Ignition of a lean PRF/air mixture under RCCI/SCCI conditions: Chemical aspects

Handle URI:
http://hdl.handle.net/10754/622301
Title:
Ignition of a lean PRF/air mixture under RCCI/SCCI conditions: Chemical aspects
Authors:
Luong, Minh Bau; Yu, Gwang Hyeon; Chung, Suk-Ho ( 0000-0001-8782-312X ) ; Yoo, Chun Sang
Abstract:
Chemical aspects of the ignition of a primary reference fuel (PRF)/air mixture under reactivity controlled compression ignition (RCCI) and stratified charge compression ignition (SCCI) conditions are investigated by analyzing two-dimensional direct numerical simulation (DNS) data with chemical explosive mode (CEM) analysis. CEMA is adopted to provide fundamental insights into the ignition process by identifying controlling species and elementary reactions at different locations and times. It is found that at the first ignition delay, low-temperature chemistry (LTC) represented by the isomerization of alkylperoxy radical, chain branching reactions of keto-hydroperoxide, and H-atom abstraction of n-heptane is predominant for both RCCI and SCCI combustion. In addition, explosion index and participation index analyses together with conditional means on temperature verify that low-temperature heat release (LTHR) from local mixtures with relatively-high n-heptane concentration occurs more intensively in RCCI combustion than in SCCI combustion, which ultimately advances the overall RCCI combustion and distributes its heat release rate over time. It is also found that at the onset of the main combustion, high-temperature heat release (HTHR) occurs primarily in thin deflagrations where temperature, CO, and OH are found to be the most important species for the combustion. The conversion reaction of CO to CO and hydrogen chemistry are identified as important reactions for HTHR. The overall RCCI/SCCI combustion can be understood by mapping the variation of 2-D RCCI/SCCI combustion in temperature space onto the temporal evolution of 0-D ignition.
KAUST Department:
Clean Combustion Research Center
Citation:
Luong MB, Yu GH, Chung SH, Yoo CS (2016) Ignition of a lean PRF/air mixture under RCCI/SCCI conditions: Chemical aspects. Proceedings of the Combustion Institute. Available: http://dx.doi.org/10.1016/j.proci.2016.06.076.
Publisher:
Elsevier BV
Journal:
Proceedings of the Combustion Institute
Issue Date:
10-Oct-2016
DOI:
10.1016/j.proci.2016.06.076
Type:
Article
ISSN:
1540-7489
Appears in Collections:
Articles; Clean Combustion Research Center

Full metadata record

DC FieldValue Language
dc.contributor.authorLuong, Minh Bauen
dc.contributor.authorYu, Gwang Hyeonen
dc.contributor.authorChung, Suk-Hoen
dc.contributor.authorYoo, Chun Sangen
dc.date.accessioned2017-01-02T09:08:24Z-
dc.date.available2017-01-02T09:08:24Z-
dc.date.issued2016-10-10en
dc.identifier.citationLuong MB, Yu GH, Chung SH, Yoo CS (2016) Ignition of a lean PRF/air mixture under RCCI/SCCI conditions: Chemical aspects. Proceedings of the Combustion Institute. Available: http://dx.doi.org/10.1016/j.proci.2016.06.076.en
dc.identifier.issn1540-7489en
dc.identifier.doi10.1016/j.proci.2016.06.076en
dc.identifier.urihttp://hdl.handle.net/10754/622301-
dc.description.abstractChemical aspects of the ignition of a primary reference fuel (PRF)/air mixture under reactivity controlled compression ignition (RCCI) and stratified charge compression ignition (SCCI) conditions are investigated by analyzing two-dimensional direct numerical simulation (DNS) data with chemical explosive mode (CEM) analysis. CEMA is adopted to provide fundamental insights into the ignition process by identifying controlling species and elementary reactions at different locations and times. It is found that at the first ignition delay, low-temperature chemistry (LTC) represented by the isomerization of alkylperoxy radical, chain branching reactions of keto-hydroperoxide, and H-atom abstraction of n-heptane is predominant for both RCCI and SCCI combustion. In addition, explosion index and participation index analyses together with conditional means on temperature verify that low-temperature heat release (LTHR) from local mixtures with relatively-high n-heptane concentration occurs more intensively in RCCI combustion than in SCCI combustion, which ultimately advances the overall RCCI combustion and distributes its heat release rate over time. It is also found that at the onset of the main combustion, high-temperature heat release (HTHR) occurs primarily in thin deflagrations where temperature, CO, and OH are found to be the most important species for the combustion. The conversion reaction of CO to CO and hydrogen chemistry are identified as important reactions for HTHR. The overall RCCI/SCCI combustion can be understood by mapping the variation of 2-D RCCI/SCCI combustion in temperature space onto the temporal evolution of 0-D ignition.en
dc.publisherElsevier BVen
dc.subjectChemical explosive mode analysis (CEMA)en
dc.subjectDirect numerical simulation (DNS)en
dc.subjectPrimary reference fuel (PRF)en
dc.subjectReactivity controlled compression ignition (RCCI)en
dc.subjectStratified charge compression ignition (SCCI)en
dc.titleIgnition of a lean PRF/air mixture under RCCI/SCCI conditions: Chemical aspectsen
dc.typeArticleen
dc.contributor.departmentClean Combustion Research Centeren
dc.identifier.journalProceedings of the Combustion Instituteen
dc.contributor.institutionDepartment of Mechanical Engineering, Ulsan National Institute of Science and Technology, Ulsan 689-798, Republic of Koreaen
dc.contributor.institutionSchool of Mechanical and Nuclear Engineering, Ulsan National Institute of Science and Technology, Ulsan 689-798, Republic of Koreaen
kaust.authorChung, Suk-Hoen
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