This node defines the porosity and material properties of the pellets contained in a packed bed, used in the heat transfer equations of the Porous Medium parent node, when the
Packed bed option is selected in the
Porous medium type list. The coupling condition between the pellets and the fluid phase of the packed bed can be specified in the
Pellet-Fluid Interface (Porous Medium) subnode.
This section is available when a temperature-dependent density defined in a material is used. On the material frame, the density is evaluated in relation to a reference temperature in order to ensure conservation of the mass in the presence of temperature variations. By default the Common model input is used. This corresponds to the variable
minput.Tempref, which is set to 293.15 K by default. To edit it, click the
Go to Source button (
), and in the
Default Model Inputs node under
Global Definitions, set a value for the
Volume reference temperature in the
Expression for remaining selection section.
Other options are User defined and all the temperature variables from the physics interfaces included in the model.
This section is available when material properties are temperature-dependent. By default, the temperature of the parent interface is used and the section is not editable. To edit the Temperature field, click
Make All Model Inputs Editable (
). The available options are
User defined (default),
Common model input (the
minput.T variable, set to 293.15 K by default) and all temperature variables from the physics interfaces included in the model. To edit the
minput.T variable, click the
Go to Source button (
), and in the
Default Model Inputs node under
Global Definitions, set a value for the
Temperature in the
Expression for remaining selection section.
The default Bed porosity εp of the packed bed is taken
From material. In a
Porous Material node, the porosity is defined as follows:
where θsi,
θpe, and
θimfi are the volume fractions of the
Solid,
Pellet, and
Immobile Fluid subnodes under the
Porous Material node.
For User defined, enter a value or expression.
As porosity can be considered within the pellets, set the Pellet porosity,
εpe. By default it is taken
From material. Go to the
Pellet subnode of the
Porous Material node to enter a value or expression.
Set the thermal conductivity of the porous matrix within the pellets, kpe. It is used to compute the effective thermal conductivity of the pellet filled with fluid,
kpe,eff, defined by
The default Thermal conductivity kpe is taken
From material. For
User defined, enter a value or expression. A scalar value should be set as it is used in the 1D microscale equation.
The Density ρpe and the
Specific heat capacity Cp, pe should be specified. For
From Material option, see
Material Density in Features Defined in the Material Frame if a temperature-dependent density should be set.
Physics tab with Porous Medium selected in the model tree: