Simultaneous Rayleigh scattering and laser-induced CH fluorescence for reaction zone imaging in high-speed premixed hydrocarbon flames

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/air flames where CH concentration is on the order of 1 ppm based on flamelet calculations. The present experimental conditions are also examined and shown to be suitable for quantitative measurements of CH radical based on the two-level model analysis. A linear relationship can be found between the measured CH signal intensity and the calculated CH concentration within a maximum 30% uncertainty range. The FWHM thickness of the CH profile in a stoichiometric laminar methane flame was shown to be less than 0.3 mm, which is the smallest ever achieved. Simultaneous image pairs of flame temperature and concentration of CH radicals from a premixed turbulent Bunsen flame at an exit velocity of 65 m/sec are obtained to demonstrate the system superiority of application on high-speed reacting flows.