The anchoring mechanism of a bluff-body stabilized laminar premixed flame

Handle URI:
http://hdl.handle.net/10754/599876
Title:
The anchoring mechanism of a bluff-body stabilized laminar premixed flame
Authors:
Kedia, Kushal S.; Ghoniem, Ahmed F.
Abstract:
The objective of this work is to investigate the mechanism of the laminar premixed flame anchoring near a heat-conducting bluff-body. We use unsteady, fully resolved, two-dimensional simulations with detailed chemical kinetics and species transport for methane-air combustion. No artificial flame anchoring boundary conditions were imposed. Simulations show a shear-layer stabilized flame just downstream of the bluff-body, with a recirculation zone formed by the products of combustion. A steel bluff-body resulted in a slightly larger recirculation zone than a ceramic bluff-body; the size of which grew as the equivalence ratio was decreased. A significant departure from the conventional two-zone flame-structure is shown in the anchoring region. In this region, the reaction zone is associated with a large negative energy convection (directed from products to reactants) resulting in a negative flame-displacement speed. It is shown that the premixed flame anchors at an immediate downstream location near the bluff-body where favorable ignition conditions are established; a region associated with (1) a sufficiently high temperature impacted by the conjugate heat exchange between the heat-conducting bluff-body and the hot reacting flow and (2) a locally maximum stoichiometry characterized by the preferential diffusion effects. © 2014 The Combustion Institute.
Citation:
Kedia KS, Ghoniem AF (2014) The anchoring mechanism of a bluff-body stabilized laminar premixed flame. Combustion and Flame 161: 2327–2339. Available: http://dx.doi.org/10.1016/j.combustflame.2014.02.005.
Publisher:
Elsevier BV
Journal:
Combustion and Flame
KAUST Grant Number:
KUS-11-010-01
Issue Date:
Sep-2014
DOI:
10.1016/j.combustflame.2014.02.005
Type:
Article
ISSN:
0010-2180
Sponsors:
This work was supported by King Abdullah University of Science and Technology (KAUST) award number KUS-11-010-01. We would like to acknowledge Dr. Habib Najm, Dr. Cosmin Safta and Dr. Jaideep Ray (Combustion Research Facility, Sandia National Laboratories, Livermore, CA, USA) for their major contribution towards the SAMR tool development.
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Publications Acknowledging KAUST Support

Full metadata record

DC FieldValue Language
dc.contributor.authorKedia, Kushal S.en
dc.contributor.authorGhoniem, Ahmed F.en
dc.date.accessioned2016-02-28T06:31:28Zen
dc.date.available2016-02-28T06:31:28Zen
dc.date.issued2014-09en
dc.identifier.citationKedia KS, Ghoniem AF (2014) The anchoring mechanism of a bluff-body stabilized laminar premixed flame. Combustion and Flame 161: 2327–2339. Available: http://dx.doi.org/10.1016/j.combustflame.2014.02.005.en
dc.identifier.issn0010-2180en
dc.identifier.doi10.1016/j.combustflame.2014.02.005en
dc.identifier.urihttp://hdl.handle.net/10754/599876en
dc.description.abstractThe objective of this work is to investigate the mechanism of the laminar premixed flame anchoring near a heat-conducting bluff-body. We use unsteady, fully resolved, two-dimensional simulations with detailed chemical kinetics and species transport for methane-air combustion. No artificial flame anchoring boundary conditions were imposed. Simulations show a shear-layer stabilized flame just downstream of the bluff-body, with a recirculation zone formed by the products of combustion. A steel bluff-body resulted in a slightly larger recirculation zone than a ceramic bluff-body; the size of which grew as the equivalence ratio was decreased. A significant departure from the conventional two-zone flame-structure is shown in the anchoring region. In this region, the reaction zone is associated with a large negative energy convection (directed from products to reactants) resulting in a negative flame-displacement speed. It is shown that the premixed flame anchors at an immediate downstream location near the bluff-body where favorable ignition conditions are established; a region associated with (1) a sufficiently high temperature impacted by the conjugate heat exchange between the heat-conducting bluff-body and the hot reacting flow and (2) a locally maximum stoichiometry characterized by the preferential diffusion effects. © 2014 The Combustion Institute.en
dc.description.sponsorshipThis work was supported by King Abdullah University of Science and Technology (KAUST) award number KUS-11-010-01. We would like to acknowledge Dr. Habib Najm, Dr. Cosmin Safta and Dr. Jaideep Ray (Combustion Research Facility, Sandia National Laboratories, Livermore, CA, USA) for their major contribution towards the SAMR tool development.en
dc.publisherElsevier BVen
dc.subjectBluff-bodyen
dc.subjectConjugate heat exchangeen
dc.subjectFlame structureen
dc.subjectLaminaren
dc.subjectPreferential diffusionen
dc.subjectPremixed flame anchoringen
dc.titleThe anchoring mechanism of a bluff-body stabilized laminar premixed flameen
dc.typeArticleen
dc.identifier.journalCombustion and Flameen
dc.contributor.institutionMassachusetts Institute of Technology, Cambridge, United Statesen
kaust.grant.numberKUS-11-010-01en
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