Macroscopic filter modelling based on computational fluid and structural dynamics

U. Heck*, M. Becker, DHCAE Tools GmbH, Germany

Filter applications are important for the chemical, automotive and domestic appliances industries. DHCAE Tools developed a solver for the simulation of filters based on the open source CFD library OpenFOAM®. DHCAE Tools presents new extensions in the filter modelling, in particular Fluid-structure interactions (FSI) with the open-source structural solver CalculiX and the treatment of resistance regions.

The numeric models describe the interactions of discrete particles in a continuous flow with thin-walled, porous media on a macroscopic scale. Due to the complex geometries of bag filter houses, the filter elements are defined as 2D porous baffles (Figure 1).

Figure 1 - Clogged filter bag and streamlines.

An iterative algorithm was implemented to simulate the filter loading. Starting with a steady state flow field, a certain mass is injected as Lagrangian particles and tracked with a local time stepping (LTS) approach. The increasing particle concentration is stored on each single face of the filter baffle mesh. With the local particle concentration, the non-uniform resistance of the filter is recalculated. While the particles are collected on the 2d face representation, the according resistance is either assigned to the 2d face elements directly or to a layer of several volume cells in front and behind the filter face. In new additional volume implementations the resistance values are automatically estimated considering the particle mass, collected on the filter and local cell sizes. Furthermore a volume representation allows higher base resistances caused by the clean filter resulting in...

Session: F5 - Filter Media - Numerical Methods for Optimized Media Design II
Day: 14 March 2018
Time: 16:45 - 18:00 h

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