The influence of porous media microstructure on filtration

We investigate how a filter media microstructure influences filtration
performance. We derive a theory that generalizes classical multiscale models
for regular structures to account for filter media with more realistic
microstructures, comprising random microstructures with polydisperse
unidirectional fibres. Our multiscale model accounts for the fluid flow and
contaminant transport at the microscale (over which the media structure is
fully resolved) and allows us to obtain macroscopic properties such as the
effective permeability, diffusivity, and fibre surface area. As the fibres grow
due to contaminant adsorption this leads to contact of neighbouring fibres. We
propose an agglomeration algorithm that describes the resulting behaviour of
the fibres upon contact, allowing us to explore the subsequent time evolution
of the filter media in a simple and robust way. We perform a comprehensive
investigation of the influence of the filter-media microstructure on filter
performance in a spectrum of possible filtration scenarios.