Measurement of CH₄/AIR flame parameters by combination of laser induced polarization spectroscopy/laser induced fluorescence techniques

Laser induced polarization spectroscopy (LIPS) and laser induced fluorescence (LIF) measurement techniques have been employed simultaneously to diagnose CH4/AIR flame. Fluorescence spectra and polarization spectra of OH were measured at different height in the center of CH4/AIR flame at the same time, and the distributions of temperature and OH number density were obtained. The collection efficiency of fluorescence affected by the surface of the burner was analysed, the experimental data obtained by two techniques were compared, and OH number density distribution law along the height direction was acquired. The experimental results indicate the feasibility of combining these two techniques for combustion diagnostics, and the experimental data acquired by the two techniques agree well with each other, with a discrepancy within 5% for OH density and a discrepancy within 8% for temperature.