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Abstract and Applied Analysis
Volume 2013, Article ID 496243, 6 pages
Research Article

Hydrodynamic Trapping of Particles in an Expansion-Contraction Microfluidic Device

1Zhejiang University of Science and Technology, Hangzhou 310023, China
2Centre of Smart Interface, Technische Universität Darmstadt, 24878 Darmstadt, Germany

Received 8 September 2013; Accepted 8 November 2013

Academic Editor: Jianzhong Lin

Copyright © 2013 Ruijin Wang. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Manipulation and sorting of particles utilizing microfluidic phenomena have been a hot spot in recent years. Here, we present numerical investigations on particle trapping techniques by using intrinsic hydrodynamic effects in an expansion-contraction microfluidic device. One emphasis is on the underlying fluid dynamical mechanisms causing cross-streamlines migration of the particles in shear and vortical flows. The results show us that the expansion-contraction geometric structure is beneficial to particle trapping according to its size. Particle Reynolds number and aspect ratio of the channel will influence the trapping efficiency greatly because the force balance between inertial lift and vortex drag forces is the intrinsic reason. Especially, obvious inline particles contribution presented when the particle Reynolds number being unit. In addition, we selected three particle sizes (2, 7, and 15 μm) to examine the trapping efficiency.