Influence of an inhomogeneous material distribution on the overall filtration efficiency of fibrous media

It is well known that the level of uniformity of nonwoven filter materials is related to their filtration efficiency and therefore, this feature is an important subject to quality control (QC). The COVID19 pandemic has once again revealed the importance of efficient manufacturing processes for high-quality nonwovens, such as they are required for face masks that provide sufficient protection. While specialized 3D computer simulations have shown to be very helpful for the design and optimization of nonwovens, their computational cost is (in general) too high to allow for a quick assessment of the properties of a filter material. In addition, the acquisition of images of the microstructure created during production is not practicable.