## IMPROVED RADIATION CALCULATIONS FOR HYPERSONIC REENTRY FLOWS USING EFFICIENT DATABASING SCHEMES
## AbstraktEfficient databasing schemes of emission and absorption cross sections are developed to model radiation from nonequilibrium gas flows. To develop a new model, the relevant absorption and emission coefficient cross-sections for the typical air plasma species formed during earth reentry are extracted. For bound-bound transitions, line information including line-center wavelength and emission and absorption coefficients without a line shape factor is stored. For bound-free and free-free transition, absorption cross sections are calculated using correction factor data, and are databased with relatively coarse wavelength spacing. For flow nonequilibrium, a rate equation approach including both collisional and radiatively induced transitions is needed to calculate the electronic state populations. By using the quasi-steady-state assumption (QSS), excited state populations of nonequilibrium gas species were calculated in terms of flow temperatures, species concentrations, excitation cross-sections, and radiative life times. The accuracy and efficiency of the databasing scheme was examined by comparing results of the database with those of NEQAIR. The flowfield around the Stardust blunt body at the speed of about 12 km/s modeled by the direct simulation Monte Carlo (DSMC) method was used for demonstration. |

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