Phenomenological Theory of Transport Processes in Fluids

Abstract

In this article a general theory of transport processes in fluids, developed from equations of hydrodynamics and thermodynamics which have been generalized for application to multicomponent systems, is presented. The equations for the flow of entropy and masses of components of the fluid, obtained from the local entropy dissipation, are used to treat the processes of viscosity, mobility, diffusion, electrical and thermal conductance, thermal transpiration, thermal diffusion, and the homogeneous thermoelectric effect. Reciprocal relations and other properties of the coefficients associated with each process are obtained and also inter-relationships between the coefficients of the various processes. The special conditions for the steady state, the state of pure thermal conduction, and the state of equilibrium are considered. Investigation of the steady state in thermal diffusion indicates that mass flow may persist, contrary to the usual assumption in treatment of experimental data.