Measurements of Carbon Dioxide Nonequilibrium Infrared Radiation in Shocked and Expanded Flows

RADIS: A nonequilibrium line-by-line radiative code for CO2 and HITRAN-like database species

“…JAXA included CO 2 modeling in the SPRADIAN radiation code. So far only equilibrium results [16] have been published although work is underway to simulate nonequilibrium spectra [17]. The PASTIS [18] radiation code, developed to study the emission of a nonequilibrium CO 2 plasma, is limited to the CO 2 dissociation products and does not include CO 2 itself.…”

Analysis of the JAXA Nonequilibrium Infrared Emission Spectra for Mars Entry Conditions

“…22 in Ref. [6]). They attributed the discrepancies to flow heterogeneities and to a nonequilibrium vibrational distribution.…”

“…In the forebody, the radiation is dominated by visible and UV emission of CO, CN and O 2 [2? ]. In the afterbody, the recombination of CO 2 is responsible for a radiative heat flux larger than convective heating [3], but thee are still large uncertainties on the radiative fluxes [4]: on the eve of new Mars missions, a renewed computational [5] and experimental effort was engaged at NASA [4], JAXA [6] and UQ [7] to model nonequilibrium CO 2 radiation.…”

“…The JAXA expansion tube experiment of Takayanagi et al [6] was one of the first experiment to measure absolute intensity CO 2 infrared spectra in an expanding flow. The experiment was performed in the JAXA HVST expansion-tube facility, with a model placed at the exit of the tube, and a flow velocity of 5.68 km/s.…”

“…The authors also measured absolute emission spectra of the 4.2 µm band of CO 2 at three locations: in the free flow, in front of the model, and behind the model. Takayanagi et al [6] attempted to fit the free flow experimental spectrum with the SPRADIAN code [8] assuming equilibrium at temperatures ranging from 1500 to 4000 K. However, they obtained a surprisingly large disagreement for all conditions considered (see Fig. 22 in Ref.…”