Posted by Precise Simulation on
URL: http://forum.featool.com/Modeling-a-Multi-Tubular-Membrane-Reactor-tp980p1405.html

CFD2D wrote

The simulation should calculate with a membrane as a wall (only permeable for certain substances).

There is currently no pre-defined membrane boundary conditions. What you probably want is to define a Flux (Neumann) boundary condition where the magnitude of the Flux depends on a combination of concentrations etc. If you know specifically how the PDE of your membrane boundary condition looks like it would likely not be that hard to define.