A well-known limitation of hydrodynamic chromatography arises from the synergistic interaction between transverse diffusion and streamwise convection, which enhances axial dispersion through the Taylor-Aris mechanism. We show that a periodic sequence of slip/no-slip conditions at the channel walls (e.g., representing wall indentations hosting stable air pockets) can significantly reduce axial dispersion, thus enhancing separation performance. The theoretical/numerical analysis is based on a generalization of Brenner’s macrotransport approach to solute transport, here modified to account for the finite-size of the suspended particles. The most effective dispersion-taming outcome is observed when the alternating sequence of slip/no-slip conditions yields non-vanishing cross-sectional flow components. The combination of these components with the hindering interaction between the chan- nel boundaries and the finite-sized particles gives rise to a non-trivial solution of Brenner’s problem on the unit periodic cell, where the cross-sectional particle number density departs from the spa- tially homogeneous condition. In turn, this effect impacts upon the solution of the so-called b-field defining the large-scale dispersion tensor, with an overall decremental effect on the axial disper- sion coefficient and on the Height Equivalent of a Theoretical Plate. Published by AIP Publishing. https://doi.org/10.1063/1.5022257

Taming axial dispersion in hydrodynamic chromatography columns through wall patterning / Adrover, Alessandra; Cerbelli, Stefano; Giona, Massimiliano. - In: PHYSICS OF FLUIDS. - ISSN 1070-6631. - 30:4(2018). [10.1063/1.5022257]

Taming axial dispersion in hydrodynamic chromatography columns through wall patterning

Adrover, Alessandra
Primo
;
Cerbelli, Stefano
Secondo
;
Giona, Massimiliano
Ultimo
2018

Abstract

A well-known limitation of hydrodynamic chromatography arises from the synergistic interaction between transverse diffusion and streamwise convection, which enhances axial dispersion through the Taylor-Aris mechanism. We show that a periodic sequence of slip/no-slip conditions at the channel walls (e.g., representing wall indentations hosting stable air pockets) can significantly reduce axial dispersion, thus enhancing separation performance. The theoretical/numerical analysis is based on a generalization of Brenner’s macrotransport approach to solute transport, here modified to account for the finite-size of the suspended particles. The most effective dispersion-taming outcome is observed when the alternating sequence of slip/no-slip conditions yields non-vanishing cross-sectional flow components. The combination of these components with the hindering interaction between the chan- nel boundaries and the finite-sized particles gives rise to a non-trivial solution of Brenner’s problem on the unit periodic cell, where the cross-sectional particle number density departs from the spa- tially homogeneous condition. In turn, this effect impacts upon the solution of the so-called b-field defining the large-scale dispersion tensor, with an overall decremental effect on the axial disper- sion coefficient and on the Height Equivalent of a Theoretical Plate. Published by AIP Publishing. https://doi.org/10.1063/1.5022257
2018
hydrodynamic chromatography; patterned microchannel; Cassie-Baxter state; slip flows; Taylor-Aris dispersion regime; Brenner-Aris dispersion theory
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Taming axial dispersion in hydrodynamic chromatography columns through wall patterning / Adrover, Alessandra; Cerbelli, Stefano; Giona, Massimiliano. - In: PHYSICS OF FLUIDS. - ISSN 1070-6631. - 30:4(2018). [10.1063/1.5022257]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1097373
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