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ISSN Print: 1044-5110
ISSN Online: 1936-2684
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Dynamic Primary Atomization Characteristics in an Airblast Atomizer, High Pressure Conditions
ABSTRACT
The primary atomization was studied experimentally for several flow configurations, in a planar airblast atomizer. The liquid sheet injected had a 300μm thickness. The employed techniques were Laser Oscillometry, LDV-PDI, PIV and flow visualization via fast camera. In the liquid flow, the momentum flux was varied by injecting both water and kerosene JET A1 at several velocities. Conversely, the airflow momentum flux was modified by adjusting both its velocity and absolute pressure. The latter parameter reached a value of 11bar. The atomization mechanisms described in the literature at standard conditions, were observed at the high pressure environments, as long as, the momentum flux ratio, M, remained constant. Furthermore, a new atomization mechanism was observed for values of M beyond 20. This regime was referred as membrane break-up due to the predominant structures observed. The results presented in this manuscript correspond to characteristics related to the sheets's motion: The global oscillation frequency, the wave velocity gradient in the intact sheet region and the sauter mean diameter far from the injector lips. Furthermore, these variables displayed a weak change both in magnitude and behaviour with the changes in atomization mechanisms. A set of empirical relations are provided to link these characteristics witht the flow conditions.
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Jaberi A., Tadjfar M., Visualization of two-dimensional liquid sheets issued into subsonic gaseous crossflow, Journal of Visualization, 23, 4, 2020. Crossref