Combustion of round hydrogen microjet in a cocurrent air flow

Experimental data on combustion of a round hydrogen microjet in a cocurrent coaxial air jet are presented. As is found, the combustion of microjet is dominated by the generation of “bottleneck-flame region” that is in agreement with our previous observations on the diffusion combustion of subsonic hydrogen microjets. Transformation of the spherical “bottleneck-flame region” to a cylindrical one is observed. At supersonic combustion of the round hydrogen microjet, supersonic cells are generated both in the microjet and in the cocurrent coaxial air flow. A feature of the combustion process is the flame lift-off from the nozzle exit.