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dc.contributor.authorZhang, Jiabo
dc.contributor.authorLuong, Minh Bau
dc.contributor.authorPérez, Francisco E.Hernández
dc.contributor.authorHan, Dong
dc.contributor.authorIm, Hong G.
dc.contributor.authorHuang, Zhen
dc.date.accessioned2021-01-11T11:11:13Z
dc.date.available2021-01-11T11:11:13Z
dc.date.issued2020-12-29
dc.date.submitted2020-07-20
dc.identifier.citationZhang, J., Luong, M. B., Pérez, F. E. H., Han, D., Im, H. G., & Huang, Z. (2021). Exergy loss characteristics of DME/air and ethanol/air mixtures with temperature and concentration fluctuations under HCCI/SCCI conditions: A DNS study. Combustion and Flame, 226, 334–346. doi:10.1016/j.combustflame.2020.12.028
dc.identifier.issn1556-2921
dc.identifier.issn0010-2180
dc.identifier.doi10.1016/j.combustflame.2020.12.028
dc.identifier.urihttp://hdl.handle.net/10754/666865
dc.description.abstractThe exergy loss characteristics of combustion processes under homogeneous-charge compression ignition (HCCI) and stratified-charge compression ignition (SCCI) conditions are numerically investigated by analyzing two-dimensional (2-D) direct numerical simulation (DNS) data. Two fuels, dimethyl ether and ethanol, together with the initial conditions of different mean temperatures, and levels of temperature and concentration fluctuations relevant to HCCI/SCCI conditions were investigated. It is found that the prevalent deflagration mode significantly decreases the maximum exergy loss rates and spreads out the exergy loss rate for all the cases regardless of fuel types, temperature regimes, and temperature and/or concentration fluctuations. The primary irreversible sources of exergy loss are also identified. The chemical reaction is found to be the primary contributor to the total exergy loss, followed by heat conduction and mass diffusion, regardless of the fluctuation levels. It is also found that the relative change of exergy loss due to chemical reactions, ELchemrel, correlates strongly with the heat release fraction by deflagration. The maximum ELchemrel is found to be less than 10%. Chemical pathway analysis reveals that the exergy loss induced by low-temperature reactions, represented by the decomposition of hydroperoxy–alkylperoxy and the H-abstraction reactions of the fuel molecule, is much lower under the SCCI conditions than that under the HCCI conditions. Generally, the dominant reactions contributing to the exergy loss in the high-temperature regime are nearly identical for the HCCI and SCCI combustion. Key reactions, including the H2O2 loop reactions, the reactions of the H2–O2 mechanism, and the conversion reaction of CO to CO2, CO+OH=CO2+H, are found to contribute more than 50% of the total exergy loss. Due to locally higher reactivities by temperature and concentration fluctuations inducing deflagration dominance, these reactions occur at a relatively higher temperature (1600 K–1900 K) compared with the homogeneous zero-dimensional cases (∼1400 K), resulting in a net reduction in exergy loss.
dc.description.sponsorshipThe authors would like to thank Prof. Tianfeng Lu for providing the code to leverage between the reduced mechanism and the skeletal mechanism. This work was sponsored by the research funding from King Abdullah University of Science and Technology, and National Natural Science Foundation of China (Grant Nos. 51861135303 and 51776124). This research used the computational resources of the KAUST Supercomputing Laboratory (KSL).
dc.publisherElsevier BV
dc.relation.urlhttps://linkinghub.elsevier.com/retrieve/pii/S0010218020305770
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, [226, , (2020-12-29)] DOI: 10.1016/j.combustflame.2020.12.028 . © 2020. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
dc.titleExergy loss characteristics of DME/air and ethanol/air mixtures with temperature and concentration fluctuations under HCCI/SCCI conditions: A DNS study
dc.typeArticle
dc.contributor.departmentClean Combustion Research Center
dc.contributor.departmentComputational Reacting Flow Laboratory (CRFL)
dc.contributor.departmentMechanical Engineering Program
dc.contributor.departmentPhysical Science and Engineering (PSE) Division
dc.identifier.journalCombustion and Flame
dc.rights.embargodate2022-12-29
dc.eprint.versionPost-print
dc.contributor.institutionKey Laboratory for Power Machinery and Engineering, Ministry of Education, Shanghai Jiao Tong University, Shanghai 200240, China
dc.identifier.volume226
dc.identifier.pages334-346
kaust.personLuong, Minh Bau
kaust.personPérez, Francisco E.Hernández
kaust.personIm, Hong G.
dc.date.accepted2020-12-16
dc.identifier.eid2-s2.0-85098732121
refterms.dateFOA2021-01-11T12:09:12Z
kaust.acknowledged.supportUnitKAUST Supercomputing Laboratory (KSL)


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