Enskog’s kinetic theory of dense gases for chemically reacting binary mixtures. I. Reaction rate and viscosity coefficients

The symmetric moderately dense reaction A+A⇌B+B is analyzed within the framework of Enskog’s equation by using the Chapman–Enskog method. For the last stage of a chemical reaction–where the affinity is considered a small quantity–the constitutive equations for the reaction rate densities and the pressure tensor of the mixture are calculated in terms of the thermodynamic forces: affinity, divergence and gradient of the mixture’s velocity. The transport coefficients of forward reaction rate, “bulk” reaction rate, shear, bulk and “chemical” viscosities do depend on the activation energy and on the increasing of the density of the mixture. It is shown that: (i) the pressure of a chemically reacting mixture of dense gases is larger than that of a non-reactive mixture of dense gases; (ii) the influence of the chemical reactions on the transport coefficients are more striking for smaller values of the activation energy; (iii) all transport coefficients are affected by the increase of the density of the mixture.