Due to the pandemic Covid-19 situation the protection against infectious viruses raised the urge and importance towards the design, improvement and invention of new filter media. With increasing interest in nano fibrous filter media featuring a high filtration efficiency and low pressure drop the challenge to simulate filtration in the existence of both nano and micro fibrous layers needs to be tackled. Choosing a numerical resolution to resolve both the nano and micro fibrous layer results in large computation resources. By using the unique simulation capabilities of GeoDict software, we extract the parameters of flow resistivity and maximum packing density for both the depth and cake filtration regimes during a resolved simulation.
Knowing these and additional parameters we are able to model the nano layer as a porous layer, thus, solving the (Navier-)Stokes-Brinkman equations. In a second step, we perform an unresolved simulation with lower numerical resolution as only the micro fibrous layer needs to be resolved. The results show that the simulation when modelling the nano fibrous layer as a porous layer are in good agreement with the computation of a fully resolved simulation. Moreover, by modelling a porous layer using a lower numerical resolution, significantly lower computational costs are achieved.