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Temperature measurement by two-line laser-saturated OH fluorescence in flames

1982; Optica Publishing Group; Volume: 21; Issue: 20 Linguagem: Inglês

10.1364/ao.21.003729

0003-6935

Robert P. Lucht, Normand M. Laurendeau, Donald W. Sweeney,

Laser Design and Applications

A technique is proposed and demonstrated for measuring combustion temperatures using two-line laser-saturated fluorescence. The rotational temperature of OH is determined by saturating two different rotational transitions in the (0,0) band of the A(2)Sigma(+)-X(2)II electronic system and detecting fluorescence emission which originates from the laser-pumped upper rotational levels. Temperature is calculated from the ratio of the fluorescence intensities for the two different excitation-emission pairs. The method is demonstrated by measuring temperature profiles in subatmospheric H(2)/O(2)/Ar flat flames. Temperatures measured by two-line saturated fluorescence are compared with temperatures measured by coated thermocouples and OH absorption and with predictions from an elementary chemical kinetics code. The temperatures measured by the two-line fluorescence technique are accurate to 3-5% and exhibit low random error.