Measurement of gas temperature profile using spectral intensity from CO 2 4.3 μm band

Abstract

Spectral remote sensing (SRS) method for determining the temperature profile along a line-of-sight is investigated experimentally. Quartz tube, within which combustion gas flows, is used as the test section. The inversion procedure is carried out with a line-by-line (LBL) method and a CK-based WNB model. The optimal gas temperature profile that minimizes the error between the measured narrow band intensities around the CO 2 4.3 μm band and the calculated ones is obtained as the result of the inversion process. The gas temperature is also measured with a shielded thermocouple and corrected for the error. The results show that the front, center and back temperatures are within errors of 1%, 4% and 12%, respectively. SRS technique shows poor performance in measuring cold gas temperatures behind a hot layer. The reconstructed temperature profile in the front region is, however, in good agreement with the thermocouple reading. The potential applicability of SRS is positively demonstrated and current technical limitations are also discussed.