Porous Matrix
This node defines the porosity, when modeling transport in a Porous Medium or a Porous Catalyst. The porosity corresponds to the volume fraction occupied by the species containing fluid.
•
By default the porosity of the solid matrix, εp, is taken From material. The Porous Matrix node supports the use of a Porous Material added to the Materials branch. In this case the porosity is defined in the manner of
where θs,i and θimf,i are the volume fractions given in Solid and Immobile Fluids subnodes under the Porous Material node.
•
Select From pellet bed densities to compute the porosity using the (dry bulk) Bed density ρb and the (single phase) Pellet density ρpe. The porosity is then defined from
•
For User defined, enter a value or expression for the porosity.
Density
In a Porous Catalyst, the dry bulk density ρ of the porous medium is needed. This is used to compute mass phase transfer due to adsorption or desorption.
Select Dry bulk density when this quantity is known. Or select Solid phase density to instead compute the dry bulk density from the solid phase one. In both cases the density definition can be taken From material or User defined.