Temperature measurements in a Bunsen flame by planar laser-induced fluorescence

The article presents the results of measuring the temperature distribution parameters based on planar laser-induced fluorescence (PLIF) of the hydroxyl radical (OH) upon excitation of the transition (1-0) of the A(2)Sigma(+) - X-2 Pi system. Thermometry is based on registration of the ratio of the radiation intensity of the transition (2-0) and transitions (0-0), (1-1). For the most frequent excitation lines Q(2)(7), Q(1)(8), R-1(14), P-1(2), numerical simulation of fluorescence spectra was performed using the LASKIN software. In this work, the measurement procedure for the laminar pre-mixed Bunsen flame of a methane-air mixture was experimentally worked out. It was shown that the maximum sensitivity of the signal to temperature changes is achieved when the Q(1)(8) transition is excited. It was found that quenching of fluorescence has a negligible effect on the accuracy of temperature measurement.