Efficient heat transfer enhancement by elastic turbulence with polymer solution in a curved microchannel

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• 作者：Dong-Yang Li ; Xiao-Bin Li ; Hong-Na Zhang ; Feng-Chen Li…
• 关键词：Elastic turbulence ; Microfluidic ; Microheat transfer ; Heat transfer enhancement ; Viscoelastic fluid
• 刊名：Microfluidics and Nanofluidics
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：21
• 期：1
• 全文大小：
• 刊物类别：Engineering
• 刊物主题：Engineering Fluid Dynamics; Biomedical Engineering; Analytical Chemistry; Nanotechnology and Microengineering;
• 出版者：Springer Berlin Heidelberg
• ISSN：1613-4990
• 卷排序：21

文摘

Heat and mass transfer in microscale flows are limited due to extremely low Reynolds number (Re). In a curved microchannel, however, complex flow behaviors, such as elastic instability and elastic turbulence, can be induced via viscoelastic fluid at vanishingly low-Re conditions, which is of great potential to enhance the heat transfer performance. The influence of elastic instabilities and turbulence on heat dissipation of exothermic components is experimentally investigated in this study. The heat transfer performance of both viscoelastic (polymer solutions) and Newtonian (sucrose solutions) fluid flows in a curved microchannel with a square cross section is experimentally characterized. Titanium–platinum (Ti–Pt) thin films embedded at the bottom wall of the polydimethylsiloxane (PDMS) microchannel serve as both microheater and temperature sensor. For viscoelastic fluids, the spectrum of outlet temperature fluctuation in broad frequency (f) region fits the power law of f−1.1. Heat transfer enhancement due to the elastic turbulence in a curved microchannel is thereby identified by the drastic growth of the Nusselt number (Nu, the ratio of convective to conductive heat transfer normal to the boundary) with the increase in the Weissenberg number (Wi, the ratio of elastic stress to viscous stress). The mechanism of heat transfer enhanced by the convection effect of elastic turbulence is also elucidated.