CHEMKIN Data and NASA Polynomials
CHEMKIN® files can be used to import data for simulation of complex chemical reactions in the gas phase. These input files may contain three basic sets of information — chemical kinetics, species thermodynamic properties, and species transport properties for either volumetric or surface species. Use imported data to set up and do the following:
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Solve mass and energy balances for ideal reactor systems (reactors, semi-reactors, CSTRs, and plug flow reactors).
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Evaluate species transport properties as a function of reactor conditions.
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Evaluate mass, energy, and momentum balances for space-dependent models, and transfer them to COMSOL Multiphysics.
It is possible to read the input files for kinetics, thermodynamic, and transport properties independently and use these as separate data resources. For example, if a set of reactions is entered into the Reaction Engineering interface, species thermodynamic and transport data can be supplied by reading the appropriate input files. The full functionality of the physics interface is retained even after the import procedure. This means that all expressions and all data imported into the software are available for reference and for editing.
The following CHEMKIN files are compatible:
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Transport CHEMKIN files that supply data used to compute Transport Properties.
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Thermodynamic CHEMKIN files containing data for Gordon and McBride or NASA polynomials (Ref. 4). These polynomials are denoted NASA format and compute the species’ heat capacity, molar enthalpy, and molar entropy, in the manner of:
(2-71)
(2-72)
(2-73)
Here:
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Cp,i (SI unit: J/(mol·K)) denotes the species’ molar heat capacity,
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T (SI unit: K) is the temperature,
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Rg the ideal gas constant, 8.314 J/(mol·K),
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hi (SI unit: J/mol) is the species’ molar enthalpy, and
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si (SI unit: J/(mol·K)) represents its molar entropy at standard state.
From the CHEMKIN files the coefficients a1 to a7 are directly imported into the corresponding NASA format fields. Coefficients for NASA polynomials are available as public resources (Ref. 11).
Kinetics CHEMKIN files that can be imported in the Reversible Reaction Group feature. These consist of reaction kinetics data, such as activation energy (SI unit: J/mol).
Homogeneous Charge Compression Ignition of Methane: Application Library path Chemical_Reaction_Engineering_Module/Ideal_Tank_Reactors/compression_ignition
NOx Reduction in a Monolithic Reactor: Application Library path Chemical_Reaction_Engineering_Module/Tutorials/monolith_3d
Chemical Vapor Deposition of GaAs: Application Library path Chemical_Reaction_Engineering_Module/Reactors_with_Mass_and_Heat_Transfer/gaas_cvd