VIOLATION OF THE SYMMETRY OF ONSAGER CROSS COEFFICIENTS IN ANISOTROPIC POROUS MEDIA IN THE PRESENCE OF A SURFACE CHEMICAL REACTION

Annotation. In the framework of linear nonequilibrium thermodynamics, Onsager's reciprocity relations L ij = L ji are the basis for the phenomenological description of coupled transport processes. In this paper, methods of nonequilibrium statistical mechanics and numerical modeling are used to investigate the conditions for breaking this symmetry for porous medium-reacting liquid/gas systems. It is shown that in anisotropic porous structures with a chaotic or ordered-heterogeneous distribution of pores, the presence of a fast irreversible surface chemical reaction leads to the emergence of microscopic vortex flows and spatio-temporal correlation between the components, which at the macro level manifests itself as an asymmetry of the matrix of kinetic coefficients || L ij ||. Based on the analysis of the generalized Navier - Stokes - Kirchhoff - Fick equations with reaction-type boundary conditions, correction terms to the classical Onsager relations are derived, proportional to the dimensionless parameter Da ∙ An ∙ Φ, where Da is the Damköhler number, An is the anisotropy parameter, and Φ is the nonlocal chemical affinity factor. The results obtained are important for improving the accuracy of models in catalysis, membrane separation, geochemistry, and biotransport . Key words: nonequilibrium thermodynamics, Onsager relations, cross effects, anisotropic porous medium, reaction-diffusion transfer, surface kinetics.