Dissociative recombination in reactive flows related to planetary atmospheric entries

Abstract

Abstract. The Dissociative Recombination (DR) processes play a significant role in plasma chemistry. This article illustrates this role from the modeling point of view in the case of reactive flows related to atmospheric entry plasmas. Two situations are investigated, for which the studied plasma is nitrogen. The first configuration corresponds to the relaxation process behind a strong shock wave moving at high Mach number in a shock tube, the second one to the recombination taking place in an expanding plasma flowing in a diverging nozzle. In both cases, the collisional-radiative model CoRaM-N 2 , involving N 2 , N, N + 2 , N + and electrons, is implemented in an Eulerian 1D code able to compute the aerodynamic fields; calculations are performed in standard conditions. We show that, according to the rate coefficients used for the DR processes, the population density of the charged species especially N + 2 is strongly modified only for the post-shock flow.

Vibrational and electronic collisional-radiative model in CO2-N2-Ar mixtures for Mars entry problems

“…The significance of dissociative recombination has already been put in evidence behind shock fronts. 64 In addition, some excitation transfer processes between CO, NO, and N 2 have been implemented in the model. The rate coefficients are due to Gorelov et al 38 The excited states of the molecular species can be dissociated under electron impact.…”

Vibrational and electronic collisional-radiative model in air for Earth entry problems

“…Dissociative recombination, excitation transfer, charge exchange, and reassociation (concomitant neutral and charge exchange) have been taken into account. For the dissociative recombination process, the backward process (associative ionization) of which is involved in the production of the first free electrons and ions, 55 we have used the rate coefficients due to Motapon et al, 56 Peterson et al, 57 and Peverall et al 58 For excitation transfer, charge exchange and reassociation, we have used the rate coefficients given by Alekseev et al, 59 Capitelli et al, 22 Dunn and Kang, 60 Kossyi et al, 38 Losev et al, 61 Starik et al, 39 and Teulet et al 62 …”