Abstract

Expressions for the rotationally relaxed population densities, under steady state laser excitation, have been derived with particular concern to the temperature measurement in flames. Agreement has been found between the developed theory and the measured rotational distribution. The experiments were carried out with both a flash lamp dye laser (long pulses) and a nitrogen laser-pumped dye laser (short pulses). The two distributions were found identical, showing that fast collisional rate constants are involved in the relaxation of the OH radical in a methane-air flame. The thermally assisted fluorescence technique has been proved to give reliable results in combustion diagnostics.

OH rotational temperature from two-line laser-excited fluorescence

Robert Cattolica
Appl. Opt. 20(7) 1156-1166 (1981)

Spatially resolved saturated absorption measurements of OH in methane-air flames

Giorgio Zizak, Francesco Cignoli, and Sergio Benecchi
Appl. Opt. 26(19) 4293-4297 (1987)

Measurement of OH rotational temperatures in a flame using degenerate four-wave mixing

Thomas Dreier and David J. Rakestraw
Opt. Lett. 15(1) 72-74 (1990)

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

Robert P. Lucht, Normand M. Laurendeau, and Donald W. Sweeney
Appl. Opt. 21(20) 3729-3735 (1982)

Photoacoustic detection of OH molecules in a methane–air flame

A. Rose, J. D. Pyrum, G. J. Salamo, and R. Gupta
Appl. Opt. 23(10) 1573-1579 (1984)