Computational simulation of emission spectra from shock-layer flows in an arcjet facility

This paper reports computational comparisons with experimental studies of a nonequilibrium blunt-body shock-layer now in a high-enthalpy arcjet wind tunnel at NASA Ames Research Center, The experimental data include spatially resolved emission spectra of radiation emanating from a shock layer formed in front of a flat-faced cylinder model. Multitemperature nonequilibrium codes are used to compute the conical nozzle now, supersonic jet, and shock-layer now. A line-of-sight (LOS) radiation code is employed to predict the spectra from the computed flowfield. Computed LOS emission intensities are directly compared with the experimental data at several axial locations along the stagnation streamline, Various LOS-averaged flow properties, such as vibrational and rotational temperatures, and species number densities, deduced from the experimental spectra, are compared with computed results. Comparisons provide an assessment of thermochemical equilibration processes in an arcjet shock layer.