Tutorials Manual
Tutorials Manual
Tutorials Manual
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Chemkin 4.1.1<br />
Chapter 2: Combustion in Gas-phase Processes<br />
2.8.2 Methane/Air<br />
Two somewhat different chemistry sets are used in the user tutorials to describe the<br />
combustion of methane in air or oxygen. One is the full version of GRImech 3.0, 24<br />
which includes the reactions leading to NO x formation. The other is a smaller reaction<br />
mechanism, which is used for the purposes of illustration in cases where reducing<br />
computation time is helpful.<br />
2.8.2.1 GRImech 3.0<br />
GRImech version 3.0 is a relatively well-tested reaction mechanism that was<br />
developed under the auspices of the Gas Research Institute. This reaction<br />
mechanism, consisting of gas-phase chemistry, thermodynamic, and transport data<br />
files, is provided as one of the default chemistry sets in CHEMKIN 4 in the system data<br />
folder. A detailed description of the development and extensive validation of this<br />
mechanism is available.<br />
The gas-phase kinetics input file contains 5 elements, C, H, O, N and Ar, 53 chemical<br />
species, and 325 reactions. The reaction mechanism describes the combustion of<br />
methane and smaller species such as hydrogen, as well as the formation of nitrogen<br />
oxide pollutants. Most of the reactions are reversible; only a small number of<br />
irreversible reactions are included. Many of the reactions have explicit descriptions of<br />
their pressure-dependencies, using the Troe formulation and including enhanced<br />
collision efficiencies for particular species.<br />
2.8.2.2 Reduced Mechanism<br />
This smaller reaction mechanism is from early work at Sandia National Laboratories<br />
and is given for purposes of illustration only. The gas-phase kinetics input file contains<br />
4 elements, C, H, O, and N, 17 chemical species, and 58 reversible reactions. The<br />
reaction mechanism describes the combustion of methane and smaller species such<br />
as hydrogen, but nitrogen is present as N 2 only, and does not participate in any<br />
chemical reactions. There is no explicit treatment of pressure-dependencies for<br />
reaction rates, although there are enhanced collision efficiencies for some reactions.<br />
24. http://www.me.berkeley.edu/gri-mech/.<br />
© 2007 Reaction Design 86 RD0411-C20-000-001
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