Specify the location of the Gas-Phase Thermodynamic Database File if the default thermodynamic database file, ( thermo.db), does not contain all the gas-phase species in the CHEMKIN mechanism. The format for thermo.db is detailed in the CHEMKIN manual 39. The Chemkin thermo file format is based very closely on the NASA (1971) file format. The specifics are documented in: R.J. Rupley, and J.A.
14.2.6 Importing a Surface Kinetic Mechanism in CHEMKIN Format
Importing surface kinetic mechanisms in CHEMKIN format (Section 14.1.9) requires that the gas phase mechanism file accompany the surface mechanism file for full compatibility with CHEMKIN. If the gas phase mechanism file is not available, then you will need to create one that you will import along with the surface mechanism file. The mechanism files are imported into FLUENT using the CHEMKIN Mechanism Import panel (Figure 14.2.1).
FileImportCHEMKIN Mechanism...
In the CHEMKIN Mechanism Import panel
Note that FLUENT will initially search for the thermodynamic data in the Surface CHEMKIN Mechanism File. If the data does not exist in the mechanism file, then FLUENT will search for the thermodynamic data in the specified Thermodynamic Database File. |
To read in KINetics transport properties, go to Section 14.1.9 for detailed information.
FLUENT will create a material with the specified name, which will contain the CHEMKIN data for the species and reactions, and add it to the list of Fluent Mixture Materials. You can view all of the reactions by clicking on the Edit... button to the right of Mechanism, under Properties in the Materials panel.
Note that for surface reaction mechanisms, the surface reaction rate constant can be expressed in terms of a sticking coefficient. FLUENT will convert this sticking coefficient form to the Arrhenius rate expression [177].
![Thermo Chemkin Format Thermo Chemkin Format](http://www.afs.enea.it/project/neptunius/docs/fluent/html/ug/img4414.gif)
The CHEMKIN import facility does not provide full compatibility with all CHEMKIN rate formulations. To access more complete functionality, you should consider the KINetics module option described in Section 14.1.3. |
Compatibility and Limitations for Gas Phase Reactions
FLUENT will allow for the following reaction types:
- Arrhenius reactions with arbitrary reaction order, third-body efficiencies and non-integer stoichiometric coefficients.
- Pressure dependent reactions (Lindemann, Troe and SRI forms)
- Arbitrary reaction units
- Duplicate reactions (keyword DUP)
FLUENT will not allow for the following reaction types:
- Landau-Teller reactions (keyword LT)
- Reverse Landau-Teller reactions (keyword RLT)
- Janev reactions (keyword JAN)
- Exponential modified power series reactions(keyword FIT1)
- Radiation reactions (keyword HV)
- Energy loss reactions (keyword EXCI)
- Multi-fluid temperature dependence reactions (keyword TDEP)
- Electron momentum transfer collision frequency (keyword MOME)
- Arbitrary reverse reaction (keyword REV)
Note that the reaction types that FLUENT will not allow are mostly applicable to plasmas. |
Compatibility and Limitations for Surface Reactions
FLUENT will allow for the following reaction types:
- Arrhenius reactions with arbitrary reaction order, third-body efficiencies and non-integer stoichiometric coefficients.
- Sticking coefficients (keyword STICK). Fluent converts these to an equivalent Arrhenius expression.
- Arbitrary reaction units
- Duplicate reactions (keyword DUP)
FLUENT will not allow for the following reaction types:
- Surface Coverage modification (keyword COV)
- Ion-Energy Dependent reaction (keyword ENRGDEP)
- Bohm rate expressions (keyword BOHM)
- Ion-Enhanced reaction
- Motz-Wise correction (keywords MWON and MWOFF)
FLUENT will warn you of any incompatibilities. |
For a detailed description of the keywords, see [177].
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