ONE-DIMENSIONAL, TIME-RESOLVED RAMAN MEASUREMENTS IN A SOOTING FLAME MADE WITH 355-NM EXCITATION

Single-shot vibrational Raman measurements were performed along an 11- mm-long line crossing the reaction zone in a premixed, fuel-rich (phi = 10), laminar methane-air flame by use of a frequency-tripled Nd:YAG laser with a 355-nm emission wavelength. This laser source seems to ha ve advantages relative to KrF excimer lasers as well as to Nd:YAG lase rs at 532 nm for hydrocarbon combustion diagnostics. The Raman emissio ns of all major species (N-2, O-2, CH2, H-2, CO2, H2O) were detected s imultaneously with a spatial resolution of 0.4 mm. By integration over selected spectral intervals, the mole fractions of all species and su bsequently the local gas temperatures have been obtained. A comparison of the temperatures that were found with results from filtered Raylei gh experiments showed good agreement, indicating the success of what a re to the best of our knowledge the first one-dimensional single-shot Raman measurements in a sooting hydrocarbon flame. (C) 1998 Optical So ciety of America.