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Hey Guys,

I try to simulate a filter process with Ansys CFX and Fluent (I try I in both Programs). The Filter Medium is a complex Geometry.

Deposition Mechanism are Inertia (I can realize it with the Particle mass), gravitation (with buoancy), diffusion and interception. And here are the problems:

Is there any way to modell diffusion? It brownsion diffusion, a random motion of very small particles. In Matlab I could realize it with sign(randn), a random number. Is in CFX or Fluent an possibilty to consider this?

The next problem is the interception. Thats the mechanism that particle hits the filterwall because of the volume of the Particle (not only a mass point). I've read that I could do it with an UDF particle termination - but for that the filter has to be a sphere/the filter must be uniform, that for example you can assign a radius. But thats not possible here. Unfortunately, the geometry is too complex. Is there another way? For example, that I generally refer it to the defined boundary condition (filter wall). I hope you know what I mean.

Many thanks for the help.