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 arc jet wind tunnel at NASA Ames Research Center, The experimental data in clude spatially resolved emission spectra of radiation emanating from a shock layer formed in front of a flat-faced cylinder model. Multitem perature nonequilibrium codes are used to compute the conical nozzle n ow, supersonic jet, and shock-layer now. A line-of-sight (LOS) radiati on code is employed to predict the spectra from the computed flowfield . Computed LOS emission intensities are directly compared with the exp erimental data at several axial locations along the stagnation streaml ine, Various LOS-averaged flow properties, such as vibrational and rot ational temperatures, and species number densities, deduced from the e xperimental spectra, are compared with computed results. Comparisons p rovide an assessment of thermochemical equilibration processes in an a rcjet shock layer.