Flame Temperature Mapping Using Two Synthetic OH Planar Laser-Induced Fluorescence Images

This work presents a fully computational study of a synthetic two-line planar laser-induced fluorescence technique for non-intrusive temperature prediction in hydrogen-air flames, with relevance to combustion diagnostics and aerospace propulsion systems. Computational fluid dynamics and computational spectroscopy are used to generate synthetic fluorescence images for two excitation wavelengths, 282 nm and 307 nm, exciting hydroxyl radicals. Temperature fields are then retrieved from these images through numerical processing based on Boltzmann population distributions and fluorescence intensity ratios. Validation against the original computational fluid dynamic data using metrics such as mean absolute error, root mean square error, Pearson correlation coefficient, and coefficient of determination R^2 demonstrates reliable reconstruction of the flame temperature distributions. This purely numerical study establishes a foundation for experimental implementation and optimization of two-line OH fluorescence diagnostics in high-temperature reacting flows.