Abstract

A fast temperature measurement technique is described which is suitable for use in dynamic reacting gases, particularly in situations which involve hydrocarbon–air combustion. Temperature is determined from the relative intensity of a pair of fully resolved absorption lines probed with a rapid-tuning single-frequency laser. Demonstration of the technique using 300-μs scans across the R₁(7) and R₁(11) lines in the (0,0) band of the A²∑⁺ ← X²Π system of OH present in the postflame gases above a CH₄–air flat-flame burner is reported. Fluorescence monitoring of the absorption spectra was used to provide improved spatial resolution. Temperatures inferred from simultaneous absorption and fluorescence measurements showed good agreement with radiation-corrected thermocouple scans.

© 1988 Optical Society of America

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