Investigation of Chemical Kinetics on Soot Formation Event of n-Heptane Spray Combustion

Kar Mun Pang, Mehdi Jangi, Xue-Song Bai, Jesper Schramm

    Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review


    In this reported work, 2-dimsensional computational fluid dynamics studies of n-heptane combustion and soot formation processes in the Sandia constant-volume vessel are carried out. The key interest here is to elucidate how the chemical kinetics affects the combustion and soot formation events. Numerical computation is performed using OpenFOAM and chemistry coordinate mapping (CCM) approach is used to expedite the calculation. Three n-heptane kinetic mechanisms with different chemistry sizes and comprehensiveness in oxidation pathways and soot precursor formation are adopted. The three examined chemical models use acetylene (C2H2), benzene ring (A1) and pyrene (A4) as soot precursor. They are henceforth addressed as nhepC2H2, nhepA1 and nhepA4, respectively for brevity. Here, a multistep soot model is coupled with the spray combustion solver to simulate the soot formation/oxidation processes. Comparison of the results shows that the simulated ignition delay times and liftoff lengths have good agreements with the experimental measurements across wide range of operating conditions when the nhepC2H2 model is implemented. The performance of this mechanism however drops in cases with low ambient temperatures. Besides, the overall soot precursor and particle distribution prediction is found to be improved with the use of A4 as soot precursor. The variation of the soot precursor production with respect to the change of ambient temperature and oxygen levels qualitatively agrees with that of the conceptual models. Also, the revised nhepC2H2 model replicates the experimental spatial soot distribution reasonably well, although the absolute soot volume fraction values are not reproduced with the default soot model constant values.
    Original languageEnglish
    Title of host publicationTechnical Papers - SAE 2014 World Congress & Exhibition
    Number of pages16
    PublisherSociety of Automotive Engineers
    Publication date2014
    Publication statusPublished - 2014
    EventSAE 2014 World Congress & Exhibition - Detroit, MI, United States
    Duration: 8 Apr 201410 Apr 2014


    ConferenceSAE 2014 World Congress & Exhibition
    Country/TerritoryUnited States
    CityDetroit, MI
    Internet address
    SeriesS A E Technical Papers


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