Molecular dynamics study of evaporation induced by locally heated argon liquid

In this study, we conducted molecular dynamics simulations of the evaporation of locally heated argon liquid to construct the kinetic boundary condition (KBC) for the evaporation. The KBC denotes the boundary condition of the Boltzmann equation, and the mass, momentum, and heat fluxes through the interface can be determined by solving the Boltzmann equation with the KBC. From the results, we established a method for constructing the KBC for the evaporation of locally heated argon liquid. Furthermore, we found that the velocity distribution of the KBC immediately after liquid heating becomes anisotropic, which means that the normal and tangential temperatures composed of outgoing molecules from the liquid phase to the gas phase take different values when the liquid interface is heated momentarily. From the present study, we can elucidate the mechanism of the occurrence of net evaporation mass flux due to the locally heated liquid film, e.g., the spot heating by infrared radiation.