Numerical simulation of a mixed-mode reaction front in a PPC engine

Christian Ibron, Hesammedin Fatehi, Zhenkan Wang, Panagiota Stamatoglou, Marcus Lundgren, Marcus Aldén, Mattias Richter, Öivind Andersson, Xue Song Bai

Research output: Chapter in Book/Report/Conference proceedingPaper in conference proceedingpeer-review

Abstract

The ignition process, mode of combustion and reaction front propagation in a partially premixed combustion (PPC) engine running with a primary reference fuel (87 vol% iso-octane, 13 vol% n-heptane) were investigated numerically in a large eddy simulation (LES). A one-equation sub-grid scale model coupled to the partially stirred reactor model and a finite rate chemical model were used in LES. Different combustion modes, ignition front propagation, premixed flame and non-premixed flame, were observed simultaneously. Displacement speed of CO iso-surface propagation described the transition of premixed auto-ignition to non-premixed flame. High temporal resolution optical data of CH2O and chemiluminescence were compared with simulated results. A high-speed ignition front was found to expand through fuel-rich mixture and stabilize around stoichiometry in a non-premixed flame while lean premixed combustion occurs in the spray wake at a much slower pace. A good qualitative agreement of the distribution of chemiluminescence and CH2O formation and destruction indicated that the simulation approach sufficiently captures the driving physics of mixed-mode combustion in PPC engines. The transition from auto-ignition to flame occurs over a period of several crank angles and the reaction front propagation can be captured using the described model.

Original languageEnglish
Title of host publicationProceedings of the Combustion Institute
PublisherElsevier
Pages5703-5711
Number of pages9
Volume38
Edition4
DOIs
Publication statusPublished - 2021
Event38th International Symposium on Combustion, 2021 - Adelaide, Australia
Duration: 2021 Jan 242021 Jan 29

Conference

Conference38th International Symposium on Combustion, 2021
Country/TerritoryAustralia
CityAdelaide
Period2021/01/242021/01/29

Subject classification (UKÄ)

  • Mechanical Engineering

Free keywords

  • Ignition
  • Low temperature combustion
  • Mixed-mode combustion
  • Partially premixed combustion
  • Reaction front

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