Multispecies Raman scattering combines with molecular fluorescence

Spontaneous Raman scattering, Rayleigh scattering, and laser-induced OH fluorescence are combined to perform simultaneous, single-shot, point measurements of major species concentrations, temperature, and hydroxyl radical concentration in turbulent flames. This combination of laser diagnostic techniques has proven to be a useful tool for the investigation of the effects of high turbulent mixing rates on the distribution of chemical states in nonpremixed jet flames. This paper outlines the experimental strategy for these multispecies measurements and reviews the various fuels and fuel combinations that have been investigated. Methods of conditional analysis of the multispecies data that allow direct evaluation of the deviation from equilibrium of certain important combustion reactions are described. As an example, results on deviations from equilibrium of the composite reaction 2OH=H₂+O₂ in a turbulent methane flame are presented.