0
Research Papers: Micro/Nanoscale Heat Transfer

Thermal Transport in a Microchannel Exhibiting Ultrahydrophobic Microribs Maintained at Constant Temperature

[+] Author and Article Information
D. Maynes, B. W. Webb, J. Davies

Department of Mechanical Engineering, Brigham Young University, Provo, UT 84602-4201

J. Heat Transfer 130(2), 022402 (Feb 04, 2008) (8 pages) doi:10.1115/1.2789715 History: Received September 12, 2006; Revised May 15, 2007; Published February 04, 2008

This paper presents numerical results exploring the periodically repeating laminar flow thermal transport in a parallel-plate microchannel with ultrahydrophobic walls maintained at constant temperature. The walls considered here exhibit alternating microribs and cavities positioned perpendicular to the flow direction. Results describing the thermally periodically repeating dynamics far from the inlet of the channel have been obtained over a range of laminar flow Reynolds numbers and relative microrib/cavity module lengths and depths in the laminar flow regime. Previously, it has been shown that significant reductions in the overall frictional pressure drop can be achieved relative to the classical smooth channel laminar flow. The present predictions reveal that the overall thermal transport is also reduced as the relative size of the cavity region is increased. The overall Nusselt number behavior is presented and discussed in conjunction with the frictional pressure drop behavior for the parameter range explored. The following conclusions can be made regarding thermal transport for a constant temperature channel exhibiting ultrahydrophobic surfaces: (1) Increases in the relative cavity length yield decreases in the Nusselt number, (2) increasing the relative rib/cavity module length yields a decrease in the Nusselt number, and (3) decreases in the Reynolds number result in smaller values of the Nusselt number.

FIGURES IN THIS ARTICLE
<>
Copyright © 2008 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

Schematic of the near-wall and cavity regions for liquid flow over an ultrahydrophobic surface exhibiting microrib structures and bulk flow perpendicular to the ribs (13)

Grahic Jump Location
Figure 2

Schematic of the computational domain encompassing a rib/cavity module. Flow direction is from left to right (13).

Grahic Jump Location
Figure 3

Contours of the nondimensional temperature (Ts−T)∕(Ts−Tmo) in two channels where L∕Dh=0.25, Zc=1 for both channels. For the top contour plot, Fs=0.5 and Re=4, and for the bottom contour plot, Fs=0.98 and Re=1000.

Grahic Jump Location
Figure 4

Profiles of the nondimensional temperature θ at two axial positions (x∕L=0 and 0.9) for Fs=0.5 and 0.98 with Re=1000, L∕Dh=0.25, and Zc=2

Grahic Jump Location
Figure 5

Profiles of the nondimensional temperature θ at x∕L=0 and 0.9 for two Reynolds numbers Re=4 and 1000, with Fs=0.98, L∕Dh=0.25, and Zc=2

Grahic Jump Location
Figure 6

Variation of the average friction-factor Reynolds product number with Reynolds number for relative cavity lengths of Fs=0.5 and 0.98, relative microrib/cavity module lengths of L∕Dh=0.05, 0.25, and 2.5, and Zc=2 (top panel) and comparison between experimental measurement and predicted values of fRe as a function of the relative cavity length, Fs, at L∕Dh=0.25 and Re=10 (bottom panel) (13)

Grahic Jump Location
Figure 7

Variation of the average channel Nusselt number with Reynolds number for relative cavity lengths of Fs=0.5 and 0.98, relative microrib/cavity module lengths of L∕Dh=0.25 and 2.5, and Zc=2

Grahic Jump Location
Figure 8

Variation of the average channel Nusselt number with relative cavity length at Re=1000 for relative microrib/cavity module lengths of L∕Dh=0.05, 0.25, and 2.5, and Zc=2

Grahic Jump Location
Figure 9

Relative heat flux, q″∕qc″, as a function of x∕L for several scenarios all at Zc=2

Grahic Jump Location
Figure 10

Variation of ϕ∕ϕc with Re for relative cavity lengths of Fs=0.98 (top) and Fs=0.5 (bottom) for relative microrib/cavity module lengths of L∕Dh=0.05, 0.25, and 2.5, and Zc=2

Grahic Jump Location
Figure 11

Variation of ϕ∕ϕc with relative cavity length at Re=1000 for relative microrib/cavity module lengths of L∕Dh=0.05, 0.25, and 2.5, and Zc=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