Vis enkel innførsel

dc.contributor.authorGruber, Andrea
dc.contributor.authorRichardson, Edward S.
dc.contributor.authorAditya, Konduri
dc.contributor.authorChen, Jacqueline H.
dc.date.accessioned2019-02-15T10:23:44Z
dc.date.available2019-02-15T10:23:44Z
dc.date.created2018-11-22T10:13:09Z
dc.date.issued2018
dc.identifier.issn2469-990X
dc.identifier.urihttp://hdl.handle.net/11250/2585678
dc.description.abstractDirect numerical simulations are performed to investigate the transient upstream flame propagation (flashback) through homogeneous and fuel-stratified hydrogen-air mixtures transported in fully developed turbulent channel flows. Results indicate that, for both cases, the flame maintains steady propagation against the bulk flow direction, and the global flame shape and the local flame characteristics are both affected by the occurrence of fuel stratification. Globally, the mean flame shape undergoes an abrupt change when the approaching reactants transition from an homogeneous to a stratified mixing configuration. A V-shaped flame surface, whose leading-edge is located in the near-wall region, characterizes the nonstratified, homogeneous mixture case, while a U-shaped flame surface, whose leading edge propagates upstream at the channel centerline, distinguishes the case with fuel stratification (fuel-lean in the near-wall region and fuel-rich away from the wall). The characteristic thickness, wrinkling, and displacement speed of the turbulent flame brush are subject to considerable changes across the channel due to the dependence of the turbulence and mixture properties on the distance from the channel walls. More specifically, the flame transitions from a moderately wrinkled, thin-flamelet combustion regime in the homogeneous mixture case to a strongly wrinkled flame brush more representative of a thickened-flame combustion regime in the near-wall region of the fuel-stratified case. The combustion regime may be related to the Karlovitz number, and it is shown that a nominal channel-flow Karlovitz number, Kach in , based on the wall-normal variation of canonical turbulence (tη = (ν/ ) 1/2) and chemistry (tl = δl/Sl) timescales in fully developed channel flow, compares well with an effective Karlovitz number, Kach fl , extracted from the present DNS datasets using conditionally sampled values of tη and tl in the immediate vicinity of the flame (0.1nb_NO
dc.language.isoengnb_NO
dc.publisherAmerican Physical Societynb_NO
dc.titleDirect numerical simulations of premixed and stratified flame propagation in turbulent channel flownb_NO
dc.title.alternativeDirect numerical simulations of premixed and stratified flame propagation in turbulent channel flownb_NO
dc.typeJournal articlenb_NO
dc.typePeer reviewednb_NO
dc.description.versionpublishedVersionnb_NO
dc.source.volume3nb_NO
dc.source.journalPhysical Review Fluidsnb_NO
dc.source.issue11nb_NO
dc.identifier.doi10.1103/PhysRevFluids.3.110507
dc.identifier.cristin1633614
dc.relation.projectNorges forskningsråd: 193816nb_NO
dc.description.localcode© 2018 American Physical Societynb_NO
cristin.unitcode194,64,25,0
cristin.unitnameInstitutt for energi- og prosessteknikk
cristin.ispublishedtrue
cristin.fulltextpostprint
cristin.qualitycode1


Tilhørende fil(er)

Thumbnail

Denne innførselen finnes i følgende samling(er)

Vis enkel innførsel