Measurement of temperature and concentration of OH radicals in combustion of hydrogen and ethanol by the laser-induced fluorescence technique

Diffusion combustion of ethanol and hydrogen and homogeneous combustion of hydrogen–oxygen mixtures are studied by the laser-induced fluorescence technique in the linear regime and with signal saturation. Data on the flame temperature and OH concentration are obtained. The burning temperature of 3090 K for a stoichiometric O$_2$–H$_2$ mixture is in agreement with the known value. It is shown that the maximum concentrations of radicals in the hydrogen–air and stoichiometric hydrogen–oxygen flames are close to each other (4.4 $\cdot$ 10$^{16}$ cm$^{-3}$).