Local entrainment velocity in a premixed turbulent annular jet flame

The local entrainment velocity of the enstrophy interfaces of a methane-air turbulent premixed turbulent annular jet flame stabilized on a bluff-body burner has been investigated using a high-fidelity flame-resolved three-dimensional simulation. The enstrophy (inner and outer) and the scalar interfa...

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Detalles Bibliográficos
Autores: Cifuentes, L., Kempf, A., Dopazo, C.
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2018
País:España
Institución:Universidad de Zaragoza
Repositorio:Zaguán. Repositorio Digital de la Universidad de Zaragoza
OAI Identifier:oai:zaguan.unizar.es:79697
Acceso en línea:http://zaguan.unizar.es/record/79697
Access Level:acceso abierto
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spelling Local entrainment velocity in a premixed turbulent annular jet flameCifuentes, L.Kempf, A.Dopazo, C.The local entrainment velocity of the enstrophy interfaces of a methane-air turbulent premixed turbulent annular jet flame stabilized on a bluff-body burner has been investigated using a high-fidelity flame-resolved three-dimensional simulation. The enstrophy (inner and outer) and the scalar interfaces have been defined and characterized by their propagation speeds, VE and Sd , relative to the fluid flow. Mean values (<. Sd |. c> and <. VE |. c>) conditioned on the reaction progress variable c have been obtained. A thin layer (near the enstrophy interfaces) has been used to compute mean values (<. VE |. E>, <. Sd |. E>, and its different contributions) conditional upon enstrophy E. At the inner interface, results indicate that <. Sd |. c< &gt; 0 and >. Sd |. E> &gt; 0 (entrainment of fresh reactants into the flame front and hot products), while <. VE |. c> &lt; 0 and <. VE |. E> &lt; 0 (entrainment of hot products into the reacting jet across the inner enstrophy interface). The outer enstrophy interface displays <. VE |. E> &gt; 0 (ambient gases are predominantly entrained into the jet of reactants), which implies a lean mixture in its neighborhood. These preliminary results aim at understanding the physical mechanisms of flame anchoring, in terms of entrainments of either hot products or fresh reactants into the diffusive-reactive region. Local geometries of the inner and outer interfaces have also been examined, through the computation of joint probability density functions of the mean curvature km and Gauss curvature kg of the iso-enstrophy surfaces, and through <. VE >|. km, kg at the inner and outer interfaces. This information has subsequently been used to discuss the physics of how the turbulent entrainment process affects premixed flames.2018info:eu-repo/semantics/articleinfo:eu-repo/semantics/acceptedVersionapplication/pdfhttp://zaguan.unizar.es/record/79697reponame:Zaguán. Repositorio Digital de la Universidad de Zaragozainstname:Universidad de ZaragozaInglésinfo:eu-repo/grantAgreement/EC/H2020/706672This project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No H2020 706672-ITPFinfo:eu-repo/semantics/openAccessoai:zaguan.unizar.es:796972026-05-29T13:59:51Z
dc.title.none.fl_str_mv Local entrainment velocity in a premixed turbulent annular jet flame
title Local entrainment velocity in a premixed turbulent annular jet flame
spellingShingle Local entrainment velocity in a premixed turbulent annular jet flame
Cifuentes, L.
title_short Local entrainment velocity in a premixed turbulent annular jet flame
title_full Local entrainment velocity in a premixed turbulent annular jet flame
title_fullStr Local entrainment velocity in a premixed turbulent annular jet flame
title_full_unstemmed Local entrainment velocity in a premixed turbulent annular jet flame
title_sort Local entrainment velocity in a premixed turbulent annular jet flame
dc.creator.none.fl_str_mv Cifuentes, L.
Kempf, A.
Dopazo, C.
author Cifuentes, L.
author_facet Cifuentes, L.
Kempf, A.
Dopazo, C.
author_role author
author2 Kempf, A.
Dopazo, C.
author2_role author
author
description The local entrainment velocity of the enstrophy interfaces of a methane-air turbulent premixed turbulent annular jet flame stabilized on a bluff-body burner has been investigated using a high-fidelity flame-resolved three-dimensional simulation. The enstrophy (inner and outer) and the scalar interfaces have been defined and characterized by their propagation speeds, VE and Sd , relative to the fluid flow. Mean values (<. Sd |. c> and <. VE |. c>) conditioned on the reaction progress variable c have been obtained. A thin layer (near the enstrophy interfaces) has been used to compute mean values (<. VE |. E>, <. Sd |. E>, and its different contributions) conditional upon enstrophy E. At the inner interface, results indicate that <. Sd |. c< &gt; 0 and >. Sd |. E> &gt; 0 (entrainment of fresh reactants into the flame front and hot products), while <. VE |. c> &lt; 0 and <. VE |. E> &lt; 0 (entrainment of hot products into the reacting jet across the inner enstrophy interface). The outer enstrophy interface displays <. VE |. E> &gt; 0 (ambient gases are predominantly entrained into the jet of reactants), which implies a lean mixture in its neighborhood. These preliminary results aim at understanding the physical mechanisms of flame anchoring, in terms of entrainments of either hot products or fresh reactants into the diffusive-reactive region. Local geometries of the inner and outer interfaces have also been examined, through the computation of joint probability density functions of the mean curvature km and Gauss curvature kg of the iso-enstrophy surfaces, and through <. VE >|. km, kg at the inner and outer interfaces. This information has subsequently been used to discuss the physics of how the turbulent entrainment process affects premixed flames.
publishDate 2018
dc.date.none.fl_str_mv 2018
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
format article
status_str acceptedVersion
dc.identifier.none.fl_str_mv http://zaguan.unizar.es/record/79697
url http://zaguan.unizar.es/record/79697
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv info:eu-repo/grantAgreement/EC/H2020/706672
This project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No H2020 706672-ITPF
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv
publisher.none.fl_str_mv
dc.source.none.fl_str_mv reponame:Zaguán. Repositorio Digital de la Universidad de Zaragoza
instname:Universidad de Zaragoza
instname_str Universidad de Zaragoza
reponame_str Zaguán. Repositorio Digital de la Universidad de Zaragoza
collection Zaguán. Repositorio Digital de la Universidad de Zaragoza
repository.name.fl_str_mv
repository.mail.fl_str_mv
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