On the controlling mechanism of the upper turnover states in the NTC regime

Handle URI:
http://hdl.handle.net/10754/596019
Title:
On the controlling mechanism of the upper turnover states in the NTC regime
Authors:
Ji, Weiqi; Zhao, Peng ( 0000-0002-6743-6269 ) ; He, Tanjin; He, Xin; Farooq, Aamir ( 0000-0001-5296-2197 ) ; Law, Chung K.
Abstract:
Using n-butane, n-heptane and iso-octane as representative fuels exhibiting NTC (negative temperature coefficient) behavior, comprehensive computational studies with detailed mechanisms and theoretical analysis were performed to investigate the upper stationary point, denoted as turnover states, on the NTC curve near the higher temperature regime, where the ignition delay τ exhibits a local maximum. It is found that the global behavior of the turnover states exhibits distinctive thermodynamic and kinetic characteristics under different pressures, in that the ignition delay at the turnover states shows an Arrhenius dependence on the temperature T and an approximate inverse quadratic power law dependence on the pressure P. These global behaviors imply that the temperature and pressure of the turnover states are not independent and can be correlated by Arrhenius dependence, as ln P ∝ 1/T. Further theoretical analyses demonstrate that such turnover states result from the competition between the low-temperature chain branching reactions and the decomposition of the intermediate species, and therefore correspond to a critical value, α, of the ratio of OH production from low-temperature chemistry. In addition, the ignition delay at the turnover state can be well correlated by the analytical expression derived by Peters et al., with the further demonstration that the pressure dependence of the turnover ignition delay mainly result from the H2O2 decomposition reaction. Comparison of the present results with the literature experimental data of n-heptane ignition delay time shows very good agreement.
KAUST Department:
Clean Combustion Research Center; Physical Sciences and Engineering (PSE) Division
Citation:
On the controlling mechanism of the upper turnover states in the NTC regime 2016, 164:294 Combustion and Flame
Publisher:
Elsevier BV
Journal:
Combustion and Flame
Issue Date:
18-Dec-2015
DOI:
10.1016/j.combustflame.2015.11.028
Type:
Article
ISSN:
00102180
Additional Links:
http://linkinghub.elsevier.com/retrieve/pii/S0010218015004265
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Clean Combustion Research Center

Full metadata record

DC FieldValue Language
dc.contributor.authorJi, Weiqien
dc.contributor.authorZhao, Pengen
dc.contributor.authorHe, Tanjinen
dc.contributor.authorHe, Xinen
dc.contributor.authorFarooq, Aamiren
dc.contributor.authorLaw, Chung K.en
dc.date.accessioned2016-02-10T13:02:54Zen
dc.date.available2016-02-10T13:02:54Zen
dc.date.issued2015-12-18en
dc.identifier.citationOn the controlling mechanism of the upper turnover states in the NTC regime 2016, 164:294 Combustion and Flameen
dc.identifier.issn00102180en
dc.identifier.doi10.1016/j.combustflame.2015.11.028en
dc.identifier.urihttp://hdl.handle.net/10754/596019en
dc.description.abstractUsing n-butane, n-heptane and iso-octane as representative fuels exhibiting NTC (negative temperature coefficient) behavior, comprehensive computational studies with detailed mechanisms and theoretical analysis were performed to investigate the upper stationary point, denoted as turnover states, on the NTC curve near the higher temperature regime, where the ignition delay τ exhibits a local maximum. It is found that the global behavior of the turnover states exhibits distinctive thermodynamic and kinetic characteristics under different pressures, in that the ignition delay at the turnover states shows an Arrhenius dependence on the temperature T and an approximate inverse quadratic power law dependence on the pressure P. These global behaviors imply that the temperature and pressure of the turnover states are not independent and can be correlated by Arrhenius dependence, as ln P ∝ 1/T. Further theoretical analyses demonstrate that such turnover states result from the competition between the low-temperature chain branching reactions and the decomposition of the intermediate species, and therefore correspond to a critical value, α, of the ratio of OH production from low-temperature chemistry. In addition, the ignition delay at the turnover state can be well correlated by the analytical expression derived by Peters et al., with the further demonstration that the pressure dependence of the turnover ignition delay mainly result from the H2O2 decomposition reaction. Comparison of the present results with the literature experimental data of n-heptane ignition delay time shows very good agreement.en
dc.language.isoenen
dc.publisherElsevier BVen
dc.relation.urlhttp://linkinghub.elsevier.com/retrieve/pii/S0010218015004265en
dc.rightsNOTICE: this is the author’s version of a work that was accepted for publication in Combustion and Flame. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Combustion and Flame, 18 December 2015. DOI: 10.1016/j.combustflame.2015.11.028en
dc.subjectNTCen
dc.subjectTurnoveren
dc.subjectAuto-ignitionen
dc.subjectChain branching ratioen
dc.subjectLow temperature chemistryen
dc.titleOn the controlling mechanism of the upper turnover states in the NTC regimeen
dc.typeArticleen
dc.contributor.departmentClean Combustion Research Centeren
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.identifier.journalCombustion and Flameen
dc.eprint.versionPost-printen
dc.contributor.institutionCenter for Combustion Energy, Tsinghua University, Beijing 100084, Chinaen
dc.contributor.institutionDepartment of Mechanical Engineering, Oakland University, Rochester, MI 48309, USAen
dc.contributor.institutionDepartment of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USAen
dc.contributor.institutionState Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084, Chinaen
dc.contributor.affiliationKing Abdullah University of Science and Technology (KAUST)en
kaust.authorFarooq, Aamiren
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