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Autoignition and early flame behavior of a spherical cluster of 49 monodispersed droplets

Authors :
Shinji Nakaya
Toshikazu Kadota
Maki Yoshida
Daisuke Segawa
Source :
Proceedings of the Combustion Institute. 31:2149-2156
Publication Year :
2007
Publisher :
Elsevier BV, 2007.

Abstract

Autoignition and early flame behavior of a spherical cluster of 49 monodispersed droplets in a high-temperature air were examined in microgravity. The monodispersed suspended-droplet cluster (MSDC) model with which both droplet spacing and initial droplet diameter were well-controlled was developed, and the solidified-fuel fiber-suspension technique was utilized for making the MSDC model. The tested 3D MSDC models had the HCP (hexagonal closest packing) structure. Individual flames, which enveloped each droplet, or group flame, which enveloped the whole droplet cluster, were formed immediately after ignition. The flame changed from the group flame to a cluster of the individual flames either with increasing the droplet spacing or decreasing the initial droplet diameter. Each of the individual flames merged into the group flame with the lapse of time. Burning sphere diameter decreased at the beginning, and then increased. The transition from the individual flames to the group flame occurred around the time period at which the burning sphere diameter reached its minimum. The time period at which the burning sphere diameter reached its maximum was delayed and the expansion rate of the burning sphere was enhanced with decreasing the droplet spacing or with increasing the initial droplet diameter.

Details

ISSN :
15407489
Volume :
31
Database :
OpenAIRE
Journal :
Proceedings of the Combustion Institute
Accession number :
edsair.doi...........cca3d59106b8f9ffde60a1f2eabb6461
Full Text :
https://doi.org/10.1016/j.proci.2006.07.124