0
Research Papers: Heat Transfer Enhancement

Flow and Heat Transfer in Microchannels With Dimples and Protrusions

[+] Author and Article Information
Jibing Lan, Di Zhang

School of Energy and Power Engineering,  Xi’an Jiaotong University, Xi’an, Shaanxi Province, 710049, Chinayhxie@mail.xjtu.edu.cn

Yonghui Xie1

School of Energy and Power Engineering,  Xi’an Jiaotong University, Xi’an, Shaanxi Province, 710049, Chinayhxie@mail.xjtu.edu.cn

1

Corresponding author.

J. Heat Transfer 134(2), 021901 (Dec 09, 2011) (9 pages) doi:10.1115/1.4005096 History: Received November 16, 2010; Accepted September 06, 2011; Published December 09, 2011; Online December 09, 2011

Flow characteristics and heat transfer performances in a rectangular microchannel with dimples/protrusions are studied numerically in this research. The height and the width of the microchannel is 200 μm and 50 μm, respectively. The dimple/protrusion diameter is 100 μm, and the depth is 20 μm. The effects of Reynolds number, streamwise pitch, and arrangement pattern are examined. The numerical simulations are conducted using water as the coolant with the Reynolds number ranging from 100 to 900. The results show that dimple/protrusion technique in mcirochannel has the potential to provide heat transfer enhancement with low pressure penalty. The normalized Nusselt number is within the range from 1.12 to 4.77, and the corresponding normalized friction factor is within the range from 0.94 to 2.03. The thermal performance values show that the dimple + protrusion cases perform better than the dimple + smooth cases. The flow characteristics of the dimples/protrusions in microchannel are similar to those in conventional channel. Furthermore, from the viewpoint of energy saving, dimples/protrusions in microchannel behave better than those in conventional channel. Also from the viewpoint of field synergy principle, the synergy of the dimple + protrusion cases are much better than the dimple + smooth cases. Moreover, the synergy becomes worse with the increase in the Reynolds number and decrease in the streamwise pitch.

FIGURES IN THIS ARTICLE
<>
Copyright © 2012 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 diagrams of: (a) over view microchannels and dimple arrangement, (b) cross-sectional view of dimple/protrusion, (c) side view of the staggered dimpled surface of the mircochannel (P ≠ 0), and (d) side view of the nonstaggered dimpled surface (P = 0)

Grahic Jump Location
Figure 2

Coordinate system and details of the computational domain: (a) case 1 and (b) case 7

Grahic Jump Location
Figure 3

Heat transfer and friction characteristics: (a) Nu/Nu0 variations with Reynolds number and (b) f/f0 variations with Reynolds number

Grahic Jump Location
Figure 4

Comparison of the increase of form and decrease of friction loss

Grahic Jump Location
Figure 5

Thermal performance variations with Reynolds number

Grahic Jump Location
Figure 6

Limiting stream lines and temperature contours on the dimpled surface of case 2: (a) Re = 100 and (b) Re = 700

Grahic Jump Location
Figure 7

Limiting stream lines and temperature contours on the dimpled surface of case 4: (a) Re = 100 and (b) Re = 700

Grahic Jump Location
Figure 8

Limiting stream lines and temperature contours on the dimpled surface of case 7: (a) dimple, Re = 100, (b) protrusion, Re = 100, (c) dimple, Re = 700, and (d) protrusion, Re = 700

Grahic Jump Location
Figure 9

Limiting stream lines and temperature contours on the dimpled surface of case 10: (a) dimple, Re = 100, (b) protrusion, Re = 100, (c) dimple, Re = 700, and (d) protrusion, Re = 700

Grahic Jump Location
Figure 10

Compare the performances of the dimples in microchannels with those in conventional channel

Grahic Jump Location
Figure 11

[ave cos(θ)] variations with Reynolds number

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