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Detailed numerical simulation of transient mixing and combustion of premixed methane/air mixtures in a pre-chamber/main-chamber system relevant to internal combustion engines

Qin, Fei; Shah, Ashish LU ; Huang, Zhi wei; Peng, Li-na; Tunestal, Per LU and Bai, Xue Song LU (2018) In Combustion and Flame 188. p.357-366
Abstract

Transient mixing and ignition mechanisms in a simplified pre-chamber/main-chamber system are investigated using direct numerical simulation (DNS) with detailed chemical kinetics. Full ignition and flame propagation processes in the premixed methane/air mixtures are simulated. Ignition, the progress and topology of flame evolution, and the mean burning velocity in the main chamber are analyzed in detail. Four important phases in the ignition and flame propagation processes are identified based on the flame structure development in the main chamber, the pressure and velocity evolution at typical points in both the pre-chamber and main chamber. Results show that the intermediate species OH, CH2O, and HO2 are critical... (More)

Transient mixing and ignition mechanisms in a simplified pre-chamber/main-chamber system are investigated using direct numerical simulation (DNS) with detailed chemical kinetics. Full ignition and flame propagation processes in the premixed methane/air mixtures are simulated. Ignition, the progress and topology of flame evolution, and the mean burning velocity in the main chamber are analyzed in detail. Four important phases in the ignition and flame propagation processes are identified based on the flame structure development in the main chamber, the pressure and velocity evolution at typical points in both the pre-chamber and main chamber. Results show that the intermediate species OH, CH2O, and HO2 are critical for flame stabilization and propagation in the main chamber due to their high reactivity. This is sorted as the chemical effect that the pre-chamber jet acts on the main chamber. The high temperature jet also brings heat and unburned fuel into the main chamber, which are sorted as thermal and enrichment effect, respectively. The heat release rate is found to be approximately proportional to the product of CH2O and OH mass fractions, which could be regarded as a reliable and effective marker for the heat release rate of methane/air mixtures. It is found that the mean burning velocity in the main chamber can be elevated up to 30 times under the condition investigated.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Direct numerical simulation, Flame propagation, Jet ignition, Lean natural-gas engine, Turbulent premixed combustion
in
Combustion and Flame
volume
188
pages
10 pages
publisher
Elsevier
external identifiers
  • scopus:85032290079
ISSN
0010-2180
DOI
10.1016/j.combustflame.2017.10.006
language
English
LU publication?
yes
id
b9e66bc8-cf4d-4493-ad99-d2b51f2fcb96
date added to LUP
2017-11-07 09:25:35
date last changed
2018-01-07 12:24:56
@article{b9e66bc8-cf4d-4493-ad99-d2b51f2fcb96,
  abstract     = {<p>Transient mixing and ignition mechanisms in a simplified pre-chamber/main-chamber system are investigated using direct numerical simulation (DNS) with detailed chemical kinetics. Full ignition and flame propagation processes in the premixed methane/air mixtures are simulated. Ignition, the progress and topology of flame evolution, and the mean burning velocity in the main chamber are analyzed in detail. Four important phases in the ignition and flame propagation processes are identified based on the flame structure development in the main chamber, the pressure and velocity evolution at typical points in both the pre-chamber and main chamber. Results show that the intermediate species OH, CH<sub>2</sub>O, and HO<sub>2</sub> are critical for flame stabilization and propagation in the main chamber due to their high reactivity. This is sorted as the chemical effect that the pre-chamber jet acts on the main chamber. The high temperature jet also brings heat and unburned fuel into the main chamber, which are sorted as thermal and enrichment effect, respectively. The heat release rate is found to be approximately proportional to the product of CH<sub>2</sub>O and OH mass fractions, which could be regarded as a reliable and effective marker for the heat release rate of methane/air mixtures. It is found that the mean burning velocity in the main chamber can be elevated up to 30 times under the condition investigated.</p>},
  author       = {Qin, Fei and Shah, Ashish and Huang, Zhi wei and Peng, Li-na and Tunestal, Per and Bai, Xue Song},
  issn         = {0010-2180},
  keyword      = {Direct numerical simulation,Flame propagation,Jet ignition,Lean natural-gas engine,Turbulent premixed combustion},
  language     = {eng},
  month        = {02},
  pages        = {357--366},
  publisher    = {Elsevier},
  series       = {Combustion and Flame},
  title        = {Detailed numerical simulation of transient mixing and combustion of premixed methane/air mixtures in a pre-chamber/main-chamber system relevant to internal combustion engines},
  url          = {http://dx.doi.org/10.1016/j.combustflame.2017.10.006},
  volume       = {188},
  year         = {2018},
}