Characteristics of premixed flames stabilized in an axisymmetric curved-wall jet burner with tip modification

Handle URI:
http://hdl.handle.net/10754/561442
Title:
Characteristics of premixed flames stabilized in an axisymmetric curved-wall jet burner with tip modification
Authors:
Kim, Daejoong; Gil, Y. S.; Chung, TaeWon; Chung, Suk-Ho ( 0000-0001-8782-312X )
Abstract:
The stabilization characteristics of premixed flames in an axisymmetric curved-wall jet burner have been experimentally investigated. This burner utilized the Coanda effect on top of a burner tip. The initially spherical burner tip was modified to a flat tip and a concave tip in order to improve flame stabilization by providing enough space for flow recirculation above the burner tip region. The flow characteristics have been visualized using a schlieren technique. Small-scale turbulence structure has been observed mainly in the interaction jet region (located downstream of the recirculation region) for large jet velocity (Reynolds number >11,500). An appreciable amount of air entrainment was exhibited from the half-angle of the jet spread, approximately 20. The averaged planar laser-induced fluorescence images of the flames for this large velocity demonstrated that the strong signal of OH radicals, representing reaction zones, existed in the recirculation zone, while it was weak in the interaction jet region due to intermittency and local extinction by the generation of small scale turbulence. The OH radical signals strengthened again in the merged jet region (downstream of the interaction jet region). In extreme cases of Reynolds number over 19,000, a unique flame exhibiting OH radicals only in the recirculation zone was observed for the concave tip. The flame stabilization has been mapped by varying jet velocity and equivalence ratio, and the result showed that the stabilization characteristics were improved appreciably from the initial spherical tip design, especially for rich mixtures. The flow fields measured by a laser Doppler velocimetry confirmed the existence of recirculation zone and the expansion of the recirculation zones for the modified tips. The temperature profile measured by a coherent anti-Stokes Raman spectroscopy exhibited an intermittent nature, especially near the recirculation zone.
KAUST Department:
Clean Combustion Research Center; Physical Sciences and Engineering (PSE) Division; Mechanical Engineering Program; Combustion and Laser Diagnostics Laboratory
Publisher:
Informa UK Limited
Journal:
Combustion Science and Technology
Issue Date:
10-Nov-2009
DOI:
10.1080/00102200903388091
Type:
Article
ISSN:
00102202
Sponsors:
D. K. acknowledges the support by Sogang University Research Grant 200810026.
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Mechanical Engineering Program; Clean Combustion Research Center

Full metadata record

DC FieldValue Language
dc.contributor.authorKim, Daejoongen
dc.contributor.authorGil, Y. S.en
dc.contributor.authorChung, TaeWonen
dc.contributor.authorChung, Suk-Hoen
dc.date.accessioned2015-08-02T09:11:25Zen
dc.date.available2015-08-02T09:11:25Zen
dc.date.issued2009-11-10en
dc.identifier.issn00102202en
dc.identifier.doi10.1080/00102200903388091en
dc.identifier.urihttp://hdl.handle.net/10754/561442en
dc.description.abstractThe stabilization characteristics of premixed flames in an axisymmetric curved-wall jet burner have been experimentally investigated. This burner utilized the Coanda effect on top of a burner tip. The initially spherical burner tip was modified to a flat tip and a concave tip in order to improve flame stabilization by providing enough space for flow recirculation above the burner tip region. The flow characteristics have been visualized using a schlieren technique. Small-scale turbulence structure has been observed mainly in the interaction jet region (located downstream of the recirculation region) for large jet velocity (Reynolds number >11,500). An appreciable amount of air entrainment was exhibited from the half-angle of the jet spread, approximately 20. The averaged planar laser-induced fluorescence images of the flames for this large velocity demonstrated that the strong signal of OH radicals, representing reaction zones, existed in the recirculation zone, while it was weak in the interaction jet region due to intermittency and local extinction by the generation of small scale turbulence. The OH radical signals strengthened again in the merged jet region (downstream of the interaction jet region). In extreme cases of Reynolds number over 19,000, a unique flame exhibiting OH radicals only in the recirculation zone was observed for the concave tip. The flame stabilization has been mapped by varying jet velocity and equivalence ratio, and the result showed that the stabilization characteristics were improved appreciably from the initial spherical tip design, especially for rich mixtures. The flow fields measured by a laser Doppler velocimetry confirmed the existence of recirculation zone and the expansion of the recirculation zones for the modified tips. The temperature profile measured by a coherent anti-Stokes Raman spectroscopy exhibited an intermittent nature, especially near the recirculation zone.en
dc.description.sponsorshipD. K. acknowledges the support by Sogang University Research Grant 200810026.en
dc.publisherInforma UK Limiteden
dc.subjectCoanda effecten
dc.subjectFlame stabilizationen
dc.subjectJet burneren
dc.titleCharacteristics of premixed flames stabilized in an axisymmetric curved-wall jet burner with tip modificationen
dc.typeArticleen
dc.contributor.departmentClean Combustion Research Centeren
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentMechanical Engineering Programen
dc.contributor.departmentCombustion and Laser Diagnostics Laboratoryen
dc.identifier.journalCombustion Science and Technologyen
dc.contributor.institutionDepartment of Mechanical Engineering, Sogang University, Seoul 121-742, South Koreaen
dc.contributor.institutionIndustry Partnership Institute, Inha University, Incheon, South Koreaen
dc.contributor.institutionSchool of Mechanical Engineering, Seoul National University, Seoul, South Koreaen
kaust.authorChung, Suk-Hoen
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