### 27.1.2. Material Details View: Common Settings

#### 27.1.2.1. Option

Any material can consist of one or more materials. If a material contains only a single pure species, then it is known as a pure substance. If it contains more than one species, then it is known as a mixture. The materials are assumed to be mixed at the molecular level in the mixture.

The type of material is set using the following options:

- The `Pure Substance` option should be used to create a fluid whose properties, such as viscosity, density, or molar mass, are known. All existing and newly created pure substances appear in the materials list and you can then create mixtures from them. For details, see Material Details View: Pure Substance.

- The `Fixed Composition Mixture` option should be used to create a mixture with fixed mass fractions of each material. The mass fraction of each material is specified and is not allowed to change during the course of the simulation in space or time. For details, see Material Details View: Fixed Composition Mixture.

- The `Variable Composition Mixture` option should be used to create a mixture whose mass fractions are allowed to change during the course of a simulation in space and time. The mass fraction of each material is not specified when defining the fluid. You can use a fixed composition mixture as a material in a variable composition mixture.

  For details, see Material Details View: Variable Composition Mixture.

- The `Homogeneous Binary Mixture` option applies to equilibrium phase change calculations. For details, see Material Details View: Homogeneous Binary Mixture.

- The `Reacting Mixture` option is used for a chemical reaction, such as combustion.

  For details, see Material Details View: Reacting Mixture.

- The `Hydrocarbon Fuel` option. For details, see Material Details View: Hydrocarbon Fuel.

#### 27.1.2.2. Material Group

The Material Group filter is used to group materials by type, as well as restrict what materials can be mixed when the physical models include reactions or phase change. A material can be a member of more than one material group if it has a consistent set of properties. Material Group will always be set to at least one of the following:

##### 27.1.2.2.1. User

Any user-defined materials, not assigned to one of the other groups, are shown in or can be added to this group. For example, materials loaded from a previous CFX-Pre simulation are shown in this group.

##### 27.1.2.2.2. Air Data

This group contains Ideal Gas and constant property air. Constant properties are for dry air at both 0 [C], 1 [atm] (STP) and 25 [C], 1 [atm].

##### 27.1.2.2.3. CHT Solids

Contains solid substances that can be used for solid domains when performing conjugate heat transfer modeling.

##### 27.1.2.2.4. Calorically Perfect Ideal Gases

Contains gases that obey the Ideal Gas Law.

##### 27.1.2.2.5. Constant Property Gases / Liquids

These groups contain gas and liquid substances with constant properties.

The gas properties are calculated at STP (0 [C] and 1 [atm]). Gas materials in this group can be combined with NASA SP-273 materials for use in combustion modeling simulations.

##### 27.1.2.2.6. Dry/Wet Redlich Kwong

No materials appear in this group by default, they must be loaded from a pre-supplied materials file. All materials in this group use the built-in Redlich-Kwong equation of state and are suitable for performing equilibrium, homogeneous, phase change modeling.

For any given pure substance, there are three different materials. There is a material with a `RK` tag, used for dry vapor calculations, and three materials with `RKv`, `RKl` and `RKlv` suffixes, which are used for equilibrium phase change (wet vapor) calculations.

##### 27.1.2.2.7. Dry/Wet Redlich Kwong RGP

No materials appear in this group by default, they must also be loaded from a pre-supplied materials file. All materials in this group use the Redlich-Kwong equation of state with properties specified in a TASCflow RGP file. These materials are suitable for performing equilibrium, homogeneous, phase change modeling.

Like the built-in Redlich Kwong group, for any given pure substance there are three different materials. There is a material with a `RK` tag, used for dry vapor calculations, and three materials with `RKv`, `RKl` and `RKlv` suffixes, which are used for equilibrium phase change (wet vapor) calculations.

##### 27.1.2.2.8. Dry/Wet Peng Robinson RGP

No materials appear in this group by default, they must also be loaded from a pre-supplied materials file. All materials in this group use the Redlich-Kwong equation of state with properties specified in a TASCflow RGP file. These materials are suitable for performing equilibrium, homogeneous, phase change modeling.

Like the built-in Redlich Kwong group, for any given pure substance there are three different materials. There is a material with a `RK` tag, used for dry vapor calculations, and three materials with `RKv`, `RKl` and `RKlv` suffixes, which are used for equilibrium phase change (wet vapor) calculations.

##### 27.1.2.2.9. Dry/Wet Soave Redlich Kwong RGP

No materials appear in this group by default, they must also be loaded from a pre-supplied materials file. All materials in this group use the Redlich-Kwong equation of state with properties specified in a TASCflow RGP file. These materials are suitable for performing equilibrium, homogeneous, phase change modeling.

Like the built-in Redlich Kwong group, for any given pure substance there are three different materials. There is a material with a `RK` tag, used for dry vapor calculations, and three materials with `RKv`, `RKl` and `RKlv` suffixes, which are used for equilibrium phase change (wet vapor) calculations.

##### 27.1.2.2.10. Dry/Wet Steam

No materials appear in this group by default, they must also be loaded from a pre-supplied materials file. Materials in this group use the IAPWS equation of state. Again, the materials are suitable for either dry or wet steam calculations.

##### 27.1.2.2.11. Gas Phase Combustion

Contains materials that can be used for gas phase combustion. All materials in this group use the Ideal Gas equation of state. The specific heat capacity, enthalpy and entropy for each of the materials are specified using the NASA SP-273 format. For details, see NASA Format in the CFX-Solver Modeling Guide.

##### 27.1.2.2.12. Interphase Mass Transfer

This group contains materials that can be used for Eulerian or Lagrangian interphase mass transfer. This group currently contains a number of materials that have liquid or gas reference states, which are consistent for performing phase change calculations. The gas phases use the ideal gas equation of state and temperature-dependent specific heat capacity. The associated liquid phases use constant properties.

##### 27.1.2.2.13. Particle Solids

Contains a list of solids that can be used in Particle Tracking calculations.

##### 27.1.2.2.14. Soot

This group contains solid substances that can be used when performing soot calculations.

##### 27.1.2.2.15. Water Data

This group contains liquid and vapor water materials with constant properties. The materials in this group can be combined with NASA SP-273 materials for use in combustion modeling simulations.

#### 27.1.2.3. Material Description

This parameter can be toggled on to view a detailed description of the substance. Click Edit the Material Description to edit the description (to a maximum of 120 alphanumeric characters).

#### 27.1.2.4. Thermodynamic State

This parameter sets the state of a substance to solid, liquid or gas. There are certain limitations imposed by selecting a particular state. For example, a solid must always have at least density, specific heat capacity and thermal conductivity specified.

#### 27.1.2.5. Coordinate Frame

For material properties that are set using expressions containing X, Y, or Z, you may want to supply a custom coordinate frame as the basis for evaluation of such properties. For details, see Coordinate Frame, Coordinate Frames, and Coordinate Frames in the CFX-Solver Modeling Guide.

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