Nano Filtration Media - Challenges of Modelling and Computer Simulation

Nano filtration media become increasingly interesting for filtration applications as the production 
of nano fibers becomes cheaper. The benefit of adding nano fibers to micro fibers is the enormous
 improvement with respect to filter efficiency and the relatively low pressure drop add-on due to 
nano slip.
At the Fraunhofer ITWM, the simulation of filter media and filtration processes is traditionally performed 
resolving the smallest scale of the media. This approach has the advantage of keeping the model 
hierarchy low and the number of model parameters small. However, when entering the nano regime, 
two problems arise: The structures under consideration become huge. Hence, special algorithmic 
approaches have to be followed to overcome this hurdle. Moreover, the models for fluid flow and particle 
movement have to be extended by new physical effects like slip flow phenomena.
The paper gives an overview on the latest developments concerning nano filtration in the Fraunhofer 
software suite GeoDict / FilterDict.