effect. • Heat convection in the nanochannel studied in this work is diffusion dominated. • Surface coating with an intermediate vibrational spectrum can enhance heat convection. Abstract The subject of convective heat transfer in micro-/nano-scale channels is of utmost importance for the effective cooling of small-scale electronic devices with high power density. The overall heat convection in these channels largely depends on interfacial (wall-fluid) thermal transport. In this work, we demonstrate that a carefully designed surface topology can enhance heat dissipation in nanochannels. Specifically, we found that both uniformly and randomly distributed surface roughness can substantially increase the overall heat transfer between the wall and fluid in the nanochannels. Moreover, we reveal that depositing a coating layer, of which the vibrational density of states bridge those of the walls and the flowing fluid, can significantly enhance wall-fluid interfacial heat transfer. This work reveals the critical effect of surface topology and material choice of the channel wall on heat dissipation in nanochannels, which is important for the cooling of small-scale devices. [ABSTRACT FROM AUTHOR]