The geometry effect on steady electrokinetic flows in curved rectangular microchannels

Jang H. Yun, Myung S. Chun, Hyun Wook Jung

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Microfluidic designs require the effort to understand the flow pattern depending on the channel geometry. An in-depth analysis based on the theoretical model is presented for the pressure-driven electrokinetic microflows in curved rectangular channels by applying the finite volume scheme with a SIMPLE (semi-implicit method for pressure-linked equations) algorithm. The external body force originated from between the nonlinear Poisson-Boltzmann field around the channel wall and the flow-induced electric field is employed in the Navier-Stokes equation, and the Nernst-Planck equation is taken into further consideration. Unknown pressure terms of the momentum equation are solved by using the continuity equation as the pressure-velocity coupling achieves convergence. Attention is focused on the geometry effect on the fluid velocity profile at the turn of charged rectangular channels with ranging complementary channel aspect ratios (i.e., H/W=0.2-5.0). Simulation results exhibit that the streamwise axial velocity at the turn skews the profile to the inner region of the microchannel. This is due to the stronger effect of spanwise pressure gradient arising from a sufficiently low Dean number. The skewed pattern in the velocity profile becomes greater with decreasing channel aspect ratio as well as degree of the channel curvature. Quantitative predictions for the decreasing velocity due to the electrokinetic interaction were also provided in both cases of shallow and deep microchannels.

Original languageEnglish
Article number013005PHF
Pages (from-to)1-10
Number of pages10
JournalPhysics of Fluids
Volume22
Issue number5
DOIs
Publication statusPublished - 2010 May 1

Fingerprint

electrokinetics
Steady flow
microchannels
Microchannels
Geometry
geometry
Aspect ratio
aspect ratio
velocity distribution
velocity coupling
Pressure gradient
Microfluidics
wall flow
Flow patterns
Navier Stokes equations
Momentum
continuity equation
Electric fields
pressure gradients
Navier-Stokes equation

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

The geometry effect on steady electrokinetic flows in curved rectangular microchannels. / Yun, Jang H.; Chun, Myung S.; Jung, Hyun Wook.

In: Physics of Fluids, Vol. 22, No. 5, 013005PHF, 01.05.2010, p. 1-10.

Research output: Contribution to journalArticle

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