Thermal analysis with comprehensive treatment of conjugate heat transfer is performed in this study for discrete flush-mounted heat sources in a horizontal channel cooled by air. The numerical model accounts for mixed convection, radiative exchange and two-dimensional conduction in the substrate. The model is first used to simulate available experimental work to demonstrate its accuracy and practical utility. A parametric study is then undertaken to assess the effects of Reynolds number, surface emissivity of walls and heat sources, as well as thickness and thermal conductivity of substrate, on flow field and heat transfer characteristics. It is shown that due to radiative heat transfer, the wall temperatures are brought closer, and the trend of temperature variation along the top wall is significantly altered. Such effects are more pronounced for higher surface emissivity and/or lower Reynolds numbers. The influence of substrate conductivity and thickness is related in that a large value of either substrate conductivity or thickness facilitates redistribution of heat and tends to yield a uniform temperature field in the substrate. For highly conductive or thick substrate, the “hot spot” cools down and may occur in upstream sources. Radiation loss to the ambient increases with substrate conductivity and thickness due to the elevated temperature near the openings, yet the total heat transfer over the bottom surface by convection and radiation remains essentially unaltered.

References

References
1.
Chu
,
R. C.
, 2004, “
The Challenges of Electronic Cooling: Past, Current and Future
,”
ASME J. Electron. Packag.
,
126
, pp.
491
500
.
2.
Morega
,
A. M.
, and
Bejan
,
A.
, 1994, “
Optimal Spacing of Parallel Boards With Discrete Heat Sources Cooled by Laminar Forced Convection
,”
Numer. Heat Transfer, Part A
,
25
, pp.
373
392
.
3.
Ortega
,
A.
, and
Ramanathan
,
S.
, 2003, “
Solutions for Forced Air Cooling of Electronic Components—Part II: Conjugate Forced Convection From a Discrete Rectangular Source on a Thin Conducting Plate
,”
ASME J. Electron. Packag.
,
125
, pp.
235
243
.
4.
Yadav
,
V.
, and
Kant
,
K.
, 2007, “
Air Cooling of Variable Array of Heated Modules in a Vertical Channel
,”
ASME J. Electron. Packag.
,
129
, pp.
205
215
.
5.
Leung
,
C. W.
, and
Kang
,
H. J.
, 1998, “
Convective Heat Transfer From Simulated Air-Cooled Printed Circuit Board Assembly on Horizontal or Vertical Orientation
,”
Int. Commun. Heat Mass Transfer
,
25
, pp.
67
80
.
6.
Dogan
,
A.
,
Sivrioglu
,
M.
, and
Baskaya
,
S.
, 2006, “
Investigation of Mixed Convection Heat Transfer in a Horizontal Channel With Discrete Heat Sources at the Top and at the Bottom
,”
Int. J. Heat Mass Transfer
,
49
, pp.
2652
2662
.
7.
Smith
,
T. F.
,
Beckermann
,
C.
, and
Weber
,
S. W.
, 1991, “
Combined Conduction, Natural Convection, and Radiation Heat Transfer in an Electronic Chassis
,”
ASME J. Electron. Packag.
,
113
, pp.
382
391
.
8.
Yu
,
E.
, and
Joshi
,
Y. K.
, 1999, “
Heat Transfer in Discretely Heated Side-Vented Compact Enclosures by Combined Conduction, Natural Convection, and Radiation
,”
ASME J. Heat Transfer
,
121
, pp.
1002
1010
.
9.
Premachandran
,
B.
, and
Balaji
,
C.
, 2006, “
Conjugate Mixed Convection With Surface Radiation From a Horizontal Channel With Protruding Heat Sources
,”
Int. J. Heat Mass Transfer
,
49
, pp.
3568
3582
.
10.
Dehghan
,
A. A.
, and
Behnia
,
M.
, 1996, “
Combined Natural Convection—Conduction and Radiation Heat Transfer in a Discretely Heated Open Cavity
,”
ASME J. Heat Transfer
,
118
, pp.
56
64
.
11.
He
,
J.
,
Liu
,
L.
, and
Jacobi
,
A. M.
, 2011, “
Numerical and Experimental Investigation of Laminar Channel Flow With a Transparent Wall
,”
ASME J. Heat Transfer
,
133
,
061701
.
12.
Chiu
,
W. K. S.
,
Richards
,
C. J.
, and
Jaluria
,
Y.
, 2001, “
Experimental and Numerical Study of Conjugate Heat Transfer in a Horizontal Channel Heated From Below
,”
ASME J. Heat Transfer
,
123
, pp.
688
697
.
13.
Incropera
,
F. P.
, and
DeWitt
,
D. P.
, 2002,
Fundamentals of Heat and Mass Transfer, 5th ed.
,
Wiley, Hoboken, NJ
.
14.
Liu
,
C. H.
, and
Sparrow
,
E. M.
, 1980, “
Convective-Radiative Interaction in a Parallel Plate Channel—Application to Air-Operated Solar Collectors
,”
Int. J. Heat Mass Transfer
,
23
, pp.
1137
1146
.
15.
Siegel
,
R.
, and
Howell
,
J.
, 2002,
Thermal Radiation Heat Transfer, 4th ed.
,
Taylor & Francis
,
New York.
16.
Press
,
W. H.
,
Teukolsky
,
S. A.
,
Vetterling
,
W. T.
, and
Flannery
,
B. P.
, 1996
, Numerical Recipes in Fortran, 2nd ed., Cambr
idge
University
,
New York.
17.
McEntire
,
A. B.
, and
Webb
,
B. W.
, 1990, “
Local Forced Convective Heat Transfer From Protruding and Flush-Mounted Two-Dimensional Discrete Heat Sources
,”
Int. J. Heat Mass Transfer
,
33
, pp.
1521
1533
.
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