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Numerical analyses of deflagration initiation by a hot jet

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dc.affiliation.dptoUC3M. Departamento de Ingeniería Térmica y de Fluidoses
dc.affiliation.grupoinvUC3M. Grupo de Investigación: Mecánica de Fluidoses
dc.contributor.authorIglesias Estradé, María Inmaculada
dc.contributor.authorVera Coello, Marcos
dc.contributor.authorSánchez Pérez, Antonio Luis
dc.contributor.authorLiñán Martínez, Amable
dc.date.accessioned2014-02-25T11:45:53Z
dc.date.available2014-02-25T11:45:53Z
dc.date.issued2012-08-07
dc.description.abstractNumerical simulations of axisymmetric reactive jets with one-step Arrhenius kinetics are used to investigate the problem of deflagration initiation in a premixed fuel–air mixture by the sudden discharge of a hot jet of its adiabatic reaction products. For the moderately large values of the jet Reynolds number considered in the computations, chemical reaction is seen to occur initially in the thin mixing layer that separates the hot products from the cold reactants. This mixing layer is wrapped around by the starting vortex, thereby enhancingmixing at the jet head, which is followed by an annular mixing layer that trails behind, connecting the leading vortex with the orifice rim. A successful deflagration is seen to develop for values of the orifice radius larger than a critical value aϲ in the order of the flame thickness of the planar deflagration δL. Introduction of appropriate scales provides the dimensionless formulation of the problem, with flame initiation characterised in terms of a critical Damk¨ohler number ∆ϲ = (aϲ/δL)², whose parametric dependence is investigated. The numerical computations reveal that, while the jet Reynolds number exerts a limited influence on the criticality conditions, the effect of the reactant diffusivity on ignition is much more pronounced, with the value of ∆ϲ increasing significantly with increasing Lewis numbers Le. The reactant diffusivity affects also the way ignition takes place, so that for reactants with Le ≳ 1 the flame develops as a result of ignition in the annular mixing layer surrounding the developing jet stem, whereas for highly diffusive reactants with Lewis numbers sufficiently smaller than unity combustion is initiated in the mixed core formed around the starting vortex. The analysis provides increased understanding of deflagration initiation processes, including the effects of differential diffusion, and points to the need for further investigations incorporating detailed chemistry models for specific fuel–air mixtures.en
dc.description.sponsorshipThis work was supported by the SpanishMCINN through project numbers ENE2008-06515-C01 and CSD2010-00010 and by the Comunidad de Madrid through project number S2009/ENE-1597.en
dc.format.extent17
dc.format.mimetypeapplication/pdf
dc.identifier.bibliographicCitationCombustion Theory and Modelling (2012), vol.16, n.6, pp.994-1010en
dc.identifier.doi10.1080/13647830.2012.690048
dc.identifier.issn1364-7830
dc.identifier.publicationfirstpage994
dc.identifier.publicationissue6
dc.identifier.publicationlastpage1010
dc.identifier.publicationtitleCombustion theory and modellingen
dc.identifier.publicationvolume16
dc.identifier.urihttps://hdl.handle.net/10016/18347
dc.identifier.uxxiAR/0000012667
dc.language.isoeng
dc.publisherTaylor & Francisen
dc.relation.projectIDComunidad de Madrid. S2009/ENE-1597/HYSYCOMBes
dc.relation.publisherversionhttp://dx.doi.org/10.1080/13647830.2012.690048
dc.rights© 2012 Taylor & Francises
dc.rights.accessRightsopen access
dc.subject.ecienciaFísicaes
dc.subject.ecienciaIngeniería Industriales
dc.subject.ecienciaQuímicaes
dc.subject.otherDeflagrationen
dc.subject.otherIgnitionen
dc.subject.otherTransient hot jeten
dc.subject.otherStarting vortexen
dc.subject.otherDifferential diffusionen
dc.titleNumerical analyses of deflagration initiation by a hot jeten
dc.typeresearch article*
dc.type.hasVersionAM*
dspace.entity.typePublication
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