Abstract

The increased importance of heat sinks in electronic cooling applications has resulted in a revived interest in extended surfaces, or fins. Also, space and cost constraints provide impetus for optimizing thermal performance for a given, or least, amount of material. The current research focuses on a pin fin design of least material, where the diameter of the pin fin varies axially to maintain the axial heat flux constant; thus all fin material is utilized equally. Although such fins have been studied in the past, the convective heat transfer coefficient was assumed to be constant, which is not entirely true since it is known to be a function of diameter for cylindrical bodies. The current research shows that an optimal fin based on a variable convective heat transfer coefficient yields a true optimal profile, and utilizes material better; that is, it uses a lower volume of material to achieve the same heat dissipation rate. This improvement in material utilization is show to be anywhere from approximately 3% to 14%.

References

1.
Kern
,
D. Q.
, and
Kraus
,
A. D.
, 1972,
Extended Surface Heat Transfer
,
McGraw-Hill
,
New York
, Chap. 2.
2.
Kraus
,
A. D.
, 1988, “
Sixty-Five Years of Extended Surface Technology
,”
Appl. Mech. Rev.
0003-6900,
41
, pp.
321
364
.
3.
Eckert
,
E. R. G.
, and
Drake
,
R. M.
, Jr.
, 1972,
Analyses of Heat and Mass Transfer
,
McGraw-Hill
,
New York
, Chaps. 3 and 9.
4.
Schmidt
,
E.
, 1926, “
Die Warmeubertragung Durch Rippen
,”
Z. Ver. Deut. Ingenieure
,
70
, pp.
885
889
;
Schmidt
,
E.
, 1926, “
Die Warmeubertragung Durch Rippen
,”
Z. Ver. Deut. Ingenieure
,
70
,pp.
947
951
.
5.
Snider
,
A. D.
, and
Kraus
,
A. D.
, 1986, “
The Quest for the Optimum Longitudinal Fin Profile
,”
ASME HTD
,
64
, pp.
43
48
.
6.
Chung
,
B. T. F.
,
Talbot
,
D. J.
, and
Van Dyke
,
J. M.
, “
A New Look at the Optimum Dimensions of Convective Splines
,”
AIChE Heat Transfer
,
84
, pp.
108
113
(1988).
7.
Aziz
,
A.
, 1992, “
Optimal Dimensions of Extended Surfaces Operations in a Convective Environment
,”
Appl. Mech. Rev.
0003-6900,
45
, pp.
155
173
.
8.
Sonn
,
A.
, and
Bar-Cohen
,
A.
, 1981, “
Optimum Cylindrical Pin Fin
,”
ASME J. Heat Transfer
0022-1481,
103
, pp.
814
815
.
9.
Li
,
C. H.
, 1983, “
Optimum Cylindrical Pin Fin
,”
AIChE J.
0001-1541,
29
, pp.
1043
1044
.
10.
Holman
,
J. P.
, 1981,
Heat Transfer
, 5th ed.,
McGraw-Hill
,
New York
, Chap. 6.
11.
Hanin
,
L.
, and
Campo
,
A.
, 2003, “
A New Minimum Volume Straight Cooling Fin Taking Into Account the ‘Length of Arc’
,”
Int. J. Heat Mass Transfer
0017-9310,
46
, pp.
5145
5152
.
12.
Chung
,
B. T. F.
, and
Iyer
,
J. R.
, 1993, “
Optimum Design of Longitudinal Rectangular Fins and Cylindrical Spines With Variable Heat Transfer Coefficient
,”
Heat Transfer Eng.
0145-7632,
14
, pp.
31
42
.
13.
McAdams
,
W. H.
, 1954,
Heat Transmission
, 3rd ed.,
McGraw-Hill
,
New York
.
14.
Morgan
,
V. T.
, 1975, “
The Overall Convective Heat Transfer From Smooth Circular Cylinder
,”
Advances in Heat Transfer
,
T. F.
Irvine
and
J. P.
Hartnett
, eds.,
Academic Press
,
New York
, Vol.
11
.
15.
Kobus
,
C. J.
, 2005, “
A Material Utilization Factor for Quantifying the Performance of Optimal Shape Extended Surfaces of Minimum Volume
,”
Proceeding of the 2005 ASME International Mechanical Engineering Congress and R&D Expo (IMECE)
,
Orlando, FL
, November 5–11.
16.
Kobus
,
C. J.
, and
Oshio
,
T.
, 2005, “
Development of a Theoretical Model for Predicting the Thermal Performance Characteristics of a Vertical Pin-Fin Array Heat Sink under Combined Forced and Natural Convection With Impinging Flow
,”
Int. J. Heat Mass Transfer
0017-9310,
48
, pp.
1053
1063
.
17.
Kobus
,
C. J.
, and
Oshio
,
T.
, 2005, “
Predicting the Thermal Performance Characteristics of Staggered Vertical Pin-Fin Array Heat Sinks Under Combined Mode Radiation and Mixed Convection With Impinging Flow
,”
Int. J. Heat Mass Transfer
0017-9310,
48
(
13
), pp.
2684
2696
.
18.
Kobus
,
C. J.
, and
Oshio
,
T.
, 2006, “
Thermal Performance Characteristics of a Staggered Vertical Pin Fin Array Heat Sink With Assisting Mixed Convection in External and In-Duct Flow Configurations
,”
Exp. Heat Transfer
0891-6152
19
(
2
), pp.
129
148
.
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