Thermodynamic derivation of the new form Stefan–Maxwell relations and algebraic equations for the transport coefficients correlated with diffusion-thermal processes in multicomponent continuous medium

Methods of thermodynamics of irreversible processes, using the principle of reciprocity of Onsager–Casimir obtained defining relations for the thermodynamic diffusion and heat flows in the gas mixture, in particular, derived exact Stefan–Maxwell relations for multicomponent diffusion flows and their corresponding expression for the heat flow. Accurate defining relations "forces through flows" allowed to obtain phenomenologically algebraic formulas relating the coefficients of binary and multicomponent diffusion, thermodiffusion relations, the coefficients of thermal diffusion and thermal conduction. All relations derived completely identical in structure similar relations obtained in the kinetic theory of multicomponent mixtures of monatomic gases of moderate density within the first approximation of the Chapman–Enskog. Since the thermodynamic approach is not associated with a specific microscopic model postulating the medium, the results of this work are universal and suitable for the description of a wide class of continuous media (polyatomic gas mixtures, dense gases, liquid solutions, etc.).