Kinetics modeling of shock-induced ignition in low-dilution CH{sub 4}/O{sub 2} mixtures at high pressures and intermediate temperatures
- Stanford Univ., CA (United States)
An analytical study was conducted to supplement recent high-pressure shock tube measurements of CH{sub 4}/O{sub 2} ignition at elevated pressures (40--260 atm), low dilution levels (fuel plus oxidizer {ge}30%), intermediate temperatures (1040--1500 K), and equivalence ratios as high as 6. A 38-species, 190-reaction kinetics model, based on the Gas Research Institute`s GRI-Mech 1.2 mechanism, was developed using additional reactions that are important in methane oxidation at lower temperatures. The detailed-model calculations agree well with the measured ignition delay times and reproduce the accelerated ignition trends seen in the data at higher pressures and lower temperatures. Although the expanded mechanism provides a large improvement relative to the original model over most of the conditions of this study, further improvement is still required at the highest CH{sub 4} concentrations and lowest temperatures. Sensitivity and species flux analyses were used to identify the primary reactions and kinetics pathways for the conditions studied. In general, reactions involving HO{sub 2}, CH{sub 3}O{sub 2}, and H{sub 2}O{sub 2} have increased importance at the conditions of this work relative to previous studies at lower pressures and higher temperatures. This paper represents a first step toward understanding the kinetics of CH{sub 4} ignition and oxidation at the extreme conditions of the shock tube experiments.
- OSTI ID:
- 321118
- Journal Information:
- Combustion and Flame, Journal Name: Combustion and Flame Journal Issue: 1-2 Vol. 117; ISSN CBFMAO; ISSN 0010-2180
- Country of Publication:
- United States
- Language:
- English
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