Initiation of combustion of a hydrogen-air mixture with ozone impurity by UV laser radiation

The ignition kinetics of hydrogen-air mixtures with a small amount (0.5%) of ozone that are exposed to laser radiation with wavelength lambda(I) = 248.4 nm is analyzed. The formation of excited O(D-1) atoms and O-2(a(1)Delta(g)) molecules due to O-3 molecule photodissociation is shown to greatly intensify the chain reactions and noticeably decrease the induction period and ignition temperature compared with the case when the radiation is absent even if the radiation energy applied to the gas is low, E-s = 0.5-1.0 eV per O-3 molecule. The efficiency of such a way of combustion initiation is much higher than at local heating of the medium by laser radiation but, at the same time, is considerably lower than the efficiency of the method based on excitation of O-3 molecule asymmetric oscillations.