Microfluidic converging/diverging channels optimised for homogeneous extensional deformation

K. Zografos, F. Pimenta, M. A. Alves, M. S. N. Oliveira

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31 Citations (Scopus)
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In this work we optimise microfluidic converging/diverging geometries in order to produce constant strain-rates along the centreline of the flow, for performing studies under homogeneous extension. The design is examined for both two-dimensional and three-dimensional flows where the effects of aspect ratio and dimensionless contraction length are investigated. Initially, pressure driven flows of Newtonian fluids under creeping flow conditions are considered, which is a reasonable approximation in microfluidics, and the limits of the applicability of the design in terms of Reynolds numbers are investigated. The optimised geometry is then used for studying the flow of viscoelastic fluids and the practical limitations in terms of Weissenberg number are reported. Furthermore, the optimisation strategy is also applied for electro-osmotic driven flows, where the development of a plug-like velocity profile allows for a wider region of homogeneous extensional deformation in the flow field.
Original languageEnglish
Article number043508
Number of pages21
Issue number4
Early online date5 Jul 2016
Publication statusPublished - 31 Jul 2016


  • extensional flow
  • electro-osmotic flow
  • viscoelastic fluids
  • diverging channels
  • converging channels
  • optimisation


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