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dc.contributor.authorZhou, Zhen
dc.contributor.authorShoshin, Yuriy
dc.contributor.authorHernandez Perez, Francisco
dc.contributor.authorvan Oijen, Jeroen A.
dc.contributor.authorde Goey, Laurentius P.H.
dc.date.accessioned2018-03-22T05:00:12Z
dc.date.available2018-03-22T05:00:12Z
dc.date.issued2018-03-20
dc.identifier.citationZhou Z, Shoshin Y, Hernández-Pérez FE, van Oijen JA, de Goey LPH (2018) Formation and stabilization of multiple ball-like flames at Earth gravity. Combustion and Flame 192: 35–43. Available: http://dx.doi.org/10.1016/j.combustflame.2018.01.034.
dc.identifier.issn0010-2180
dc.identifier.doi10.1016/j.combustflame.2018.01.034
dc.identifier.urihttp://hdl.handle.net/10754/627375
dc.description.abstractNear-limit low-Lewis-number premixed flame behavior is studied experimentally and numerically for flames of H–CH–air mixtures that are located in a 55 mm diameter tube and below a perforated plate in a downward mixture flow. A combustion regime diagram is experimentally identified in terms of equivalence ratio and ratio of H to CH (variation of fuel Lewis number). Planar flames, cell-like flames, distorted cap-like flames, and arrays of ball-like flames are progressively observed in the experiments as the equivalence ratio is decreased. The experimentally observed ball-like lean limit flames experience chaotic motion, which is accompanied by sporadic events of flame splitting and extinction, while the total number of simultaneously burning flamelets remains approximately the same. In separate experiments, the multiple ball-like lean limit flames are stabilized by creating a slightly non-uniform mixture flow field. The CH* chemiluminescence distributions of the lean limit flames are recorded, showing that the ball-like lean limit flame front becomes more uniform in intensity and its shape approaches a spherical one with the increase of H content in the fuel. Numerical simulations are performed for single representative flames of the array of stabilized flamelets observed in the experiments. The simulated ball-like lean limit flame is further contrasted with the single ball-like flame that forms in a narrow tube (13.5 mm inner diameter) with an iso-thermal wall. The numerical results show that the ball-like lean limit flames present in the array of ball-like flames are more affected by the buoyancy-induced recirculation zone, compared with that in the narrow tube, revealing why the shape of the ball-like flame in the array deviates more from a spherical one. All in all, the wall confinement is not crucial for the formation of ball-like flames at terrestrial gravity.
dc.description.sponsorshipThe financial support of the Dutch Technology Foundation (STW), Project 13549, is gratefully acknowledged. The authors thank Prof. Clinton Groth for providing access to the CFFC (Computational Framework for Fluids and Combustion) code.
dc.publisherElsevier BV
dc.relation.urlhttps://www.sciencedirect.com/science/article/pii/S0010218018300385
dc.rightsNOTICE: this is the author’s version of a work that was accepted for publication in Combustion and Flame. 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 Combustion and Flame, [192, , (2018-03-20)] DOI: 10.1016/j.combustflame.2018.01.034 . © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
dc.subjectBall-like flame
dc.subjectHydrogen–methane
dc.subjectLean flammability limit
dc.subjectLow Lewis number
dc.titleFormation and stabilization of multiple ball-like flames at Earth gravity
dc.typeArticle
dc.contributor.departmentClean Combustion Research Center
dc.contributor.departmentPhysical Science and Engineering (PSE) Division
dc.identifier.journalCombustion and Flame
dc.eprint.versionPost-print
dc.contributor.institutionDepartment of Mechanical Engineering, Eindhoven University of Technology, 5600MB, Eindhoven, PO Box 513, , Netherlands
kaust.personHernandez Perez, Francisco
refterms.dateFOA2020-03-20T00:00:00Z
dc.date.published-online2018-03-20
dc.date.published-print2018-06


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