title: A Planar Microfluidic Mixer Based on Logarithmic Spirals.
abstract: A passive, planar micromixer design based on logarithmic spirals is presented. The device was fabricated using polydimethylsiloxane soft photolithography techniques, and mixing performance was characterized via numerical simulation and fluorescent microscopy. Mixing efficiency initially declined as Reynolds number increased, and this trend continued until a Reynolds number of 15 where a minimum was reached at 53%. Mixing efficiency then began to increase reaching a maximum mixing efficiency of 86% at Re = 67. Three-dimensional simulations of fluid mixing in this design were compared to other planar geometries such as the Archimedes spiral and Meandering-S mixers. The implementation of logarithmic curvature offers several unique advantages that enhance mixing, namely a variable cross-sectional area and a logarithmically varying radius of curvature that creates 3-D Dean vortices. These flow phenomena were observed in simulations with multilayered fluid folding and validated with confocal microscopy. This design provides improved mixing performance over a broader range of Reynolds numbers than other reported planar mixers, all while avoiding external force fields, more complicated fabrication processes, and the introduction of flow obstructions or cavities that may unintentionally affect sensitive or particulate-containing samples. Due to the planar design requiring only single-step lithographic features, this compact geometry could be easily implemented into existing micro-total analysis systems requiring effective rapid mixing.
authors: Cain Department of Chemical Engineering Louisiana State University 110 South Stadium Drive Baton Rouge, LA 70803, USA.
authors: Thomas
authors: T
authors: Scherr
authors: Christian
authors: C
authors: Quitadamo
authors: Preston
authors: P
authors: Tesvich
authors: Daniel Sang-Won
authors: DS
authors: Park
authors: Terrence
authors: T
authors: Tiersch
authors: Daniel
authors: D
authors: Hayes
authors: Jin-Woo
authors: JW
authors: Choi
authors: Krishnaswamy
authors: K
authors: Nandakumar
authors: W Todd
authors: WT
authors: Monroe
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