Vanishing mean volume velocity in isothermal isobaric diffusion of a binary fluid mixture

摘要

It is shown that in isothermal isobaric diffusion of a binary fluid mixturethe mean volume velocity vanishes in the linear regime, independent of theequation of state. The partial specific volumes of the two components areuniform and constant in the process of mutual diffusion. The properties lead toa simple derivation of the de Groot-Mazur thermodynamic factor in the diffusioncoefficient. The properties also imply that the diffusive volume flux definedby Brenner is proportional to the mass current density, and is therefore not aquantity of independent interest.