Authors: Kuijun Wu Faquan Li Xuewu Cheng Yong Yang Xin Lin Yuan Xia
Publish Date: 2014/06/21
Volume: 117, Issue: 2, Pages: 659-666
Abstract
Midinfrared quantumcascade laser QCL absorption spectroscopy of CO2 near 42 μm has been developed for measurement of temperature and concentration in hot gases With stronger absorption linestrengths than transitions near 15 20 and 27 μm used previously the fundamental band 0001–0000 of CO2 near 42 μm provides greatly enhanced sensitivity and accuracy to sense CO2 in hightemperature gases Line R74 and line R96 are chosen as optimum pair for sensitive temperature measurements due to their hightemperature sensitivity equal signaltonoise ratio SNR weak interference of H2O transitions as well as relatively strong linestrengths in high temperature and weak absorption in room temperature The highresolution absorption spectrum of the far wings of the Rbranch R56–R100 in the fundamental vibrational band of CO2 is measured in a heated cell over the range 2384–2396 cm−1 at different temperatures from 700 to 1200 K Taking three factors into consideration including SNR concentration detectability and uncertainty sensitivity the absorption line R74 is selected to calculate CO2 concentration The tunable QCL absorption sensor is validated in mixtures of CO2 and N2 in a static cell for temperature range of 700–1200 K achieving an accuracy of ±6 K for temperature and ±5 for concentration measurements
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