24.2.6 Modeling Multiphase Species Transport

ANSYS FLUENT lets you describe a multiphase species transport and volumetric reaction ( this section in the separate Theory Guide) in a fashion that is similar to setting up a single-phase chemical reaction using the Species Model dialog box (e.g., Figure  24.2.3).

Models Species Edit...

Figure 24.2.3: The Species Model Dialog Box with a Multiphase Model Enabled

1.   Select Species Transport under Model.

2.   Enable Volumetric under Reactions.

3.   Select a specific phase using the Phase drop-down list under Phase Properties.

4.   Click the Set... button to display the Phase Properties dialog box (Figure  24.2.4).

Figure 24.2.4: The Phase Properties Dialog Box

In the Phase Properties dialog box, the material for each phase is listed in the Material drop-down list. From this list, you can choose the material that you want to use for a specific phase. The drop-down list contains all of the materials that have been defined for your simulation. If you want to inspect or edit any of the properties of any of the materials, then open the Edit Material dialog box by clicking the Edit... (or View...) button next to the Material drop-down list.

5.   In the Species Model dialog box, choose the Turbulence-Chemistry Interaction model. Three models are available:

Laminar Finite-Rate   computes only the Arrhenius rate (see this equation in the separate Theory Guide) and neglects turbulence-chemistry interaction.

Eddy-Dissipation   (for turbulent flows) computes only the mixing rate (see this equation and this equation in the separate Theory Guide).

Finite-Rate/Eddy-Dissipation   (for turbulent flows) computes both the Arrhenius rate and the mixing rate and uses the smaller of the two.

When modeling multiphase species transport, additional inputs may also be required depending on your modeling needs. See, for example, Section  24.2.7 for more information defining heterogeneous reactions, or Section  24.2.8 for more information on mass transfer effects.