Hydrogen Microjet Research Articles

Structure Of The Attached Flame During Diffusion Hydrogen Microjet Combustion (Slotted Nozzle)

The purpose of this work is experimental study of diffusion combustion of the plane hydrogen microjet with different slotted nozzle dimensions. The new phenomenon is revealed during combustion of a plane hydrogen microjet, which we have named «bottleneck», as well as in a situation of a round microjet combustion. The special attention has been given to research of characteristics of the «bottleneck» development and its role during of a hydrogen plane microjet combustion. It is shown, that «bottleneck» represents the closed spherical area of the hydrogen with air mixture combustion in a jet near-field. The «bottleneck» area is closed by a powerful density gradient. It is found, that the laminar hydrogen jet in this area overcomes a density gradient of gas, becomes turbulent and combustion process is accompanied both a turbulent jet, and a turbulent flame further downstream evolution. It is shown, that the spatial size of a «bottleneck» decreases with growth of a jet velocity. It is found, that «bottleneck» does not arise in case of the big nozzle lengthening (l/h > 10)