FEATURES OF THE DIFFUSION COMBUSTION OF HYDROGEN MICROJET AT VARIOUS SPATIAL ORIENTATION OF THE NOZZLE EXIT WITH TOP – HAT MEAN VELOCITY PROFILE AT THE NOZZLE EXIT

Read more The purpose of the given work will consist in the experimental studies of features diffusion combustion of a hydrogen round microjet, effusing from micronozzle with top – hat mean velocity profile at the nozzle exit, depending on spatial orientation of the nozzle exit. It is revealed, that in conditions of a jet velocity vector orientation towards terrestrial gravitation vector «g» (opposite or perpendicular) the basic characteristics of the flame evolution depending on gas consumption (Q) (or jet velocity U) are rather close to each other. To these characteristics concern such as ranges of the «bottleneck flame area» presence, flame separation at presence of the «bottleneck flame area», presence of the «bottleneck flame area» but absence of a turbulent jet combustion and finally ending of the microjet combustion. On the contrary, in situation of the hydrogen round microjet diffusion combustion in conditions of a jet velocity vector orientation towards terrestrial gravitation vector «g» (orientability – like) the basic characteristics of the flame evolution depending on a jet velocity are sharply differed from two previous cases. The range of existence of the «bottleneck flame area» is reduced, flame separation occurs in absence of the «bottleneck flame area», there is no situation of the «bottleneck flame area» combustion at turbulent flame separation and there is no situation of the «bottleneck flame area» combustion at burn termination of the turbulent part of a microjet and finally ending of the microjet combustion occurs at the much greater jet velocity.

Keywords:
hydrogen round microjet wth top – hat mean velocity profile at the nozzle exit, diffusion combustion, «bottleneck flame area», schlieren method, shadow patterns. 
УДК 544.452.42

FEATURES OF THE DIFFUSION COMBUSTION OF HYDROGEN MICROJETAT VARIOUS SPATIAL ORIENTATION OF THE NOZZLE EXIT WITH TOP – HAT MEAN VELOCITY PROFILE AT THE NOZZLE EXIT