Influence of Flame Suppressants on the Level of Nonequilibrium Radiation during Ignition of Hydrogen-Oxygen Mixtures behind Shock Waves

Abstract

The nonequilibrium radiation occurring during ignition of a 10% stoichiometric hydrogen-oxygen mixture with flame suppressant additives diluted with argon behind shock waves was studied. Instead of the expected reduction in the super-equilibrium radiation of active radicals in the ignition zone, the addition of halogenated flame suppressants led to increased UV radiation around wavelengths of 220 and 411 nm characteristic of the HO₂ radical and H₂O₂ and H₂O molecules. Therefore, the hypothesis about the suppression mechanism due to quenching of the excited HO^*₂ radical is not confirmed, and the effect of flame-suppressing additives is due to the binding of H and O atoms.