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Proceedings Paper

Dispersion in turns for species transport by electrophoresis and electro-osmotic flow
Author(s): Stewart K. Griffiths; Robert H. Nilson
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Paper Abstract

Analytical and numerical methods are employed to investigate species transport by electrophoretic or electroosmotic motion in the curved geometry of a two-dimensional turn. Closed-form analytical solutions describing the turn-induced diffusive and dispersive spreading of a species band are presented for both the low and high Peclet number limits. We find that the spreading due to dispersion is proportional to the product of the turn included angle and the Peclet number at low Peclet numbers. It is proportional to the square of the included angle and independent of the Peclet number when the Peclet number is large. A composite solution applicable to all Peclet numbers is constructed from these limiting behaviors. Numerical solutions for species transport in a turn are also presented over a wide range of the included angle and the mean turn radius. Based on comparisons between the analytical and numerical results, we find that the analytical solutions provide very good estimates of both dispersive and diffusive spreading provided that the mean turn radius exceeds the channel width. These new solutions also agree well with data from a previous study.

Paper Details

Date Published: 18 August 2000
PDF: 12 pages
Proc. SPIE 4177, Microfluidic Devices and Systems III, (18 August 2000); doi: 10.1117/12.395665
Show Author Affiliations
Stewart K. Griffiths, Sandia National Labs. (United States)
Robert H. Nilson, Sandia National Labs. (United States)

Published in SPIE Proceedings Vol. 4177:
Microfluidic Devices and Systems III
Carlos H. Mastrangelo; Holger Becker, Editor(s)

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