Molecular dynamics simulation of liquid argon flow in a nanoscale channel

Abstract

The convective heat transfer in the Micro/ Nanoscale channel is of significant importance in engineering applications, and the classical macroscopic theory is invalid at depicting its physical processes and mechanisms. In this study, molecular dynamics (MD) simulations are conducted to investigate the heat transfer of liquid argon flow through a nanoscale channel. The results show that the fully developed bulk temperature agrees with the continuum based solution of the analytical energy equation at channel height 24 nm, while this agreement reduces with the decrease of the height due to the nanoscale features. At height 6 nm, velocity slip exists around the hydrophobic wall, and enhanced near-wall viscosity of liquid and reduced velocity slip length are observed at larger fluid–wall interaction strength. A region around 2 Å wide without liquid atoms is formed at the hydrophilic wall, leading to a zero velocity in this hollow domain and a no-slip boundary condition. Most importantly, the thermal slip length is remarkably dependent on the liquid density layering in the proximity of the wall and inversely proportional to the first peak value of liquid adjacent to the interface. This observation provides a new idea to tune the heat dissipation properties at the fluid–wall interface by controlling the liquid density layering.