Atomistic insights into the microscope mechanism of solid–liquid interaction influencing convective heat transfer of nanochannel

Abstract

Nanochannel cooling technology is widely used in the heat dissipation systems of various micro/nanoscale electronic devices or components. The consideration of resistance loss and the optimization of heat dissipation are of great significance for the widespread application of nanochannel cooling technology. A model of convective heat transfer in nanochannel with constant wall temperature is established with molecular dynamics method. The effects of solid–liquid interaction on flow and heat transfer characteristics are investigated. The microscopic mechanisms of the solid–liquid interaction influencing heat transfer performance and flow resistance of nanochannel are explored from the atomic level. The results show that the enhancement of the solid–liquid interaction leads to the increases of the coupling degree of vibration frequency between wall and liquid atoms and the orderliness of microstructure of first fluid layer, and finally facilitates heat transfer between nanochannel wall and liquid. The Nusselt number in nanochannel is not a constant and decays exponentially with the increase of temperature jump length. Meanwhile, as the solid–liquid interaction increases, the slip length decreases and the friction factor increases, which are attributed to the augment of the static structure factor, resulting in more fluid atoms in near-wall region are firmly locked by the wall. The friction factor in nanochannel not only depends on the Reynolds number, but also is closely related to the slip length. To further evaluate overall heat transfer performance of the nanochannel that considers flow resistance, the comprehensive performance coefficient is discussed. It’s found that the solid–liquid interaction is effective in improving the overall heat transfer performance of the nanochannel within a certain range.