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          Document History for Document ID 379683

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Document Version Version Comment Date Status
379683.0 [No comment] 14.11.2012 09:25 Released

ID: 379683.0, MPI für Dynamik komplexer technischer Systeme / Physical and Chemical Foundations of Process Engineering
Structure-transport analysis for particulate packings in trapezoidal microchip separation channels
Authors:Khirevich, S.; Höltzel, A.; Hlushkou, D.; Seidel-Morgenstern, A.; Tallarek, U.
Language:German
Date of Publication (YYYY-MM-DD):2008
Title of Journal:Lab on a Chip
Volume:8
Issue / Number:11
Start Page:1801
End Page:1808
Review Status:not specified
Audience:Experts Only
Abstract / Description:This article investigates the efficiency of particulate beds confined in quadrilateral microchannels by analyzing the three-dimensional fluid flow velocity field and accompanying hydrodynamic dispersion with quantitative numerical simulation methods. Random-close packings of uniform, solid (impermeable), spherical particles of diameter dp were generated by a modified Jodrey–Tory algorithm in eighteen different conduits with quadratic, rectangular, or trapezoidal cross-section at an average bed porosity (interparticle void fraction) of ε = 0.48. Velocity fields were calculated by the lattice Boltzmann method, and axial hydrodynamic dispersion of an inert tracer was simulated at Péclet numbers Pe = uavdp/Dm (where uav is the average fluid flow velocity through a packing and Dm the bulk molecular diffusion coefficient) from Pe = 5 to Pe = 30 by a Lagrangian particle-tracking method. All conduits had a cross-sectional area of 100dp2 and a length of 1200dp, translating to around 105 particles per packing. We present lateral porosity distribution functions and analyze fluid flow profiles and velocity distribution functions with respect to the base angle and the aspect ratio of the lateral dimensions of the different conduits. We demonstrate significant differences between the top and bottom parts of trapezoidal packings in their lateral porosity and velocity distribution functions, and show that these differences increase with decreasing base angle and increasing base-aspect ratio of a trapezoidal conduit, i.e., with increasing deviation from regular rectangular geometry. Efficiencies are investigated in terms of the axial hydrodynamic dispersion coefficients as a function of the base angle and base-aspect ratio of the conduits. The presented data support the conclusion that the efficiency of particulate beds in trapezoidal microchannels strongly depends on the lateral dimensions of the conduit and that cross-sectional designs based on large side-aspect-ratio rectangles with limited deviations from orthogonality are favorable.
© Royal Society of Chemistry 2008
[accessed October 28, 2008]
External Publication Status:published
Document Type:Article
Communicated by:Andreas Seidel-Morgenstern
Affiliations:MPI für Dynamik komplexer technischer Systeme/Physical and Chemical Foundations of Process Engineering
External Affiliations:Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Straße, 35032 Marburg, Germany
Institut für Verfahrenstechnik, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106 Magdeburg, Germany
Identifiers:URL:http://dx.doi.org/10.1039/b810688f