In-cylinder Combustion and Soot Evolution in the Transition from Conventional CI mode to PPC
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ArticleKAUST Department
Clean Combustion Research CenterComputational Reacting Flow Laboratory (CRFL)
Mechanical Engineering Program
Physical Science and Engineering (PSE) Division
Date
2018-01-27Online Publication Date
2018-01-27Print Publication Date
2018-02-15Permanent link to this record
http://hdl.handle.net/10754/626757
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The present study intends to explore the in-cylinder combustion and evolution of soot emission during the transition from conventional compression ignition (CI) combustion to partially premixed combustion (PPC) at low load conditions. In-cylinder combustion images and engine-out emissions were measured in an optical engine fueled with low octane heavy naphtha fuel (RON = 50). Full cycle engine simulations were performed using a three-dimensional computational fluid dynamics code CONVERGETM, coupled with gas phase chemical kinetics, turbulence, and particulate size mimic soot model. The simulations were performed under low load conditions (IMEP ~ 2 to 3 bar) at an engine speed of 1200 rpm. The start of injection (SOI) was advanced from late (-10 CAD aTDC) to early fuel injection timings (-40 CAD aTDC) to realize the combustion transition from CI combustion to PPC. The simulation results of combustion and emission are compared with the experimental results at both CI and PPC combustion modes. The results of the study show a typical low-temperature stratified lean combustion at PPC mode, while high-temperature spray-driven combustion is evident at CI mode. The in-cylinder small intermediates species such as acetylene (C2H2), propargyl (C3H3), cyclopentadienyl (C5H5) and polycyclic aromatic hydrocarbons (PAHs) were significantly suppressed at PPC mode. Nucleation reaction of PAHs collision contributed to main soot mass production. The distribution of soot mass and particle number density was consistent with the distribution of high-temperature zones at CI and PPC combustion modes.Citation
An Y, Mubarak Ali MJ, Raman V, Im HG, Johansson B (2018) In-cylinder Combustion and Soot Evolution in the Transition from Conventional CI mode to PPC. Energy & Fuels. Available: http://dx.doi.org/10.1021/acs.energyfuels.7b02535.Sponsors
This work was funded by competitive research funding from King Abdullah University of Science and Technology (KAUST), and by Saudi Aramco under the FUELCOM-II program. The authors would like to thank Adrian. I. Ichim and Riyad Jambi for their technical support in conducting the engine experiments, and Convergent Science for providing licenses for the CONVERGE software.Publisher
American Chemical Society (ACS)Journal
Energy & FuelsAdditional Links
http://pubs.acs.org/doi/10.1021/acs.energyfuels.7b02535ae974a485f413a2113503eed53cd6c53
10.1021/acs.energyfuels.7b02535