Species Constraint Group

For models with complex chemistries, obtaining a converged solution can be tricky, or not possible at all. The feature can be used in the following way to help in these cases:

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Add the species suspected to be causing non-convergence to the feature. Instead of solving for these species, the mass fraction will be constrained to the initial value.

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Add a study and compute the solution with the troublesome species constrained to their initial values.

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Add a second study which uses the solution from the first study as the initial value. This is done by using the options in section of the study settings. In the same study settings, the Species Constraint Group feature can be disabled using the option.

This means that the troublesome species will begin to evolve based on a physically correct, converged initial solution, rather than from a “cold start”.

In the section, add potentially troublesome species to the table. Note that the names must correspond to the exact name in the Species name field in the Species feature. For example, an argon ion should be entered into the table as Ar_1p and not Ar+.