Porous Media Models Reference

After selecting the Porous Media model, you can choose to select the Porous Media Thermal Equilibrium model or Porous Media Thermal Non-Equilibrium model. To model pressure losses, you can also select the Porous Media Drag model.

Porous Media Model

Limitations

The Porous Media model supports the internal and baffle interface types for porous/porous and porous/fluid interfaces, and the contact interface type for porous/solid interfaces. If any other interface type is necessary, the Porous Media model cannot be used.

Porous Phases

You can create multiple phases under the Porous Phases manager node, to define individual porous phases. Use the Regions property of the phase to select the regions to which the porous phase applies. See Region Settings. Each phase has a Models subfolder. Right-click to select models for the phase.

The following models can be selected for individual porous phases:

• Solid
• Constant Density
• Polynomial Density
• User Defined EOS
• Segregated Solid Energy (available only with the Porous Energy Thermal Non-Equilibrium model)
• Coupled Solid Energy (available only with the Porous Energy Thermal Non-Equilibrium model)
• Electromagnetism
• Electrodynamic Potential
• Electrochemistry
• Solid Ion
• Subgrid Particle Intercalation
• Subgrid Particle Surface Film
• Surface Chemistry
• Phase Reacting Model (selected automatically when the Electrochemical Reactions model is selected in the same continuum as the Porous Media model)

Porous Phase Mass Solver Properties

Porous Media Model Region Settings

Applies to fluid regions.

Porosity

$\chi$ in Eqn. (1837), the fraction of the porous medium occupied by fluid, specified by scalar profile methods. Physically meaningful values are in the range $0<\chi \le 1$.

Initial Porosity

Available when using the Surface Chemistry model where the Surface Mechanism uses a single Bulk Species reactant or product model. $\chi$ in Eqn. (1837), the initial fraction of the porous medium occupied by fluid.

Tortuosity

$\tau$ in Species Transport in Porous Media, the ratio between actual (convoluted) path length between two points in the porous medium and the length of the straight path connecting the same points. Physically meaningful values of $\tau$ are $\ge 1$ .

Porous Phase Settings

Volume Fraction

${\alpha }_{si}$ in Eqn. (1850), the fraction of the volume of all solid porous phases occupied by this solid porous phase. If the user-specified volume fractions for all porous phases do not sum to 1 for any given region, the value of volume fraction for each porous phase is normalized such that they do sum up to 1. The normalization factor is the sum of user-specified volume fractions.

Initial Volume Fraction

Available when using the Surface Chemistry model where the Surface Mechanism uses a single Bulk Species reactant or product model. The initial ${\alpha }_{si}$ in Eqn. (1850), the fraction of the volume of all solid porous phases occupied by this solid porous phase.

Porous Media Drag Model

The Porous Media Drag model calculates pressure losses inside the porous phase.

Porous Media Drag Model Region Settings

Applies to fluid regions.

Porous Inertial Resistance

The tensor ${\mathbf{P}}_i$ as used in Eqn. (1852). All components have default value 0.

Porous Viscous Resistance

The tensor ${\mathbf{P}}_v$ as used in Eqn. (1852). All components have default value 0.

Porous Media Thermal Equilibrium and Non-Equilibrium Models

The Porous Media Thermal Equilibrium model represents the case of thermal equilibrium between the fluid and solid phases in the porous medium and solves a single energy transport equation.

The Porous Media Thermal Non-Equilibrium model represents the case of thermal non-equilibrium between the fluid and solid phases. It solves one energy transport equation for fluid temperature in the porous region and a separate energy transport equation for each solid phase.

The Porous Media Thermal Non-Equilibrium model is often more computationally expensive to run than Porous Regions or the Porous Media Thermal Equilibrium model because the combination solves extra energy transport equations.

Thermal Boundary Conditions for Porous Media Thermal Non-Equilibrium Model

Wall Boundary

Phasic Thermal Specification

Specifies thermal conditions at wall.

Condition	Corresponding Phase Condition Nodes
Phase Averaged Phase-averaged boundary condition is applied to fluid and all porous (solid) phases. This is the default.	None
Phase Specific Phase-specific boundary condition is applied to each fluid and porous phase individually.	Thermal Specification Here, you can set Condition to one of the following: Temperature Heat Flux Heat Source Adiabatic For more information, see Thermal Specification.

Contact Interface Boundary

Thermal Specification

Specifies the thermal conditions for the corresponding fluid or porous phase at the interface. This node is available under the Physics Conditions node, where it applies to the fluid phase. This node is also available under the Phase Conditions > [porous phase] node, where it applies to the porous phase. By default, fluid and all porous phases participate in heat transfer. You can set the Thermal Specification to Adiabatic to make the corresponding fluid or porous phase adiabatic at the contact interface.

Condition	Corresponding Phase Condition Nodes
Conjugate Heat Transfer The phase participates in conjugate heat transfer. This is the default.	None
Adiabatic The boundary is treated as adiabatic for the phase.	None

Internal Interface Boundary

If a porous phase spans regions on both sides of an internal interface, it conducts heat across that interface; otherwise if the porous phase is only present on one side of the interface, the interface is treated as adiabatic.

Radiation Modeling with Porous Media

All radiation models are supported for the Porous Media Thermal Equilibrium model. For the Porous Media Thermal Non-Equilibrium model, only the Surface-to-Surface (S2S) Radiation and Surface Photon Monte Carlo models are supported. In addition, for the Non-Equilibrium model, the following restrictions apply at boundaries:

• At inlets and outlets, the temperature of the phase does not affect radiation; emission is determined by the radiation temperature field as you set it.
• If you use baffle interfaces, they must be set as thermally conducting for radiation to work. Similarly, for contact interfaces, you set Thermal Specification to Conjugate Heat Transfer.
• For wall boundaries, the Phasic Thermal Specification you set to Phase Averaged to support radiation modeling.

Porous Phase-Physics Continuum Interaction Model

Use the Porous Phase-Physics Continuum Interaction model to calculate energy transfer between the solid and fluid phases of the porous region. Without this model, the energy is not exchanged between the solid and fluid phases. This model requires the use of the Porous Phase-Physics Continuum Energy Transfer model.

Porous Phase-Physics Continuum Interaction Properties

Porous Phase

Select the solid porous phase from the drop-down menu.

Fluid Phase

The phase of the fluid region specified for Porous Media model, read only.

Porous Phase-Physics Continuum Energy Transfer Model

Select this model to enable calculation of energy transfer between the phases selected with the Porous Phase-Physics Continuum Interaction model.