Molecular insights into vibration-induced phase change dynamics of low-boiling-point refrigerant

Abstract

Vibration-induced evaporation and boiling has attracted great attention due to its prominent efficiency. However, the understanding of low-boiling-point refrigerant phase change on various vibration and wettability conditions remains to be investigated. In this study, molecular dynamics simulations are performed to explore the vibration-induced phase change performance of R1336mzz(Z) nanofilm over a copper substrate. Results found that the phase change mode of R1336mzz(Z) nanofilm can be divided into diffusive evaporation, nucleate boiling, and film boiling/cavitation. For one thing, the residual ratio of R1336mzz(Z) molecules lies on the vibrational amplitude (A) and frequency (f), with a linear relation to Af3/2 when Af3/2 is less than 150. For another, the molecular motion is originated from joint action of thermal momentum and mechanical tensioning, leading to film boiling or cavitation by tunning the predominant mechanism. In addition, the impacts of interfacial wettability on vibration-induced phase change are discussed in terms of the heat transfer ability and potential barrier for bubble nucleation. Results reveal that hydrophilic surface causes strong attraction at near-wall region to increase heat transfer, while hydrophobic surface shows weak potential barrier, which promotes the occurrence of bubble nucleation. These findings deliver insights to broad the use of high-frequency vibration in industrial applications.