TY - JOUR
T1 - Long-range electrothermal fluid motion in microfluidic systems
AU - Lu, Yi
AU - Ren, Qinlong
AU - Liu, Tingting
AU - Leung, Siu Ling
AU - Gau, Vincent
AU - Liao, Joseph C.
AU - Chan, Cho Lik
AU - Wong, Pak Kin
N1 - Funding Information:
This work was supported in part by the National Institutes of Health ( R44AI088756 and DP2OD007161 ). The authors would like to thank Jose Miguel Valdez and Minqing Li for their valuable discussion and suggestions.
Publisher Copyright:
© 2016 Elsevier Ltd
PY - 2016/7/1
Y1 - 2016/7/1
N2 - AC electrothermal flow (ACEF) is the fluid motion created as a result of Joule heating induced temperature gradients. ACEF is capable of performing major microfluidic operations, such as pumping, mixing, concentration, separation and assay enhancement, and is effective in biological samples with a wide range of electrical conductivity. Here, we report long-range fluid motion induced by ACEF, which creates centimeter-scale vortices. The long-range fluid motion displays a strong voltage dependence and is suppressed in microchannels with a characteristic length below ∼300 μm. An extended computational model of ACEF, which considers the effects of the density gradient and temperature-dependent parameters, is developed and compared experimentally by particle image velocimetry. The model captures the essence of ACEF in a wide range of channel dimensions and operating conditions. The combined experimental and computational study reveals the essential roles of buoyancy, temperature rise, and associated changes in material properties in the formation of the long-range fluid motion. Our results provide critical information for the design and modeling of ACEF based microfluidic systems toward various bioanalytical applications.
AB - AC electrothermal flow (ACEF) is the fluid motion created as a result of Joule heating induced temperature gradients. ACEF is capable of performing major microfluidic operations, such as pumping, mixing, concentration, separation and assay enhancement, and is effective in biological samples with a wide range of electrical conductivity. Here, we report long-range fluid motion induced by ACEF, which creates centimeter-scale vortices. The long-range fluid motion displays a strong voltage dependence and is suppressed in microchannels with a characteristic length below ∼300 μm. An extended computational model of ACEF, which considers the effects of the density gradient and temperature-dependent parameters, is developed and compared experimentally by particle image velocimetry. The model captures the essence of ACEF in a wide range of channel dimensions and operating conditions. The combined experimental and computational study reveals the essential roles of buoyancy, temperature rise, and associated changes in material properties in the formation of the long-range fluid motion. Our results provide critical information for the design and modeling of ACEF based microfluidic systems toward various bioanalytical applications.
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U2 - 10.1016/j.ijheatmasstransfer.2016.03.034
DO - 10.1016/j.ijheatmasstransfer.2016.03.034
M3 - Article
C2 - 27127306
AN - SCOPUS:84977666886
VL - 98
SP - 341
EP - 349
JO - International Journal of Heat and Mass Transfer
JF - International Journal of Heat and Mass Transfer
SN - 0017-9310
ER -