par Brandis, Aaron;Laux, Christophe;Magin, Thierry 
;McIntyre, Timothy J.;Morgan, Richard
Référence Journal of thermophysics and heat transfer, 28, 1, page (32-38)
Publication Publié, 2014
;McIntyre, Timothy J.;Morgan, RichardRéférence Journal of thermophysics and heat transfer, 28, 1, page (32-38)
Publication Publié, 2014
Article révisé par les pairs
| Résumé : | Radiation during Titan entryis importantatlower speeds (around 5-6 km/s) compared to other planetary entries due to the superequilibrium formation of the highly radiating species, cyanogen, in the shock layer (with concentrations beingup to50% higher than equilibrium).A collisional-radiative model has been developed to predict the nonequilibrium populations of cyanogen and nitrogen and the subsequent radiation emitted during entry into the Titan atmosphere. A vibration state specific model based on Schwartz-Slawsky-Herzfield theory, which includes excitation and deexcitation reactions for 47 vibration states of the ground electronic state of nitrogen, was incorporated into a previously developed collisional-radiative code. The model has been tested against measurements obtained with the Electric Arc Shock Tube at the NASA Ames Research Center and the X2 shock tube at the Universityof Queensland. The vibrationally specific nitrogen collisional-radiative simulations show better agreement with experimental dataintermsofthe initialriseofthe radiation, however, generallydonot offer improvedagreement in terms of the absolute intensity level. The results from this paper indicate that the collisional-radiative models overestimate the level of radiation by approximately a factor of 1.5-10, depending on the condition. Furthermore, results presented in this paper show that, by adjusting the excitation rate of cyanogen and dissociation of rate of nitrogen, good agreement between experiment and simulation can be obtained. |
