DPM on porous media
 

HI everybody, does somebody have ever modeled gas flow with particles (modeled with DPM) impacting on porous media? I got this problem: I need to simulate air flow in a channel which ends with a porous volume. Air can flow through porous volume, but particles shouldn't. Unfortunately, even particles in my simulation passes through porous media, instead they should stop on its surface, and then should escape through a secondary outlet.
So, I'm thinking that porous volume is treated by fluent just as a negative source of momentum, which slow fluid (and particles in my case), but can't stop particles. So, if it's true, I am afraid that DPM is a wrong model in my case.
Can somebody help me, or give me some information about?
Thanks