Numerical and Experimental Investigation of the Depth Filtration Inside Open-cell Foam Filters
D. Hoppach1, E. Werzner2, C. Demuth2, E. Löwer1, R. Ditscherlein1, U. A. Peuker1, S. Ray2
1 Technische Universität Bergakademie Freiberg, Institute of Mechanical Process Engineering and Mineral Processing, Agricolastraße 1, 09599 Freiberg
2 Technische Universität Bergakademie Freiberg, Institute of Thermal Engineering, Chair of Gas and Heat Technology, Gustav-Zeuner-Straße 7, 09596 Freiberg,
corresponding authors E-Mail: email@example.com, firstname.lastname@example.org
The removal of non-metallic inclusions from metal melts is a crucial step in produc-ing high-quality castings that have to meet strict requirements regarding strength, toughness and machinability. In order to separate the unwanted impurities, the liq-uid metal is usually passed through ceramic foam filters, in which the inclusions adhere to the surface of a complex strut network. The development of improved filter structures requires a good understanding of the physical phenomena involved in the filtration process. In this respect, however, an experimental investigation of the real system is challenging due to the opacity of the melt, high temperatures and the common presence of a protective atmosphere. Therefore, the present study relies on water model experiments, which were carried out for different pore counts and flow velocities. In order to achieve a high degree of similarity to the real system, the wet-ting properties of the filters and particles were adjusted accordingly. Experimentally evaluated filtration efficiencies have been compared with predictions obtained from a detailed numerical model that considers the actual filter geometry, which was digit-ized using 3D X-Ray Micro Computed Tomography, and previously measured parti-cle adhesion forces. The results suggest that a considerable fraction of particles does not remain attached after collision with the filter struts. Further, the influence of pore count and flow velocity on the filtration process are discussed.