• Filtration processes are omnipresent in nature and quintessential to mankinds future success in surviving healthily on our planet
• To participate in preparing for this future, we try to model and simulate filtering devices and filter processes as comprehensively as possible
• To have the biggest possible impact, we make models and simulation tools known and easily usable to a community as large and interdisciplinary as possible
• Filtration also combines uniquely the need for the kinds of mathematics that we know well and enjoy doing

GeoDict implements models for creating three-dimensional realizations of nonwoven, and computing the pressure drop across the nonwoven by CFD (Computational Fluid Dynamics). FilterDict uses the computed flow field for motion and deposition of dust particles in air flow and computes the pressure drop under dust loading.

GeoDict takes into account fiber diameter distributions, Tortuosity of fibrous media, allows for layered structures, binder content, basis weight, and layer interface influence.

FilterDict is able to report MPPS, filter efficiency as a function of particle size and implements a variety of standard test particle size distributions. It takes into account particle size ranges, particle shapes via effective diameters, electrostatic charges and air flow velocity.

GeoDict and FilterDict are the only tools on the market that provide this functionality on standard hardware (16GB 64bit Windows or Linux computers). The Graphical User Interface is easy to use and can be learned with help of the 300+ page Users Guide in a few hours to days. The evaluation period of 2 months can be negotiated if necessary. The tool is in use at a variety of industrial and academic customers and in many former and ongoing projects at Fraunhofer ITWM. Filter efficiency computations requiring a single flow field computation can be achieved for realistic nonwoven models (300 x 300 x 600 computational cells) in a few hours, filter life time simulations take several days due to the need for re-computing the flow fields. The predicted filter efficiency and pressure drop evolution have been shown in previous projects and software installations to agree with measurements to within 10-20%. Trademarks and patents for GeoDict and FilterDict are in preparation.

The Software sells at around 35,000 EURO or about 50,000 USD at the current exchange rate. As mentioned, a trial period including answers to some technical questions are granted free of charge. Specific modifications to the Software can be negotiated and implemented.

Fraunhofer ITWMs department SMS has about 10 years experience with structure generation and computation of fluid flow. Since about 5 years, particle tracking and deposition are researched and the Software GeoDict and FilterDict have been on the market since Fall 2003. Key personnel are Dr. Stefan Rief, Dr. Arnulf Latz and Andreas Wiegmann, PhD (University of Washington). Each has 5-10 years experience in the field.

Micro structure simulation and virtual material design at ITWM - work that lead to FIlterDict and GeoDict.

[1] T. Geryes, Etude expérimentale et numérique de la dégradation de la mesure nucléaire d'aérosols radioactifs prélevés avec des filtres de surveillance. PhD dissertation, Institut de Radioprotection et de Surete Nucléaire, (2009).