Importing Species and Reactions

Simcenter STAR-CCM+ allows you to import mechanisms in Chemkin format. You can also import species separately in Chemkin format.

To import species or mechanisms, do one of the following:
Objective Steps
Species: Importing Mixture Components from a Chemkin-formatted (.chm) File
  1. Right-click the [continuum] > Models > Multi-Component [gas] > [gas] Components node and select Import Species.
  2. In the Select file and material database dialog that appears, click Browse.
  3. In the Open dialog, navigate to and select the required file. Click Open.
  4. In the Select file and material database dialog, click OK.

    The [Gas] Components node is populated with species data.

Mechanisms: Importing Mechanisms from a Chemkin-Formatted File

When importing kinetic mechanisms in Chemkin format, it is necessary to import the Chemkin reaction mechanism file along with the corresponding NASA thermodynamic file. Importing the associated transport file is optional. See Using Thermodynamic Polynomial Data.

For laminar flame simulations, the molecular transport properties are important and therefore a transport file is generally imported. However, for turbulent flames where turbulent transport dominates over molecular transport, it is not necessary to import the molecular transport properties—constant laminar transport properties are sufficient.

  1. Right-click the Complex Chemistry or Surface-Gas Interaction node and select Import Chemistry Definition (Chemkin Format)
  2. In the Import Chemkin Files dialog that appears:
    1. Select the Fluid Chemistry Reaction File and the Fluid Thermodynamic Properties File to import.
    2. If you are simulating a laminar flame and the molecular transport properties are important:
      • Make sure that the Import Fluid Transport Properties File option is activated.
      • Select the Fluid Transport Properties File to import.
    3. If you are simulating turbulent flames, deactivate the Import Fluid Transport Properties File option.
    4. If you are importing a surface mechanism, also select the Surface Chemistry Reaction File and the Surface Thermodynamic Properties File to import—you can select more than one of each.
    5. Click OK.
    Note

    The thermodynamic properties files provide the specific heat polynomial coefficients, as well as the heat of formation, standard state entropy, and elemental composition for all species in the mechanism.

    The transport properties files provide the Lennard Jones properties: dipole, rotation, polarization, molecule type, characteristic energy, and characteristic length.

  3. Expand the [continuum] > Models node.
    • The gas components appear under the Multi-Component Gas > Gas Components node.
    • The reactions appear under the Reacting > Reactions node—or for surface chemistry mechanisms, under the Reacting Surface > Reactions node.
    • The polynomial data appears under the Material Properties > Specific Heat > Thermodynamic Polynomial Data node for each species.
    NoteIf species are imported without properties, the missing properties are copied from the standard material database—if available.

Restrictions on Importing Reactions (Within a Mechanism)

There should be no space between the stoichiometric coefficient and reactant/product.

For example, this format is invalid:

CH4 + 2 O2 => CO2 + 2 H2O

The correct format is:

CH4 + 2O2 => CO2 + 2H2O

Restrictions on Importing Species

  • Thermodynamical polynomials and molecular data also must be present for the imported species, either in the supplied files or in the user-defined files.
  • You can import either 7-coefficient or 9-coefficient thermodynamic polynomial data, however, you cannot use a mixture of these formats within the same file.
  • The species names that are used in the thermodynamic polynomial data must match the species names that are used in the chemical mechanism.
  • The species phase in the user-defined Chemkin database file must be G(gas), L(liquid), or S(solid).

Restrictions on Importing Surface Mechanisms

  • Species in the site phase must have the suffix (S).
  • Species in the bulk phase must have the suffix (B).