Evaporating meniscus in a nanochannel: comparison of continuum models and nonequilibrium molecular dynamics simulations

Studies of evaporating confined menisci are important for a wide range of applications such as micro heat pipes and boiling. Continuum level models suggest a sharp increase in the evaporative heat flux in the region where the liquid-vapor interface is close to the heated wall, often identified as the transition region or microregion. However, this prediction is based on the assumption of constant wall temperature. We develop a modified model of the microregion evaporation that accounts for heat conduction in the wall and observe reduction in the local evaporation rates compared to the previously published studies of the similar configurations. The predictions of the continuum models are compared with the non-equilibrium molecular dynamics simulations of menisci in a channel of height 16 nm with regions of heat input and output at the walls. Temperature profiles and mass transfer rates are discussed.