Heat-transfer enhancement in AC electro-osmotic micro-flows

Heat transfer in micro-flows is essential to emerging technologies as advanced microelectronics cooling systems and chemical processes in lab-on-a-chip applications. The present study explores the potential of AC electro-osmotic (ACEO) flow forcing, a promising technique for the actuation and manipu...

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Bibliographic Details
Published in:Journal of physics. Conference series 2012-01, Vol.395 (1), p.12094-8
Main Authors: Liu, Z P, Speetjens, M F M, Frijns, A J H, Steenhoven, A A van
Format: Article
Language:English
Subjects:
Actuation
Air conditioning
Arrays
Channels
Chemical reactions
Convective heat transfer
Cooling systems
Data processing
Eigenvalues
Electric potential
Electrodes
Electronics
Heat transfer
Microchannels
New technology
Particle tracking velocimetry
Particle trajectories
Physics
Shear rate
Strain rate
Tensors
Three dimensional flow
Velocity measurement
Vorticity
Wall shear rate
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Summary:Heat transfer in micro-flows is essential to emerging technologies as advanced microelectronics cooling systems and chemical processes in lab-on-a-chip applications. The present study explores the potential of AC electro-osmotic (ACEO) flow forcing, a promising technique for the actuation and manipulation of micro-flows, for heat-transfer enhancement. Subjects of investigation include the 3D flow structure due to ACEO forcing via an array of electrodes in a micro-channel by way of 3D velocity measurements. Presence and properties of vortical structures of the 3D flow are quantified in laboratory experiments. Typical outcomes of the experimental study result from a number of 3D particle trajectories obtained by using 3D micro-Particle-Tracking Velocimetry (3D μ-PTV). The steady nature of the flow enables combination of results from a series of measurements into one dense data set. This facilitates accurate evaluation of quantities relevant for heat transfer by data-processing methods. The primary circulation is given above one half of an electrode in terms of the spanwise component of vorticity. The outline of the vortex boundary is determined via the eigenvalues of the strain-rate tensor. To estimate convective heat transfer, wall shear rate above one half of an electrode is quantitatively analyzed as function of voltage amplitude and frequency. These results yield first insights into the characteristics of 3D ACEO flows and ways to exploit and manipulate them for heat-transfer enhancement.
ISSN:1742-6588
1742-6596
DOI:10.1088/1742-6596/395/1/012094