A Bhatnagar-Gross-Krook kinetic approach to fast reactive mixtures: Relaxation problems

The paper deals with a consistent BGK-type approximation for the Boltzmann-like equations which govern the evolution of a gas undergoing bimolecular chemical reactions. In particular, model equations, specifically devised for physical situations in which chemical relaxation is as fast as mechanical relaxation, are discussed in comparison to previous models. This BGK approach preserves the main features of the reactive Boltzmann equations, including law of mass action and H-theorem. Numerical results illustrating the effects of the several varying parameters on the relaxation to equilibrium are presented and commented on.