Nonlinear mass and heat transfer across liquid-vapor interfaces

Nonlinearities in mass and heat transfer across liquid-vapor interfaces are studied based on models from irreversible thermodynamics and the kinetic theory of gases. Specifically, we present the nonlinear extension of the well-known Hertz-Knudsen-Schrage (HKS) model of kinetic theory for mass flux and a corresponding relation for heat transfer. It is shown that this extended model stands in good agreement with established kinetic theory models for zero heat flux. The extended HKS model is linked to the force-flux relations of nonequilibrium thermodynamics by determining their nonlinear interface resistivities, which depend not only on the interface temperature, but also on mass and heat flux. Nondimensionalization based on temperature and saturation pressure yields resistivities independent of the local temperature. Reevaluation of recent Molecular Dynamics data for resistivities [Homes and Vrabec, Phys. Fluids 36, 022122 (2024)1070-663110.1063/5.0193522] reveals distinct nonlinearities.