Interphase (or heterogenous) reactions

This is only available for unsteady cases where a fractional step scheme is applied. In the first fractional step, the multiphase species Equation 14–665 is solved spatially with the reaction term set to zero. In the second fractional step, the reaction term is integrated in every cell using a stiff ODE solver. To use this option, refer to Specifying Heterogeneous Reactions in the User's Guide.

Intraphase (or homogenous) reactions

In this case, the solution algorithm is similar to that used in single-phase reacting flows described in Volumetric Reactions. ISAT can be used to accelerate detailed stiff chemistry (see In-Situ Adaptive Tabulation (ISAT) for more information). This is only available for Eulerian multiphase cases, where the stiff chemistry solver can be used for only one of the mixture phases.