Theoretical and experimental investigations of I.R. radiation transfer in vibrationally nonequilibrated molecular gas containing CO2 and CO

Combined theoretical calculations are presented for the processes of vibrational relaxation and radiative energy transfer for the case of vibrationally nonequilibrated mixtures of CO2 and CO containing molecular gases moving in a supersonic nozzle. Basic regularities are established which determine radiation intensity and emissivity of a vibrationally nonequilibrium gas flow. The conditions are found under which the measurement of radiation intensity in the vibrational rotational 4.3 and 2.7 micron CO2 bands and the 4.7 micron CO band make it possible to determine reliable diagnostics for vibrational energy exchange processes. It is shown that the effect of vibrationally nonequilibrated molecules distribution on the emissivity is relatively small, which imposes certain restrictions on the methods of absorptivity measurement in systems of this type.