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ISSN Online: 2377-424X

ISBN CD: 1-56700-226-9

ISBN Online: 1-56700-225-0

International Heat Transfer Conference 13
August, 13-18, 2006, Sydney, Australia

JOULE HEATING INDUCED HEAT TRANSFER IN ELECTROKINETIC FLOW THROUGH MICROFLUIDIC CHANNELS

Get access (open in a dialog) DOI: 10.1615/IHTC13.p8.210
12 pages

摘要

Joule heating is generated inevitably when an electric field is applied across conducting media and it would impose effects on the characteristics of the electrokinetic flow in microfluidic devices. In this work, both numerical and experimental studies of the Joule heating and its effects on electroosmotic flow (EOF) in fabricated microfluidic channels are reported. The corresponding 3D mathematical models describing the Joule heating induced temperature field and its effects on the EOF in microchannels are developed. As the thermophysical and electrical properties in the models are temperature-dependent, the governing equations are strongly coupled, and thus they are solved numerically using the finite volume based CFD technique. Experiments are carried out to verify the proposed theoretical models. A Rhodamine B based thermometry technique is utilized to measure the solution temperature distributions in PDMS microfluidic channels. The micro particle image velocimetry (micro-PIV) technique is used to measure the velocity profiles of the EOF under the influence of Joule heating. The experimental results are compared with the numerical simulations, and reasonable agreement is found. Both the numerical simulations and the experimental results show that the presence of the Joule heating causes the EOF velocity to deviate from its normal “plug-like” profile; the EOF velocity exhibits a concaved shape in the hydrodynamically developing region and a convex (parabolic) pattern in the fully developed region.