DIFFUSION COMBUSTION OF HYDROGEN ROUND MICROJET AT SUB- AND SUPERSONIC VELOCITY EFFLUX FROM NOZZLE

Read more The purpose of this work is experimental study of the round hydrogen jets diffusion combustion efflux from nozzles with different diameters of nozzle exit at sub- and supersonic velocity. As a result of the experimental studies the following results are received. Four scenarios of diffusion combustion of the hydrogen round microjets, including «supersonic burning» in the presence of supersonic cells as by air, and on hydrogen are for the first time submitted. It is found that stabilization of the hydrogen round microjet subsonic burning is connected with existence of «bottleneck flame region», and «supersonic burning» of a microjet with existence of supersonic cells. Hysteresis of the hydrogen round microjets diffusion combustion is connected with the microjet ignition method of (near or far from a nozzle exit) and directions of the velocity change of its efflux (growth or reduction) is found. It is shown that «supersonic diffusion combustion» of the hydrogen round microjets as by air, and to hydrogen, is implemented only in a situation of the micronozzle diameter size outlet lying in the range of 1 mm.

Keywords:
hydrogen round microjet, diffusion combustion, «bottleneck flame region», mean velocity profile, «supersonic combustion», hysteresis, schlieren method, shadow patterns.
УДК 544.452.42

DIFFUSION COMBUSTION OF HYDROGEN ROUND MICROJET AT SUB- AND SUPERSONIC VELOCITY EFFLUX FROM NOZZLE