A computational study of syngas auto-ignition characteristics at high-pressure and low-temperature conditions with thermal inhomogeneities

Handle URI:
http://hdl.handle.net/10754/594067
Title:
A computational study of syngas auto-ignition characteristics at high-pressure and low-temperature conditions with thermal inhomogeneities
Authors:
Pal, Pinaki; Mansfield, Andrew B.; Arias, Paul G.; Wooldridge, Margaret S.; Im, Hong G. ( 0000-0001-7080-1266 )
Abstract:
A computational study was conducted to investigate the characteristics of auto-ignition in a syngas mixture at high-pressure and low-temperature conditions in the presence of thermal inhomogeneities. Highly resolved one-dimensional numerical simulations incorporating detailed chemistry and transport were performed. The temperature inhomogeneities were represented by a global sinusoidal temperature profile and a local Gaussian temperature spike (hot spot). Reaction front speed and front Damköhler number analyses were employed to characterise the propagating ignition front. In the presence of a global temperature gradient, the ignition behaviour shifted from spontaneous propagation (strong) to deflagrative (weak), as the initial mean temperature of the reactant mixture was lowered. A predictive Zel'dovich–Sankaran criterion to determine the transition from strong to weak ignition was validated for different parametric sets. At sufficiently low temperatures, the strong ignition regime was recovered due to faster passive scalar dissipation of the imposed thermal fluctuations relative to the reaction timescale, which was quantified by the mixing Damköhler number. In the presence of local hot spots, only deflagrative fronts were observed. However, the fraction of the reactant mixture consumed by the propagating front was found to increase as the initial mean temperature was lowered, thereby leading to more enhanced compression-heating of the end-gas. Passive scalar mixing was not found to be important for the hot spot cases considered. The parametric study confirmed that the relative magnitude of the Sankaran number translates accurately to the quantitative strength of the deflagration front in the overall ignition advancement. © 2015 Taylor & Francis
KAUST Department:
Clean Combustion Research Center
Citation:
Pal P, Mansfield AB, Arias PG, Wooldridge MS, Im HG (2015) A computational study of syngas auto-ignition characteristics at high-pressure and low-temperature conditions with thermal inhomogeneities. Combustion Theory and Modelling 19: 587–601. Available: http://dx.doi.org/10.1080/13647830.2015.1068373.
Publisher:
Informa UK Limited
Journal:
Combustion Theory and Modelling
Issue Date:
30-Jul-2015
DOI:
10.1080/13647830.2015.1068373
Type:
Article
ISSN:
1364-7830; 1741-3559
Sponsors:
US Department of Energy via the National Energy Technology Laboratory[DE-FE0007465]
Appears in Collections:
Articles; Clean Combustion Research Center

Full metadata record

DC FieldValue Language
dc.contributor.authorPal, Pinakien
dc.contributor.authorMansfield, Andrew B.en
dc.contributor.authorArias, Paul G.en
dc.contributor.authorWooldridge, Margaret S.en
dc.contributor.authorIm, Hong G.en
dc.date.accessioned2016-01-19T13:20:45Zen
dc.date.available2016-01-19T13:20:45Zen
dc.date.issued2015-07-30en
dc.identifier.citationPal P, Mansfield AB, Arias PG, Wooldridge MS, Im HG (2015) A computational study of syngas auto-ignition characteristics at high-pressure and low-temperature conditions with thermal inhomogeneities. Combustion Theory and Modelling 19: 587–601. Available: http://dx.doi.org/10.1080/13647830.2015.1068373.en
dc.identifier.issn1364-7830en
dc.identifier.issn1741-3559en
dc.identifier.doi10.1080/13647830.2015.1068373en
dc.identifier.urihttp://hdl.handle.net/10754/594067en
dc.description.abstractA computational study was conducted to investigate the characteristics of auto-ignition in a syngas mixture at high-pressure and low-temperature conditions in the presence of thermal inhomogeneities. Highly resolved one-dimensional numerical simulations incorporating detailed chemistry and transport were performed. The temperature inhomogeneities were represented by a global sinusoidal temperature profile and a local Gaussian temperature spike (hot spot). Reaction front speed and front Damköhler number analyses were employed to characterise the propagating ignition front. In the presence of a global temperature gradient, the ignition behaviour shifted from spontaneous propagation (strong) to deflagrative (weak), as the initial mean temperature of the reactant mixture was lowered. A predictive Zel'dovich–Sankaran criterion to determine the transition from strong to weak ignition was validated for different parametric sets. At sufficiently low temperatures, the strong ignition regime was recovered due to faster passive scalar dissipation of the imposed thermal fluctuations relative to the reaction timescale, which was quantified by the mixing Damköhler number. In the presence of local hot spots, only deflagrative fronts were observed. However, the fraction of the reactant mixture consumed by the propagating front was found to increase as the initial mean temperature was lowered, thereby leading to more enhanced compression-heating of the end-gas. Passive scalar mixing was not found to be important for the hot spot cases considered. The parametric study confirmed that the relative magnitude of the Sankaran number translates accurately to the quantitative strength of the deflagration front in the overall ignition advancement. © 2015 Taylor & Francisen
dc.description.sponsorshipUS Department of Energy via the National Energy Technology Laboratory[DE-FE0007465]en
dc.publisherInforma UK Limiteden
dc.subjectauto-ignitionen
dc.subjectflamesen
dc.subjectignition regimesen
dc.subjectnumerical simulationen
dc.subjectsyngasen
dc.titleA computational study of syngas auto-ignition characteristics at high-pressure and low-temperature conditions with thermal inhomogeneitiesen
dc.typeArticleen
dc.contributor.departmentClean Combustion Research Centeren
dc.identifier.journalCombustion Theory and Modellingen
dc.contributor.institutionDepartment of Mechanical Engineering, University of Michigan, Ann Arbor, USAen
dc.contributor.institutionDepartment of Aerospace Engineering, University of Michigan, Ann Arbor, USAen
kaust.authorArias, Paul G.en
kaust.authorIm, Hong G.en
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