MODELING OF NONEQUILIBRIUM RADIATION PHENOMENA - AN ASSESSMENT

The present understanding of shock-layer radiation in the low-density regime, as appropriate to hypersonic vehicles, is discussed. Calculate d spectra using the NONEQ and GENRAD computer programs are compared wi th experimental spectra recorded at NASA Ames's electric arc driven sh ock-tube facility. The computations predict the intensity of the N-2()(1(-)) system very well, but overpredict the intensities of various a tomic O and N transitions and underpredict the intensities of the N-2( 2(+)) band system. To compute the correct electronic populations, it a ppears that the quasi steady-state formulation must be expanded to inc lude more individual electronic states. However, this may cause some c omputational difficulties and will require excitation rate data for ma ny states, which are not well known.