Abstract
Cabin air filters are applied to prevent small particles such as pollen, fine
dust and soot amongst others from being transferred into the interior (cabin)
of a vehicle. The filter media often make use of the so called electret effect
as means for achieving high filtration efficiency at low pressure drop.
Thereby, electrostatic filtration effects are supplemented to the well-known
mechanical collection mechanisms (such as inertia, diffusion,...). Besides the
interference of several fiber-particle interactions (Coulombic
attraction/repulsion, induced dipolar forces, image charge effects)
particle-particle interactions potentially play an important role. However,
this effect is completely neglected in previous research studies due to the
high degree of complexity 1. In this work, we present a detailed
investigation of the particle behaviour in the inflow area and transition area
to the filter media. For a precise description of the underlying physical
procedures the simulation is based on a four-way coupling. This approach takes
into account the reciprocal influence between the fluid flow and the particle
motion as well as the interactions between single electrostatically charged
particles. The software package ESPResSo 2 used in this work is based on a
molecular dynamic approach and provides the advantage of efficient algorithms
for the modelling of electrostatic interactions. In order to emulate the air
flow, the molecular dynamic simulation is coupled with a Lattice-Boltzmann
fluid. The presented talk focuses on the influence of the particle-particle
interactions on the filtration performance. It is elaborated whether the fully
coupled system is necessary in order to reflect reality more closely or the
simulation can be simplified to reduce the degree of complexity and thus the
computational costs.
REFERENCES 1 S. Rief, A. Latz, A. Wiegmann, “Computer simulation of Air
Filtration including electric surface charges in three-dimensional fibrous
micro structuresâ€, Filtration 6.2, (2006). 2 A. Arnold, O. Lenz, S.
Kesselheim, R. Weeber, F. Fahrenberger, D. Roehm, P. Ko\AA¡ovan and C. Holm,
“ESPResSo 3.1: Molecular Dynamic Software for Coarse-Grained Modelsâ€,
Lecture Notes in Computational Science and Engineering, (2013).
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