| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1797929 | Journal of Magnetism and Magnetic Materials | 2016 | 9 Pages |
•Particles are focused and separated in the two branches of a U-shaped microchannel.•Negative magnetophoretic motion in ferrofluids causes the particle deflection.•A 3D numerical model is developed to simulate the particle separation.•Multiple parametric effects are studied both experimentally and numerically.•Increasing the outlet-branch width significantly enhances the particle separation.
Separating particles from a complex mixture is often necessary in many chemical and biomedical applications. This work presents a continuous-flow sheathless diamagnetic particle separation in ferrofluids through U-shaped microchannels. Due to the action of a size-dependent magnetic force, diamagnetic particles are focused into a single stream in the inlet branch of the U-turn and then continuously separated into two streams in its outlet branch. A 3D numerical model is developed to predict and understand the diamagnetic particle transport during this separation process. The numerical predictions are found to agree well with the experimental observations in a systematic study of the effects of multiple parameters including ferrofluid flow rate, concentration and magnet-channel distance. Additional numerical studies of the geometric effects of the U-turn reveal that increasing the outlet-branch width of the U-turn can significantly enhance the diamagnetic particle separation in ferrofluids.
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