A Thermodynamic Approach to Kinetics of Reactions

Abstract

Abstract The paper deals with a reacting fluid mixture. The balance equations are stated both in the Lagrangian and in the Eulerian description. The entropy principle is stated in terms of the entropy growths of the single constituents rather than by the classical entropy transport equation. Next the thermodynamic restrictions on the constitutive functions are derived by assuming that the partial pressures, entropies and internal energies are functions of the temperature and the pertinent mass density. As a consequence, the rate of reaction is shown to be proportional to the chemical affinity via a non-linear function of pressure, temperature, and mass fractions. The chemical affinity is then shown to be the derivative of the Gibbs free energy with respect to the reaction coordinate if the free energy density is in the standard form of a function of temperature and pressure while such is not the case if the model is adopted for a mixture of perfect gases.