Vibrational relaxation of CO2(m,n(l),p) in a CO2-N2 mixture along a stagnation streamline

Abstract

The knowledge of the vibrational relaxation reaction rates of diatomic and triatomic molecules is required for the modeling of numerous gazeous mixtures such as the earth atmosphere (involving the radiation tranfer phenomena), exhaust plumes, afterbody wakes, Mars atmosphere, shock waves and chemical lasers. It enables a better understanding of the rates and products of the chemical reactions that involve this species and provides the populations of the levels that radiate. In this study, we consider the few lowest vibrational levels of a CO-2 — N-z mixture and the V-T and V-V energy transfer processes between these levels. The reaction rates are given by experimental and theoretical studies and by different surveys of data supplied by a bibliographic search. Then, the population distributions along a stagnation streamline are determined for the various vibrational levels and according to the different models with the CELHYO code developed at ONERA, using a new one-dimensional approach. Usual assumptions concerning the vibrational relaxation of CO-2(m,nl,p) are discussed.