Measurement of carbon monoxide concentration at high-pressure by cavity enhanced absorption spectroscopy at 2.3um

CO is an important process product of hydrocarbon fuel combustion, and its concentration can represent the combustion reaction process of hydrocarbon fuel in scramjet combustion chamber, which always generate the flow field with high pressure and temperature. In this paper, CO concentration measurement under high pressure was studied. The absorption line near 2.3um was selected and the detection limit of CO concentration was improved by cavity enhanced absorption spectroscopy. A resonator for high pressure measurement was designed and developed, based on which, the CO concentration measurement experiments under different pressures were carried out, and the linear relationship between the absorption line width and the pressure was verified. The lower detection limit of CO concentration of the measurement system was 34ppm at 100kPa, and 225ppm at 500kPa.