Infrared diagnostics of supersonic mixing of N2 and CO2 jets

A previously suggested method is applied to determine the specific energy of the antisymmetric vibrational mode of CO2 after injection into pure N2 and two mixtures of N2 and H2O. The technique is based on recording the intensity of the self-radiation and absorptivity in the 4.3 micron vibration-rotation band of CO2 and does not require knowledge of the gasdynamic flow parameters. The results indicate than an increase in the molar fraction of injected CO2 is accompanied by a reduction in the specific energy concentrated in the nu(3) mode of CO2. The extent to which the most widely used instantaneous mixing model is applicable to the description of actual streamlines in the nozzle is assessed. The calculated results were found to be very sensitive to the momentum transferred by the injected gas. The experimental values for the specific energy of the n(3) mode of CO2 are much less for mixtures containing small amounts of water than for dry mixtures.