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


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
Number of pages9
Publication statusPublished - 2021
Event38th International Symposium on Combustion, 2021 - Adelaide, Australia
Duration: 2021 Jan 242021 Jan 29


Conference38th International Symposium on Combustion, 2021

Subject classification (UKÄ)

  • Mechanical Engineering

Free keywords

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


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