### 27.2.5. Multiphase

This option is used to create reactions between more than one phase. For details, see Reaction Models in the CFX-Solver Modeling Guide.

#### 27.2.5.1. Multiphase: Basic Settings

The setup of multiphase reactions is carried out by selecting the reaction Option to `Multiphase`. For details, see Multiphase Reactions and Combustion in the CFX-Solver Modeling Guide.

1. For multiphase reactions the only option available for the Material Amount Option is `Mass Coefficient`.

2. Optionally, select Reaction Description to enter a description for the reaction.

#### 27.2.5.2. Multiphase: Reactants

Multiphase reactions are specified in terms of `Parent Materials` (the phase containing a reacting material), and `Child Materials` (the reacting materials themselves).

The Parent Materials List contains the phases from which reacting materials are selected.

1. For the currently selected parent material, (such as `Coal`), select the reactant materials from that phase from the materials list (for example, Coal > Materials List).

   If a participating phase is a pure substance, it should be selected as both a parent and child material.

2. For each child material, enter a mass coefficient.

3. Reaction Order is only required for reactions of type `Mass Arrhenius`.

   If unset, it defaults to 1.

#### 27.2.5.3. Multiphase: Products

The setup on the Products tab is identical to the Reactants tab. For details, see Multiphase: Reactants.

#### 27.2.5.4. Multiphase: Multiphase Reactions

The Multiphase Reaction Rate > Option can be one of:

- Mass Arrhenius in the CFX-Solver Modeling Guide

- Gibb Char Oxidation Model in the CFX-Solver Modeling Guide

- Field Char Oxidation Model in the CFX-Solver Modeling Guide.

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