Spectral Emissivities and Integrated Intensities of the 27- μ CO_2 Band between 1200° and 1800°K*

Abstract

Spectral emissivities have been obtained for the 2ν2+ν3 and ν3+ν1 carbon dioxide combination bands between 3100 and 3800 cm−1 at 1200°, 1500°, and 1800°K. Heated CO2 was produced in a 150-lb-thrust rocket burner burning gaseous carbon monoxide and oxygen. Emission measurements were made on the expanded exhaust gas of the burner where the composition, total pressure, and temperature could be defined. The spectral emissivities were determined from a calibrated emission spectrum and a spectroscopic determination of the temperature of the test gas. The hot CO2 samples were observed at a total pressure of 1 atm in the optically thin region where the highest spectral emissivities at 3700 cm−1 were about 0.1. The spectral emissivity curves were used to obtain the integrated intensity of the 2.7-μ CO2 band at the high temperatures. The variations of the spectral emissivities and integrated intensities with temperature agree with previous predictions.