Nanofluids are colloidal solutions, which contain a small volume fraction of suspended submicron particles or fibers in heat transfer liquids such as water or glycol mixtures. Compared with the base fluid, numerous experiments have generally indicated an increase in effective thermal conductivity and a strong temperature dependence of the static effective thermal conductivity. However, in practical applications, a heat conduction mechanism may not be sufficient for cooling high heat dissipation devices such as microelectronics or powerful optical equipment. Thus, thermal performance under convective heat transfer conditions becomes of primary interest. We report here the heat transfer coefficient h in both developing and fully developed regions by using water-based alumina nanofluids. Our experimental test section consists of a single 1.02-mm diameter stainless steel tube, which is electrically heated to provide a constant wall heat flux. Both pressure drop and temperature differences are measured, but mostly here we report our h measurements under laminar flow conditions. An extensive characterization of the nanofluid samples, including pH, electrical conductivity, particle sizing, and zeta potential, is also documented. The measured h values for nanofluids are generally higher than those for pure water. In the developing region, this can be at least partially explained by Pr number effects.

1.
Choi
,
S. U. S.
, 1995, “
Enhancing Thermal Conductivity of Fluids With Nanoparticles
,”
Developments and Applications of Non-Newtonian Flows
,
ASME
,
New York
, Vol.
231
, pp.
99
105
.
2.
Lee
,
S.
,
Choi
,
S. U. S.
,
Li
,
S.
, and
Eastman
,
J. A.
, 1999, “
Measuring Thermal Conductivity of Fluids Containing Oxide Nanoparticles
,”
ASME J. Heat Transfer
0022-1481,
121
, pp.
280
289
.
3.
Eastman
,
J. A.
,
Choi
,
S. U. S.
,
Li
,
S.
,
Yu
,
W.
, and
Thompson
,
L. J.
, 2001, “
Anomalously Increased Effective Thermal Conductivities of Ethylene Glycol-Based Nanofluids Containing Copper Nanoparticles
,”
Appl. Phys. Lett.
0003-6951,
78
(
6
), pp.
718
720
.
4.
Kumar
,
D. H.
,
Patel
,
H. E.
,
Kumar
,
V. R. R.
,
Pradeep
,
T.
, and
Das
,
S. K.
, 2004, “
Model for Heat Conduction in Nanofluids
,”
Phys. Rev. Lett.
0031-9007,
93
(
14
), p.
144301
.
5.
Hong
,
K. S.
,
Hong
,
T. K.
, and
Yang
,
H. S.
, 2006, “
Thermal Conductivity of Fe Nanofluids Depending on the Cluster Size of Nanoparticles
,”
Appl. Phys. Lett.
0003-6951,
88
, p.
031901
.
6.
Putnam
,
S. A.
,
Cahill
,
D. G.
, and
Braun
,
P. V.
, 2006, “
Thermal Conductivity of Nanoparticle Suspensions
,”
J. Appl. Phys.
0021-8979,
99
, p.
084308
.
7.
Rusconi
,
R.
,
Rodari
,
E.
, and
Piazza
,
R.
, 2006, “
Optical Measurements of the Thermal Properties of Nanofluids
,”
Appl. Phys. Lett.
0003-6951,
89
, p.
261916
.
8.
Prasher
,
R.
,
Evans
,
W.
,
Meakin
,
P.
,
Fish
,
J.
,
Phelan
,
P.
, and
Keblinski
,
P.
, 2006, “
Effect of Aggregation on Thermal Conduction in Colloidal Nanofluids
,”
Appl. Phys. Lett.
0003-6951,
89
, p.
143119
.
9.
Keblinski
,
P.
, and
Thomin
,
J.
, 2006, “
Hydrodynamic Field Around a Brownian Particle
,”
Phys. Rev. E
1063-651X,
73
, p.
010502
.
10.
Eapen
,
J.
,
Williams
,
W. C.
,
Buongiorno
,
J.
,
Hu
,
L. W.
, and
Yip
,
S.
, 2007, “
Mean-Field Versus Microconvection Effects in Nanofluid Thermal Conduction
,”
Phys. Rev. Lett.
0031-9007,
99
, p.
095901
.
11.
Sarkar
,
S.
, and
Selvam
,
R. P.
, 2007, “
Molecular Dynamics Simulation of Effective Thermal Conductivity and Study of Enhanced Thermal Transport Mechanism in Nanofluids
,”
J. Appl. Phys.
0021-8979,
102
, p.
074302
.
12.
Keblinski
,
P.
,
Eastman
,
J. A.
, and
Cahill
,
D. G.
, 2005, “
Nanofluids for Thermal Transport
,”
Mater. Today
1369-7021,
8
(
6
), pp.
36
44
.
13.
Das
,
S. K.
,
Choi
,
S. U. S.
, and
Patel
,
H. E.
, 2006, “
Heat Transfer in Nanofluids—A Review
,”
Heat Transfer Eng.
0145-7632,
27
, pp.
3
19
.
14.
Wang
,
X. Q.
, and
Mujumdar
,
A. S.
, 2007, “
Heat Transfer Characteristics of Nanofluids: A Review
,”
Int. J. Therm. Sci.
1290-0729,
46
, pp.
1
19
.
15.
Trisaksri
,
V.
, and
Wongwises
,
S.
, 2007, “
Critical Review of Heat Transfer Characteristics of Nanofluids
,”
Renewable Sustainable Energy Rev.
1364-0321,
11
, pp.
512
523
.
16.
Daungthongsuk
,
W.
, and
Wongwises
,
S.
, 2007, “
A Critical Review of Convective Heat Transfer of Nanofluids
,”
Renewable Sustainable Energy Rev.
1364-0321,
11
, pp.
797
817
.
17.
Ahuja
,
A. S.
, 1975, “
Augmentation of Heat Transport in Laminar Flow of Polystyrene Suspensions. I. Experiments and Results
,”
J. Appl. Phys.
0021-8979,
46
(
8
), pp.
3408
3416
.
18.
Ahuja
,
A. S.
, 1975, “
Augmentation of Heat Transport in Laminar Flow of Polystyrene Suspensions. II. Analysis of the Data
,”
J. Appl. Phys.
0021-8979,
46
(
8
), pp.
3417
3425
.
19.
Pak
,
B. C.
, and
Cho
,
Y. I.
, 1998, “
Hydrodynamic and Heat Transfer Study of Dispersed Fluids With Submicron Metallic Oxide Particles
,”
Exp. Heat Transfer
0891-6152,
11
(
2
), pp.
151
170
.
20.
Xuan
,
Y.
, and
Li
,
Q.
, 2003, “
Investigation on Convective Heat Transfer and Flow Features of Nanofluids
,”
ASME J. Heat Transfer
0022-1481,
125
, pp.
151
155
.
21.
Wen
,
D.
, and
Ding
,
Y.
, 2004, “
Experimental Investigation Into Convective Heat Transfer of Nanofluids at the Entrance Region Under Laminar Flow Conditions
,”
Int. J. Heat Mass Transfer
0017-9310,
47
, pp.
5181
5188
.
22.
Ding
,
Y.
,
Alias
,
H.
,
Wen
,
D.
, and
Williams
,
R. A.
, 2006, “
Heat Transfer of Aqueous of Carbon Nanotubes (CNT Nanofluids)
,”
Int. J. Heat Mass Transfer
0017-9310,
49
, pp.
240
250
.
23.
He
,
Y.
,
Jin
,
Y.
,
Chen
,
H.
,
Ding
,
Y.
,
Chang
,
D.
, and
Lu
,
H.
, 2007, “
Heat Transfer and Flow Behaviour of Aqueous Suspensions of TiO2 Nanoparticles (Nanofluids) Flowing Upward Through a Vertical Pipe
,”
Int. J. Heat Mass Transfer
0017-9310,
50
, pp.
2272
2281
.
24.
Yang
,
Y.
,
Zhang
,
Z. G.
,
Grulke
,
E. A.
,
Anderson
,
W. B.
, and
Wu
,
G.
, 2005, “
Heat Transfer Properties of Nanoparticle-in-Fluid Dispersions (Nanofluids) in Laminar Flow
,”
Int. J. Heat Mass Transfer
0017-9310,
48
, pp.
1107
1116
.
25.
Heris
,
S. Z.
,
Esfahany
,
M. N.
, and
Etemad
,
G.
, 2006, “
Investigation of CuO/Water Nanofluid Laminar Convective Heat Transfer Through a Circular Tube
,”
J. Enhanced Heat Transfer
1065-5131,
13
(
4
), pp.
279
289
.
26.
Heris
,
S. Z.
,
Esfahany
,
M. N.
, and
Etemad
,
S. Gh.
, 2007, “
Experimental Investigation of Convective Heat Transfer of Al2O3/Water Nanofluid in Circular Tube
,”
Int. J. Heat Fluid Flow
0142-727X,
28
(
2
), pp.
203
210
.
27.
Nguyen
,
C. T.
,
Roy
,
G.
,
Gauthier
,
C.
, and
Galanis
,
N.
, 2007, “
Heat Transfer Enhancement Using Al2O3-Water Nanofluid for an Electronic Liquid Cooling System
,”
Appl. Therm. Eng.
1359-4311,
27
, pp.
1501
1506
.
28.
Chein
,
R.
, and
Chuang
,
J.
, 2007, “
Experimental Microchannel Heat Sink Performance Studies Using Nanofluids
,”
Int. J. Therm. Sci.
1290-0729,
46
(
1
), pp.
57
66
.
29.
Lee
,
J.
,
Flynn
,
R. D.
,
Goodson
,
K. E.
, and
Eaton
,
J. K.
, 2007, “
Convective Heat Transfer of Nanofluids (DI Water-Al2O3) in Micro-Channels
,” ASME Paper No. HT2007-32630.
30.
Lai
,
W. Y.
,
Duculescu
,
B.
,
Phelan
,
P. E.
,
Prasher
,
R.
, 2006, “
A Review of Convective Heat Transfer With Nanofluids for Electronics Packaging
,”
ITHERM 06
, pp.
1240
1244
.
31.
Hunter
,
R. J.
, 2004,
Foundations of Colloid Science
,
2nd ed.
,
Oxford University Press
,
New York
.
32.
Incropera
,
F. P.
, and
DeWitt
,
D. P.
, 1996,
Fundamentals of Heat and Mass Transfer
,
Wiley
,
New York
.
33.
Figliola
,
R. S.
, and
Beasley
,
D. E.
, 2005,
Theory and Design for Mechanical Measurements
,
4th ed.
,
Wiley
,
New York
.
34.
Kays
,
W. M.
, and
Crawford
,
M. E.
, 1993,
Convective Heat and Mass Transfer
,
McGraw-Hill
,
New York
.
35.
Prasher
,
R.
,
Song
,
D.
,
Wang
,
J.
, and
Phelan
,
P.
, 2006, “
Measurements of Nanofluids Viscosity and its Implications for Thermal Applications
,”
Appl. Phys. Lett.
0003-6951,
89
, p.
133108
.
36.
Buongiorno
,
J.
, 2006, “
Convective Transport in Nanofluids
,”
ASME J. Heat Transfer
0022-1481,
128
, pp.
240
250
.
37.
Mills
,
P.
, and
Snabre
,
P.
, 1995, “
Rheology and Structure of Concentrated Suspensions of Hard Spheres, Shear Induced Particle Migration
,”
J. Phys. II
1155-4312,
5
, pp.
1597
1608
.
38.
Sohn
,
C. W.
, and
Chen
,
M. M.
, 1984, “
Heat Transfer Enhancement in Laminar Slurry Pipe Flow With Power Law Thermal Conductivities
,”
ASME J. Heat Transfer
0022-1481,
106
, pp.
539
542
.
39.
Williams
,
W.
,
Buongiorno
,
J.
, and
Hu
,
L. W.
, 2008, “
Experimental Investigation of Turbulent and Pressure Loss of Alumina/Water and Zirconia/Water Nanoparticle Colloids (Nanofluids) in Horizontal Tubes
,”
ASME J. Heat Transfer
0022-1481,
130
, p.
042412
.
You do not currently have access to this content.