On Ignition of Dust Particles in Hot Stagnant Oxygen Gas

Abstract
To investigate the ignition delay of dust particles in hot stagnant oxygen gas. reflected shock waves have been created in a horizontal shock tube. By using a newly designed air injector, very well-distributed cloud formation of various dusts could be obtained. The proper hot stagnant gas conditions were generated by placing a reflector 1.5 cm behind the air injector. The post-reflected shock gas temperature of 1200-1600 K could be obtained by reflecting the incident shock waves in the range of Mach number 2.8-3.3. Experimentally the ignition delay was defined as the time interval between the arrival of a reflected shock wave at dusts and the detection of visible light. Measured ignition delays of various dusts investigated were located lower than 1 msec under the given conditions. These values are one order higher than those measured in the incident shock wave conditions where a strong gas flow around particles enchances the ignition of particles.

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