Classification of ignition regimes in HCCI combustion using computational singular perturbation

Saurabh Gupta, Hong Im, Mauro Valorani

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

The Computational Singular Perturbation (CSP) technique is applied as an automated diagnostic tool to classify various ignition regimes encountered in auto-ignition processes in HCCI combustion. Various model problems representing HCCI combustion are simulated using high-fidelity computation with detailed chemistry for hydrogen-air system. The simulation data are then analyzed by CSP. In spatially homogeneous systems ignition, the occurrence of two branches of positive eigenvalues characterizes chain-branching and thermal ignition. Their merging point serves as a good indicator of the completion of the explosive stage of ignition. In spatially non homogeneous systems, this merging point can also be used to differentiate front propagation from homogeneously igniting kernels. Furthermore, to classify the front propagation as deflagration or spontaneous ignition, first the reaction zone is identified as the locus of minimum number of fast exhausted time scales (based on user-specified error thresholds). Next, the relative importance of transport and chemistry is determined in the region ahead of the reaction zone. Importance index I (Quantitative) and characteristic Damköhler number (Qualitative) are employed as criteria to discriminate the spontaneous ignition front from the deflagration front. These diagnostic tools applied to 1D laminar and 2D turbulent ignition problems allow automated detection of different ignition regimes at different times and location during the ignition events. The implication of the results in the context of modeling auto-ignition of nearly homogeneous turbulent mixtures is discussed.

Original languageEnglish (US)
Title of host publicationFall Meeting of the Eastern States Section of the Combustion Institute 2009
PublisherCombustion Institute
Pages364-373
Number of pages10
ISBN (Electronic)9781615676682
StatePublished - Jan 1 2009
EventFall Meeting of the Eastern States Section of the Combustion Institute 2009 - College Park, United States
Duration: Oct 18 2009Oct 21 2009

Publication series

NameFall Meeting of the Eastern States Section of the Combustion Institute 2009

Other

OtherFall Meeting of the Eastern States Section of the Combustion Institute 2009
CountryUnited States
CityCollege Park
Period10/18/0910/21/09

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Mechanical Engineering
  • Physical and Theoretical Chemistry

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