Surface thermal capacity and its effects on the boundary conditions at fluid-fluid interfaces

Abstract

We have formulated a generalization of the energy boundary condition for fluid-fluid interfaces that includes the transport of the Gibbs excess internal energy. A newly measured surface property - the surface thermal capacity c(sigma) - appears in the result, and couples the temperature and velocity fields. If this term is not included in the energy boundary condition at liquid-vapor interfaces, the energy-conservation principle cannot be satisfied during steady-state evaporation of H(2)O(l) or D(2)O(l) . The c(sigma) term is possibly important in a number of other circumstances, and its importance can be determined from the magnitude of two nondimensional numbers.