0
Research Papers: Forced Convection

Electro-Osmotic Heat Transfer of Non-Newtonian Fluid Flow in Microchannels

[+] Author and Article Information
Chien-Hsin Chen

Department of Mechanical Design Engineering, National Formosa University, Huwei, Yunlin 632, Taiwanchchen@nfu.edu.tw

J. Heat Transfer 133(7), 071705 (Apr 04, 2011) (10 pages) doi:10.1115/1.4003573 History: Received September 08, 2010; Revised January 23, 2011; Published April 04, 2011; Online April 04, 2011

A theoretical analysis is presented to explore the transport characteristics of electro-osmotic flow and associated heat transfer of non-Newtonian power-law fluids in a parallel plate microchannel. The formulation shows that the key parameters governing the current problem include the flow behavior index, the length scale ratio (ratio of Debye length to half channel height), and the Joule heating parameter (ratio of Joule heating to surface heat flux). Analytical expressions are presented for velocity and temperature profiles, the friction coefficient, and the fully developed Nusselt number. In particular, closed-form solutions are obtained for several special values of the flow behavior index. The results reveal that reducing the length scale ratio tends to increase the friction coefficient, and the friction coefficient approaches infinite for slug flow. The increase in the friction coefficient due to increasing the flow behavior index is more noticeable for a smaller length scale ratio. For surface heating, increasing the flow behavior index amplifies the temperature difference between the wall and the fluid, and thus the temperature distribution broadens; while the opposite trend is observed for surface cooling with sufficiently large Joule heating parameter with negative sign. Depending on the value of Joule heating parameter, the fully developed Nusselt number can be either increased or decreased by increasing the flow behavior index and/or the length scale ratio. The effect of flow behavior index on the Nusselt number vanishes as the length scale ratio approaches zero (the limiting case for slug flow).

FIGURES IN THIS ARTICLE
<>
Copyright © 2011 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

Comparisons of the exact solution and numerical solution for several values of n when δ=0.1: (a) dimensionless velocity profile and (b) dimensionless temperature profile with G=2

Grahic Jump Location
Figure 2

Dimensionless temperature profiles for δ=0.1 and for different values of n: (a) surface heating with G=1 and (b) surface cooling with G=−3

Grahic Jump Location
Figure 3

Dimensionless temperature profiles for G=1 and for different values of δ: (a) shear-thinning fluid with n=0.8 and (b) shear-thickening fluid with n=1.2

Grahic Jump Location
Figure 4

Dimensionless temperature profiles for δ=0.1 and for different values of G: (a) shear-thinning fluid with n=0.8 and (b) shear-thickening fluid with n=1.2

Grahic Jump Location
Figure 5

Variation of fully developed Nusselt number with δ for different values of n: (a) surface heating with G=1 and (b) surface cooling with G=−3

Grahic Jump Location
Figure 6

Variation of fully developed Nusselt number with n for different values of δ: (a) surface heating with G=1 and (b) surface cooling with G=−3

Grahic Jump Location
Figure 7

Variation of fully developed Nusselt number with δ for different values of G: (a) shear-thinning fluid with n=0.8 and (b) shear-thickening fluid with n=1.2

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In