Abstract
The influence of different atmospheric pressures on the water evaporation process can be attributed to variations in Knudsen layer thicknesses and air particle densities within it. To investigate the influence, a nonequilibrium molecular dynamics model describing the process is introduced in this paper. Using both evaporation rate and virial pressure, water evaporation processes under four atmospheric pressures are investigated and analyzed. Higher evaporation rates are observed at the early stages of evaporation with higher atmospheric pressure. This anomaly can be attributed to the frequent short-range interaction between air and water molecules, caused by the increase of air molecules density. This can be attributed to the intense interaction between the high density of air molecules in the Knudsen layer and water molecules at the liquid surface, which contributes to the high evaporation rates. In the latter stages of evaporation, the low density of air molecules in the Knudsen layer may weaken the interaction within this layer, thereby further increasing the evaporation rates.
