This interface (
), found under the Chemical Species Transport branch (
), is used to calculate the chemical composition in a fluid mixture transported through the interstices of a porous media. The interface is the same as the
Transport of Concentrated Species interface but it has a
Porous Medium node added by default. All other features for porous media transport is always available.
The main feature of the interface is the Porous Medium node which adds the governing equations for the mass fractions of all present species. It has two subnodes,
Fluid and
Porous Matrix, which in turn are used to define the physical properties corresponding to each phase, and to prescribe the transport properties. The latter are typically the flow field, and when applicable, the electric field. The
Porous Medium node supports the use of a
Porous Material (described in the
COMSOL Multiphysics Reference Manual) for defining phase-specific properties, and for sharing them among different physics interfaces.
When this physics interface is added, the following default nodes are also added to the Model Builder —
Porous Medium,
No Flux (the default boundary condition), and
Initial Values. Then, from the
Physics toolbar, add other nodes that implement, for example, boundary conditions, reaction rate expressions, and species sources. You can also right-click
Transport of Concentrated Species in Porous Media to select physics features from the context menu.