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3D physically reconstructed silica monoliths

Figure: Ulrich Tallarek

The lattice-Boltzmann method (LBM) allows detailed 3D modeling of the pore-scale fluid flow field in porous media with complex solid–liquid interface geometry. The large computational work-flow that arises from using a finely resolved realistic structure of macroscopically representative samples of porous media is managed by implementation of the LBM-model at parallel high-performance computational systems (supercomputers).

Panel A shows a domain (61 µm x 61 µm x 23 µm) from the bulk region of a silica monolith as reconstructed by confocal laser scanning microscopy (spatial resolution, 30 nm). The same resolution was also used for the LBM-simulation in order to calculate the 3D flow velocity field in the reconstructed domain.

Panels B and C show an individual two-dimensional slice from the reconstructed monolith and the distribution of the calculated longitudinal flow velocity component.

Panel D compares the simulated superficial flow velocity (lines) as a function of the applied pressure gradient and experimental data (symbols) for two generations of analytical silica monoliths with different pore-space morphology used for liquid chromatography and heterogeneously supported continuous-flow synthesis.

Panel E shows transient longitudinal dispersion coefficients DL(t) normalized by Dm vs. the transverse dispersion length (2DTt)1/2 in the reconstructed bulk macropore space of 1st and 2nd generation analytical silica monoliths at uav = 6.0 and 6.25 mm/s, respectively. Dashed lines indicate asymptotic values (DL) and the corresponding characteristic lengths.