Microfluidics and Nanofluidics

, 5:809

Simulations of extensional flow in microrheometric devices

  • Mónica S. N. Oliveira
  • Lucy E. Rodd
  • Gareth H. McKinley
  • Manuel A. Alves
Research Paper

DOI: 10.1007/s10404-008-0277-5

Cite this article as:
Oliveira, M.S.N., Rodd, L.E., McKinley, G.H. et al. Microfluid Nanofluid (2008) 5: 809. doi:10.1007/s10404-008-0277-5

Abstract

We present a detailed numerical study of the flow of a Newtonian fluid through microrheometric devices featuring a sudden contraction–expansion. This flow configuration is typically used to generate extensional deformations and high strain rates. The excess pressure drop resulting from the converging and diverging flow is an important dynamic measure to quantify if the device is intended to be used as a microfluidic extensional rheometer. To explore this idea, we examine the effect of the contraction length, aspect ratio and Reynolds number on the flow kinematics and resulting pressure field. Analysis of the computed velocity and pressure fields show that, for typical experimental conditions used in microfluidic devices, the steady flow is highly three-dimensional with open spiraling vortical structures in the stagnant corner regions. The numerical simulations of the local kinematics and global pressure drop are in good agreement with experimental results. The device aspect ratio is shown to have a strong impact on the flow and consequently on the excess pressure drop, which is quantified in terms of the dimensionless Couette and Bagley correction factors. We suggest an approach for calculating the Bagley correction which may be especially appropriate for planar microchannels.

Keywords

MicrofluidicsMicrorheometryCouette correctionBagley correctionContraction–expansion flowExtensional flow

Supplementary material

10404_2008_277_MOESM1_ESM.pdf (418 kb)
Supplementary material (PDF 417 kb)

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • Mónica S. N. Oliveira
    • 1
  • Lucy E. Rodd
    • 2
    • 3
  • Gareth H. McKinley
    • 2
  • Manuel A. Alves
    • 1
  1. 1.CEFT, Departamento de Engenharia QuímicaFaculdade de Engenharia da Universidade do PortoPortoPortugal
  2. 2.Department of Mechanical EngineeringMITCambridgeUSA
  3. 3.Department of Chemical and Biomolecular EngineeringThe University of MelbourneMelbourneAustralia