Numerical study of elemental demixing in atmospheric entry flow regimes near local thermodynamic equilibrium

Abstract

We apply a recently derived and explicitly closed form of the equations of chemically reacting flows under local thermodynamic equilibrium to investigate its applicability to hypersonic flows. This new model rigorously takes into account the effects of the separation of chemical elements due to the differential diffusion of species, known as elemental demixing. We study the particular case of a neutral 5-species air flow around a blunt body configuration, with realistic free stream conditions corresponding to the later stages of a re-entry trajectory of a future space mission. In order to assess to what extent the local equilibrium assumption holds for the consider physical problem, we compare our results with other ones obtained using a chemical non-equilibrium model. Particular attention is paid to the distribution of oxygen elements in the flow field