Nonwoven filter media for aerosol filtration are subject to comprehensive analyses for characterization and optimal design referring to specific applications. Particularly for newly introduced filter media, 3D simulation of the aerosol filtration process for different fiber compositions and states of charge can accelerate the development process and improve the adjustment to specific needs.

In previous studies with the simulation software DNSlab^®, the modeling of 3D fluid flow, electric field, particle transport and deposition in nonwoven was validated by matching measured pressure drops and filtration efficiencies with simulation results. Lacking detailed experimental data on the charge distribution on the fibers surface, various possible surface charge distributions were presumed [Kerner2020].

In the present study, a new innovative nonwoven material is investigated: Lanaco EMP-160 is composed of natural wool and synthetic polymeric co-fibers, both having distinct electrical charge properties. The filter efficiencies are examined in several test series. In the first step, the filter media are discharged, and the filter efficiency is determined for uncharged fibers. In the second step, the untreated and charged filter media are examined. Electronic Force Microscopy (EFM) measurements are performed to gain insight into the surface charge of the fibers. The results of these measurements provide a charge distribution on the fiber surface, which is reproduced in the 3D simulation as shown in Fig. 1.