Initiation of homogeneous combustion in a high-velocity jet by the joint exposure of optical and electric discharge

This paper describes an experimental study of combustion initiation in a supersonic flow of a hydrogen-air mixture under the simultaneous action of focused pulse-periodic $\mathrm{CO}_2$ laser radiation and an external electric field. Combustion in a supersonic jet is studied on the basis of data on the intrinsic glow of a flame at the radiation wavelengths of excited $\mathrm{OH}^*$ radicals. Mixture combustion initiation depends on the shape of electrodes and electrical signals. The flame that occupies the entire cross section of an air-fuel jet is observed only under the conditions of simultaneous action of laser radiation and an electric field. Thus, the combined use of optical and electrical discharges makes it possible to initiate combustion and stabilize the flame of a hydrogen-air mixture in a supersonic flow without mechanical stabilizers.