Research Papers

Pool Boiling Heat Transfer Enhancement Through Nanostructures on Silicon Microchannels

[+] Author and Article Information
Z. Yao

Rochester Institute of Technology,
Rochester, NY 14623

Y.-W. Lu

Department of Bio-Industrial
Mechatronics Engineering,
National Taiwan University,
Taipei, 10617, Taiwan

S. G. Kandlikar

Mechanical Engineering Department,
Rochester Institute of Technology,
Rochester, NY 14623
e-mail: sgkeme@rit.edu

1Corresponding author.

Manuscript received March 4, 2012; final manuscript received August 2, 2012; published online January 18, 2013. Assoc. Editor: Debjyoti Banerjee.

J. Nanotechnol. Eng. Med 3(3), 031002 (Jan 18, 2013) (8 pages) doi:10.1115/1.4007425 History: Received March 04, 2012; Revised August 02, 2012

Uniform silicon nanowires (SiNW) were successfully fabricated on the top, bottom, and sidewall surfaces of silicon microchannels by using a two-step electroless etching process. Different microchannel patterns with the channel width from 100 to 300 μm were first fabricated in a 10 mm × 10 mm silicon chip and then covered by SiNW with an average height of 10–20 μm. The effects of the microchannel geometry, micro/nano-hierarchical structures on pool boiling were studied and the bubble dynamics on different sample surfaces were compared. It was found that the combination of the micro/nanostructures promoted microbubble emission boiling under moderate heat fluxes, and yielded superior boiling heat transfer performance. At given wall superheats, the maximum heat flux of the microchannel with SiNW was improved by 120% over the microchannel-only surface, and more than 400% over a plain silicon surface. These results provide a new insight into the boiling mechanism for micro/nano-hierarchical structures and demonstrate their potential in improving pool boiling performance for microchannels.

Copyright © 2013 by ASME
Your Session has timed out. Please sign back in to continue.



Grahic Jump Location
Fig. 1

Microchannel dimensions

Grahic Jump Location
Fig. 2

(a) and (b) Microchannel fabrication process flow, (c) and (d) SiNW synthesis on microchannel

Grahic Jump Location
Fig. 3

SEM images of SiNW at (a) microchannel sidewall area, (b) top area, (c) fin area, and (d) bottom area after two-step etching process

Grahic Jump Location
Fig. 4

Contact angles of (a) and (b) sample #2 (100 μm fin width) at X and Y directions, (c) sample #2 with SiNW, (d) and (e) sample #6 (200 μm fin width) at X and Y direction, (f) sample #6 with SiNW, (g)–(h) sample #7 (300 μm fin width) at X and Y direction, and (i) sample #7 with SiNW

Grahic Jump Location
Fig. 5

Schematic of boiling test fixture (a) cartridge heater, (b) ceramic block, (c) testing chip, (d) gasket, (e) polycarbonate visualization tube, (f) auxiliary heater, (g) K-type thermocouples, (h) data acquisition system, (i) compression screws, (j) high speed camera, and (k) power supply

Grahic Jump Location
Fig. 6

Boiling curves for microchannels with and without SiNW: (a) samples# 1–3, (b) samples# 4–6, and (c) samples# 7–9

Grahic Jump Location
Fig. 7

Heat transfer coefficient for the SiNW samples and plain surface

Grahic Jump Location
Fig. 8

Successive images of bubble generation at low heat flux (10–15 W/cm2) on the samples of (a) and (b) microchannel-only and (d) and (e) microchannel with SiNW at 0.02 s intervals; (c) and (f) illustrate the possible mechanisms of bubble generations on microchannel-only and microchannel with SiNW surface, respectively

Grahic Jump Location
Fig. 9

Successive images of (a)–(d) microbubble emission boiling at intermediate heat flux (60–80 W/cm2) at 0.1 s interval and (e)–(h) large bubble generation at high heat flux (120–140 W/cm2) at 0.02 s interval for microchannel with SiNW surface




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