Grouping and trapping of evaporating droplets in an oscillating gas flow

Katoshevski, D., Shakked, T., Sazhin, S.S., Crua, C. and Heikal, M.R. (2008) Grouping and trapping of evaporating droplets in an oscillating gas flow International Journal of Heat and Fluid Flow, 29 (2). pp. 415-426. ISSN 0142-727X

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Abstract

A new approach to the analysis of droplet grouping in an oscillating gas flow is suggested. This is based on the investigation of droplet trajectories in the frame of reference moving with the phase velocity of the wave. Although the equations involved are relatively simple, the analysis shows distinctive characteristics of grouping and non-grouping cases. In the case of grouping, droplet trajectories converge to the points for which the ratio of flow velocity in this frame of reference and the amplitude of flow oscillations is less than 1, and the cosine of this ratio is positive. In the case of non-grouping, droplet trajectories in this frame of reference oscillate around the translational velocity close to the velocity of flow in the same frame of reference. The effect of the droplet size on the grouping pattern is investigated. It has been pointed out that for the smaller droplets much more stable grouping is observed. The effect of droplet evaporation is studied in the limiting case when the contribution of the heat-up period can be ignored. It is shown that evaporation can lead to droplet grouping even in the case when the non-evaporating droplets are not grouped. This is related to the reduction in droplets diameter during the evaporation process. Coupling between gas and droplets is shown to decrease the grouping tendency. A qualitative agreement between predictions of the model and in-house experimental observations referring to Diesel engine sprays has been demonstrated.

Item Type: Journal article
Additional Information: This is the author’s version of a work that was accepted for publication in International Journal of Heat and Fluid Flow. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in International Journal of Heat and Fluid Flow, 29, 2, 2008 10.1016/j.ijheatfluidflow.2007.10.003
Uncontrolled Keywords: spray; grouping; trapping; evaporation; coupled solution
Subjects: H000 Engineering > H300 Mechanical Engineering > H330 Automotive Engineering
DOI (a stable link to the resource): 10.1016/j.ijheatfluidflow.2007.10.003
Faculties: Faculty of Science and Engineering > School of Computing, Engineering and Mathematics > Engineering and Product Design Research > Automotive Engineering
Depositing User: Dr Cyril Crua
Date Deposited: 21 Nov 2007
Last Modified: 21 May 2014 11:01
URI: http://eprints.brighton.ac.uk/id/eprint/3159

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