Forced convection heat transfer from a low-profile block placed in a rectangular duct, simulating heat transfer in a compact packaged electronic device, is investigated experimentally. Local heat transfer from the block is measured by an infrared camera. A general correlation of the Nusselt number for the block is derived using a modified Reynolds number, $ReL*=Um/β2L/ν,$ where $Um$ is mean duct velocity, β is the opening ratio of the duct, and L is the block length. The correlation is shown to be applicable regardless of the configuration of the block and duct, under the conditions of laminar flow, a low-profile block (height/length<0.5), and a low blockage effect (β⩾0.5).

1.
Peterson, G. P., and Ortega, A., 1990, Advances in Heat Transfer, Academic Press, pp. 181–314.
2.
Roeller
,
P. T.
,
Stevens
,
J.
, and
Webb
,
B. W.
,
1991
, “
Heat Transfer and Turbulent Flow Characteristics of Isolated Three-Dimensional Protrusions in Channels
,”
ASME J. Heat Transfer
,
113
, pp.
597
603
.
3.
Takasaki, H., 1992, “Fluid Flow and Heat Transfer Around Rectangular Protrusions,” Ph.D. thesis (in Japanese), Tokyo Institute of Technology, Japan.
4.
Nakayama
,
W.
, and
Park
,
S. H.
,
1996
, “
Conjugate Heat Transfer From a Single Surface-Mounted Block to Forced Convective Air Flow in a Channel
,”
ASME J. Heat Transfer
,
118
, pp.
301
309
.
5.
Young
,
T. J.
, and
Vafai
,
K.
,
1998
, “
Convective Cooling of a Heated Obstacle in a Channel
,”
Int. J. Heat Mass Transfer
,
41
, pp.
3131
3148
.
6.
Nakayama, W., 2001, “An Approach to Fast Thermal Design of Compact Electronic Systems: A JSME Project,” Proc. InterPACK, Kauai, Hawaii, Paper No. IPACK2001-15532, ASME, NY.
7.
Nakamura
,
H.
,
Igarashi
,
T.
, and
Tsutsui
,
T.
,
2001
, “
Local Heat Transfer Around a Wall-Mounted Cube in the Turbulent Boundary Layer
,”
Int. J. Heat Mass Transfer
,
44
, pp.
3385
3395
.
8.
Pellow
,
A.
, and
Southwell
,
R. V.
,
1940
, “
On Maintained Convective Motion in a Fluid Heated From Below
,”
Proc. R. Soc. London, Ser. A
,
176
, pp.
312
343
.
9.
Shah, R. K., and London, A. L., 1978, Laminar Flow Forced Convection in Ducts, New York Academic Press, pp. 153–195.
10.
Lehmann
,
G. L.
, and
Pembroke
,
J.
,
1991
, “
Forced Convection Air Cooling of Simulated Low Profile Electronic Components: Part 1—Base Case
,”
ASME J. Electron. Packag.
,
113
, pp.
21
26
.
11.
Igarashi, T., and Takasaki, H., 1995, “Fluid Flow and Heat Transfer Around a Rectangular Block Fixed on a Flat Plate Laminar Boundary Layer,” Proc. 4th ASME/JSME Thermal Engineering Joint Conf., ASME/JSME, NY/Tokyo, Japan, 1, pp. 295–302.
12.
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
(
7
), pp.
1521
1533
.
13.
Kang
,
B. H.
,
Jaluria
,
Y.
, and
Tewari
,
S. S.
,
1990
, “
Mixed Convection Transport From an Isolated Heat Source Module on a Horizontal Plate
,”
ASME J. Heat Transfer
,
112
, pp.
653
661
.
14.
Young
,
T. J.
, and
Vafai
,
K.
,
1999
, “
Experimental and Numerical Investigation of Forced Convective Characteristics of Arrays of Channel Mounted Obstacles
,”
ASME J. Heat Transfer
,
121
, pp.
34
42
.
15.
Mahaney
,
H. V.
,
Incropera
,
F. P.
, and
,
S.
,
1990
, “
Comparison of Predicted and Measured Mixed Convection Heat Transfer From an Array of Discrete Sources in a Horizontal Rectangular Channel
,”
Int. J. Heat Mass Transfer
,
33
(
6
), pp.
1233
1245
.
16.
Garimella
,
S. V.
, and
Eibeck
,
P. A.
,
1990
, “
Heat Transfer Characteristics of an Array of Protruding Elements in Single Phase Forced Convection
,”
Int. J. Heat Mass Transfer
,
33
(
12
), pp.
2659
2669
.
17.
Davalath
,
J.
, and
Bayazitoglu
,
Y.
,
1987
, “
Forced Convection Cooling Across Rectangular Blocks
,”
ASME J. Heat Transfer
,
109
, pp.
321
328
.