Beschreibung:
In this study, an evaporation coefficient representing the evaporation rate of vapor molecules was calculated in a vapor--gas binary mixture and non-equilibrium system using molecular dynamics simulation. The non-equilibrium herein refers to a state wherein the net evaporation of vapor molecules occurs, and the calculation system is composed of vapor molecules and non-condensable (NC) gas molecules. The evaporation coefficient in the non-equilibrium state was demonstrated to have almost the same value as that in the equilibrium state. The number density of NC gas molecules around the gas--liquid interface, which is related to the probability that vapor molecules are prevented from evaporating owing to molecular collisions, is shown to be independent of the system state. This makes the evaporation coefficient the same regardless of whether the system is in equilibrium or non-equilibrium. The evaporation coefficient also decreased as the molar fraction of the NC gas molecules increased. The increase in the molar fraction causes a higher number density of NC gas molecules around the gas--liquid interface, leading to an increase in the number of molecular collisions, which prevents vapor molecules from evaporating. Moreover, it was clarified that the change in the interface structure caused by the presence of NC gas molecules affects the velocity distribution of evaporation vapor molecules