Nanoscale liquid-vapor phase change characteristics of binary mixtures from molecular dynamics perspective

Abstract

Nanoscale thin liquid film boiling of a binary liquid mixture subjected to extremely rapid heating within molecular dynamics framework is the focus of our study. A three-phase MD simulation domain is considered where liquid argon-krypton (Ar-Kr) binary mixture rests over a solid Platinum (Pt) like substrate. The molecular system starting from freezing state is subjected to non-equilibrium boundary heating following a sufficient equilibration period to induce liquid–vapor phase change process. Depending on the mixture composition and boundary heating rate, four distinct phase change scenarios have been observed. Characteristics of different phase change scenarios have been studied in terms of important system parameters such as transient atomistic distribution, temperature, pressure, evaporation history, onset of liquid cluster splashing from the wall along with atomic kinetics parameters like COM (Center of Mass), and MSD (Mean Square Displacement). Addition of Kr with Ar that is less volatile compared to Ar, has been found to result in a delay in the evaporation onset and decrease in interaction energy. As a consequence, with the increase of Kr fraction in the binary mixture, the mobility of the evaporated atoms is hindered and the onset temperature of liquid splashing from the wall that resembles generation of “Leidenfrost Film” changes. Also, the near wall atomistic energetics is significantly influenced by mixture composition. Finally, a contour of various phase change modes for Ar-Kr binary mixtures has been presented as a function of mixture composition and boundary heating rate. Present work has been found to be aligned with contemporary works in the context of the derived heat transfer properties.