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Show Tk-1. LASER DETERMINATION OF CHEMICALLY ACTIVE FREE RADICALS IN FLAMES David R. Crosley, Gregory P. Smith, and Jay B. Jeffries Molecular Physics Laboratory SRI International Menlo Park, California 94025 U SA ABSTRACT An understanding of flame chemistry is a necessary part of designing and optimizing burners to meet environmental regulations while maintaining system efficiency. W e have performed quantitative, absolute concentration measurements for several free radicals to test various aspects of the predictive capabilities of GRI-Mech, the chemical mechanism for natural gas combustion. The C H , N O , O H , and H C O radicals were studied in a series of low pressure methane/02/N2 flames using the technique of laser-induced fluorescence. The results show that GRI-Mech predicts well the hydrocarbon oxidation chemistry in lean and near stoichiometric flames, but appears to have some inadequacies for rich flames. The rate coefficient for the important C H + N 2 reaction in the current version of GRI-Mech appears to be too low. Finally, reburn of N O is correctly predicted for a lean flame but not a rich one. 1 |
