The secrets of filtration lie somewhere in the microcosm of filter fibers. Using computer simulation, x-ray tomography and magnetic resonance imagery researchers at MANN+HUMMEL are continually unveiling methods to produce even finer filters with even better performance and are a global leader in international research in this field.

Even as early as during my studies at Karlsruhe University (TH), I was already fascinated by particle technology in fibrous media. What happens when particles come into contact with fibers, how do they build up structures, what happens within this almost hidden world of porous structures, and how can this be discovered using simulation? The fact that I could actually verify my correct understanding of these processes blew my mind.

Virtual 3D fiber structure of a filter media

Virtual 3D fiber structure of a filter media

Tools used widely in medical science, namely x-ray tomography and magnetic resonance imagery, give us the chance to make these structures measuring thousandths of a millimeter visible. This means I can now take a virtual walk through these fibers, which I would normally not even be able to see, on a screen and visualize where particles could get caught and where the structure is better or not as good.

We have been pushing ahead with the fascinating topic of virtual filter media development here at MANN+HUMMEL for some years now. Until now, prototyping filter media has often been an art of producing porous material and not a predefined fiber structure. Fibers are added and compressed, or other parameters altered, and then tests are conducted to check whether or not filtration works.

However, in the same way that computer aided design (CAD) and computer aided engineering (CAE) are used in the car manufacturing industry we now have powerful simulation tools that open up new ways of developing innovative and superior media based on existing knowledge and hypotheses. This could involve altering the fiber design to be more open at the front, compressing the back of the structure, or adding a particular layer, for example.

For modern low-emission engines, car manufacturers need continually improved filters providing higher separation efficiency, collecting a larger amount of dust, and offering even lower pressure at a more compact size. But achieving all of these requirements is no easy feat, especially given that they contradict one another. It is for this reason that we are driving the development of advanced simulation tools for filter media, in many cases in cooperation with renowned universities and research institutes. We would like to find out more about the physics of fibrous filter media and uncover what happens within them to identify the potential for further improvements. I see huge potential in using simulation tools to generate a structure in advance and then work in partnership with our media suppliers at the production stage. As is now the established case with CAD for design, virtual development in the future will be an indispensable tool in the area of filter media development.

But even more fascinating is the challenge of linking different scales. As well as requiring a great filter medium, I also need to know how it will change when it is pleated and converted into a filter element and when all of the moving parts, such as the fibers, particles, and pleats, interact with one another. This means that simulations have to cover the full scale range from the media microstructure to the full element, which is measured in centimeters. Models have to be developed to link both scales, so that we can use a virtual medium as a basis for creating a virtual filter element that will later be sold.

In the future, we will have the opportunity to develop scenarios using simulations. We will also be able to consider extreme circumstances, such as really dusty orhumid  environments, and alter specific influencing variables that we would not be able to isolate in real life. The knowledge gained from this process will provide the foundation we need to develop innovative filtration solutions for the engines of tomorrow. That is our vision.

I think the most wonderful aspect of my work is that I have had the opportunity to play a part in shaping this field and set milestones over the past 17 years. Most people end up moving away from their specialist field when they leave university and head out into industry, but I have been lucky enough to pursue my passion for simulation together with my international team and continue to push boundaries and scale new heights.