We show that heat transfer in microchannels can be considerably augmented by introducing droplets or slugs of an immiscible liquid into the main fluid flow. We numerically investigate the influence of differently shaped colloidal or simply pure immiscible droplets to the main liquid flow on the thermal transport in microchannels. Results of parametric studies on the influence of all major factors connected to microchannel heat transfer are presented. The effect of induced Marangoni flow at the liquid interfaces is also taken into account and quantified. The calculation of the multiphase, multispecies flow problem is performed, applying a front tracking method, extended to account for nanoparticle transport in the suspended phase when relevant. This study reveals that the use of a second suspended liquid (with or without nanoparticles) is an efficient way to significantly increase the thermal performance without unacceptably large pressure losses. In the case of slug-train coflow, the Nusselt number can be increased by as much as 400% compared with single liquid flow.

1.
Escher
,
W.
,
Michel
,
B.
, and
Poulikakos
,
D.
, 2009, “
Efficiency of Optimized Bifurcating Tree-Like and Parallel Microchannel Networks in the Cooling of Electronics
,”
Int. J. Heat Mass Transfer
0017-9310,
52
(
5–6
), pp.
1421
1430
.
2.
Senn
,
S. M.
, and
Poulikakos
,
D.
, 2004, “
Laminar Mixing, Heat Transfer and Pressure Drop in Tree-Like Microchannel Nets and Their Application for Thermal Management in Polymer Electrolyte Fuel Cells
,”
J. Power Sources
0378-7753,
130
(
1–2
), pp.
178
191
.
3.
Senn
,
S. M.
, and
Poulikakos
,
D.
, 2004, “
Polymer Electrolyte Fuel Cells With Porous Materials as Fluid Distributors and Comparisons With Traditional Channeled Systems
,”
ASME J. Heat Transfer
0022-1481,
126
(
3
), pp.
410
418
.
4.
Senn
,
S. M.
, and
Poulikakos
,
D.
, 2004, “
Tree Network Channels as Fluid Distributors Constructing Double-Staircase Polymer Electrolyte Fuel Cells
,”
J. Appl. Phys.
0021-8979,
96
(
1
), pp.
842
852
.
5.
Keblinski
,
P.
,
Phillpot
,
S. R.
,
Choi
,
S. U. S.
, and
Eastman
,
J. A.
, 2002, “
Mechanisms of Heat Flow in Suspensions of Nano-Sized Particles (Nanofluids)
,”
Int. J. Heat Mass Transfer
0017-9310,
45
(
4
), pp.
855
863
.
6.
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
(
2
), pp.
280
289
.
7.
Shalkevich
,
N.
,
Escher
,
W.
,
Buergi
,
T.
,
Michel
,
B.
,
Si-Ahmed
,
L.
, and
Poulikakos
,
D.
, 2010, “
On the Thermal Conductivity of Gold Nanoparticle Colloids
,”
Langmuir
0743-7463,
26
(
2
), pp.
663
670
.
8.
Keblinski
,
P.
,
Eastman
,
J. A.
, and
Cahill
,
D. G.
, 2005, “
Nanofluids for Thermal Transport
,”
Mater. Today
1369-7021,
8
(
6
), pp.
36
44
.
9.
Wang
,
X. Q.
, and
Mujumdar
,
A. S.
, 2007, “
Heat Transfer Characteristics of Nanofluids: A Review
,”
Int. J. Therm. Sci.
1290-0729,
46
(
1
), pp.
1
19
.
10.
Yu
,
W.
,
France
,
D. M.
,
Routbort
,
J. L.
, and
Choi
,
S. U. S.
, 2008, “
Review and Comparison of Nanofluid Thermal Conductivity and Heat Transfer Enhancement
,”
Heat Transfer Eng.
0145-7632,
29
(
5
), pp.
432
460
.
11.
Buongiorno
,
J.
,
Venerus
,
D. C.
,
Prabhat
,
N.
,
McKrell
,
T.
,
Townsend
,
J.
,
Christianson
,
R.
,
Tolmachev
,
Y. V.
,
Keblinski
,
P.
,
Hu
,
L. -w.
,
Alvarado
,
J. L.
,
Bang
,
I. C.
,
Bishnoi
,
S. W.
,
Bonetti
,
M.
,
Botz
,
F.
,
Cecere
,
A.
,
Chang
,
Y.
,
Chen
,
G.
,
Chen
,
H.
,
Chung
,
S. J.
,
Chyu
,
M. K.
,
Das
,
S. K.
,
Di Paola
,
R.
,
Ding
,
Y.
,
Dubois
,
F.
,
Dzido
,
G.
,
Eapen
,
J.
,
Escher
,
W.
,
Funfschilling
,
D.
,
Galand
,
Q.
,
Gao
,
J.
,
Gharagozloo
,
P. E.
,
Goodson
,
K. E.
,
Gutierrez
,
J. G.
,
Hong
,
H.
,
Horton
,
M.
,
Hwang
,
K. S.
,
Iorio
,
C. S.
,
Jang
,
S. P.
,
Jarzebski
,
A. B.
,
Jiang
,
Y.
,
Jin
,
L.
,
Kabelac
,
S.
,
Kamath
,
A.
,
Kedzierski
,
M. A.
,
Kieng
,
L. G.
,
Kim
,
C.
,
Kim
,
J. -H.
,
Kim
,
S.
,
Lee
,
S. H.
,
Leong
,
K. C.
,
Manna
,
I.
,
Michel
,
B.
,
Ni
,
R.
,
Patel
,
H. E.
,
Philip
,
J.
,
Poulikakos
,
D.
,
Reynaud
,
C.
,
Savino
,
R.
,
Singh
,
P. K.
,
Song
,
P.
,
Sundararajan
,
T.
,
Timofeeva
,
E.
,
Tritcak
,
T.
,
Turanov
,
A. N.
,
Van Vaerenbergh
,
S.
,
Wen
,
D.
,
Witharana
,
S.
,
Yang
,
C.
,
Yeh
,
W. -H.
,
Zhao
,
X. -Z.
, and
Zhou
,
S. -Q.
, 2009, “
A Benchmark Study on the Thermal Conductivity of Nanofluids
,”
J. Appl. Phys.
0021-8979,
106
(
9
), pp.
094312
.
12.
Lakehal
,
D.
,
Larrignon
,
G.
, and
Narayanan
,
C.
, 2008, “
Computational Heat Transfer and Two-Phase Flow Topology in Miniature Tubes
,”
Microfluid. Nanofluid.
1613-4982,
4
(
4
), pp.
261
271
.
13.
Fukagata
,
K.
,
Kasagi
,
N.
,
Ua-arayaporn
,
P.
, and
Himeno
,
T.
, 2005, “
Numerical Simulation of Gas-Liquid Two-Phase Flow and Convective Heat Transfer in a Micro Tube
,”
International Conference on Heat Transfer and Fluid Flow in Microscale
,
Elsevier Science
,
Barga, Italy
, pp.
72
82
.
14.
Urbant
,
P.
,
Leshansky
,
A.
, and
Halupovich
,
Y.
, 2008, “
On the Forced Convective Heat Transport in a Droplet-Laden Flow in Microchannels
,”
Microfluid. Nanofluid.
1613-4982,
4
(
6
), pp.
533
542
.
15.
Monde
,
M.
, and
Mitsutake
,
Y.
, 1995, “
Enhancement of Heat Transfer Due to Bubbles Passing Through a Narrow Vertical Rectangular Channel (Change in Heat Transfer Along Flow)
,”
Heat Mass Transfer
0947-7411,
31
(
1–2
), pp.
77
82
.
16.
Joanicot
,
M.
, and
Ajdari
,
A.
, 2005, “
Applied Physics-Droplet Control for Microfluidics
,”
Science
0036-8075,
309
(
5736
), pp.
887
888
.
17.
Cubaud
,
T.
, and
Mason
,
T. G.
, 2008, “
Capillary Threads and Viscous Droplets in Square Microchannels
,”
Phys. Fluids
0031-9171,
20
(
5
), p.
053302
.
18.
Xu
,
J. H.
,
Li
,
S. W.
,
Tan
,
J.
,
Wang
,
Y. J.
, and
Luo
,
G. S.
, 2006, “
Controllable Preparation of Monodisperse O/W and W/O Emulsions in the Same Microfluidic Device
,”
Langmuir
0743-7463,
22
(
19
), pp.
7943
7946
.
19.
Zhao
,
Y. C.
,
Chen
,
G. W.
, and
Yuan
,
Q.
, 2006, “
Liquid-Liquid Two-Phase Flow Patterns in a Rectangular Microchannel
,”
AIChE J.
0001-1541,
52
(
12
), pp.
4052
4060
.
20.
Dessimoz
,
A. L.
,
Cavin
,
L.
,
Renken
,
A.
, and
Kiwi-Minsker
,
L.
, 2008, “
Liquid-Liquid Two-Phase Flow Patterns and Mass Transfer Characteristics in Rectangular Glass Microreactors
,”
Chem. Eng. Sci.
0009-2509,
63
(
16
), pp.
4035
4044
.
21.
Cramer
,
C.
,
Fischer
,
P.
, and
Windhab
,
E. J.
, 2004, “
Drop Formation in a Co-Flowing Ambient Fluid
,”
Chem. Eng. Sci.
0009-2509,
59
(
15
), pp.
3045
3058
.
22.
Buongiorno
,
J.
, 2006, “
Convective Transport in Nanofluids
,”
ASME J. Heat Transfer
0022-1481,
128
(
3
), pp.
240
250
.
23.
Fischer
,
M.
,
Dietzel
,
M.
, and
Poulikakos
,
D.
, 2009, “
Thermally Enhanced Solubility for the Shrinking of a Nanoink Droplet in a Surrounding Liquid
,”
Int. J. Heat Mass Transfer
0017-9310,
52
(
1–2
), pp.
222
231
.
24.
Shin
,
S.
,
Abdel-Khalik
,
S. I.
,
Daru
,
V.
, and
Juric
,
D.
, 2005, “
Accurate Representation of Surface Tension Using the Level Contour Reconstruction Method
,”
J. Comput. Phys.
0021-9991,
203
(
2
), pp.
493
516
.
25.
Hirt
,
C. W.
, and
Nichols
,
B. D.
, 1981, “
Volume of Fluid (VOF) Method for the Dynamics of Free Boundaries
,”
J. Comput. Phys.
0021-9991,
39
(
1
), pp.
201
225
.
26.
Sussman
,
M.
,
Smereka
,
P.
, and
Osher
,
S.
, 1994, “
A Level Set Approach for Computing Solutions to Incompressible 2-Phase Flow
,”
J. Comput. Phys.
0021-9991,
114
(
1
), pp.
146
159
.
27.
Jamet
,
D.
,
Lebaigue
,
O.
,
Coutris
,
N.
, and
Delhaye
,
J. M.
, 2001, “
The Second Gradient Method for the Direct Numerical Simulation of Liquid-Vapor Flows With Phase Change
,”
J. Comput. Phys.
0021-9991,
169
(
2
), pp.
624
651
.
28.
Tryggvason
,
G.
,
Bunner
,
B.
,
Esmaeeli
,
A.
,
Juric
,
D.
,
Al-Rawahi
,
N.
,
Tauber
,
W.
,
Han
,
J.
,
Nas
,
S.
, and
Jan
,
Y. J.
, 2001, “
A Front-Tracking Method for the Computations of Multiphase Flow
,”
J. Comput. Phys.
0021-9991,
169
(
2
), pp.
708
759
.
29.
Gupta
,
A.
, and
Kumar
,
R.
, 2009, “
Effect of Geometry on Droplet Formation in the Squeezing Regime in a Microfluidic T-Junction
,”
Microfluid. Nanofluid.
1613-4982,
8
, pp.
799
812
.
30.
Gupta
,
A.
,
Murshed
,
S. M. S.
, and
Kumar
,
R.
, 2009, “
Droplet Formation and Stability of Flows in a Microfluidic T-Junction
,”
Appl. Phys. Lett.
0003-6951,
94
(
16
), p.
164107
.
31.
Renardy
,
Y.
, and
Renardy
,
M.
, 2002, “
Prost: A Parabolic Reconstruction of Surface Tension for the Volume-of-Fluid Method
,”
J. Comput. Phys.
0021-9991,
183
(
2
), pp.
400
421
.
32.
Brackbill
,
J. U.
,
Kothe
,
D. B.
, and
Zemach
,
C.
, 1992, “
A Continuum Method for Modeling Surface-Tension
,”
J. Comput. Phys.
0021-9991,
100
(
2
), pp.
335
354
.
33.
Graetz
,
L.
, 1883, “
Ueber Die Waermeleitungsfaehigkeit Von Fluessigkeiten (On the Thermal Conductivity of Liquids), Part 1
,”
Ann. Phys. Chem.
0003-3804,
18
, pp.
79
94
.
34.
Eastman
,
J. A.
,
Phillpot
,
S. R.
,
Choi
,
S. U. S.
, and
Keblinski
,
P.
, 2004, “
Thermal Transport in Nanofluids
,”
Annu. Rev. Mater. Res.
1531-7331,
34
(
1
), pp.
219
246
.
35.
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
.
36.
Escher
,
W.
, 2009, private communication.
37.
Shu
,
C. -W.
, and
Osher
,
S.
, 1989, “
Efficient Implementation of Essentially Non-Oscillatory Shock-Capturing Schemes, II
,”
J. Comput. Phys.
0021-9991,
83
(
1
), pp.
32
78
.
38.
Fletcher
,
C. A. J.
, 1991,
Computational Techniques for Fluid Dynamics
,
Springer-Verlag
,
Berlin
.
39.
Shin
,
S.
,
Abdel-Khalik
,
S. I.
, and
Juric
,
D.
, 2005, “
Direct Three-Dimensional Numerical Simulation of Nucleate Boiling Using the Level Contour Reconstruction Method
,”
Int. J. Multiphase Flow
0301-9322,
31
(
10–11
), pp.
1231
1242
.
40.
Lajeunesse
,
E.
, and
Homsy
,
G. M.
, 2003, “
Thermocapillary Migration of Long Bubbles in Polygonal Tubes. II. Experiments
,”
Phys. Fluids
0031-9171,
15
(
2
), pp.
308
314
.
41.
Mohapatra
,
S. C.
and
Loikits
,
D.
, 2005, “
Advances in Liquid Coolant Technologies for Electronics Cooling
,”
21st Annual IEEE Semiconductor Thermal Measurement and Management Symposium
, IEEE, San Jose, CA, pp.
354
360
.
42.
Velagapudi
,
V.
,
Konijeti
,
R. K.
, and
Aduru
,
C. S. K.
, 2008, “
Empirical Correlations to Predict Thermophysical and Heat Transfer Characteristics of Nanofluids
,”
J. Therm. Sci.
1003-2169,
12
(
2
), pp.
27
37
.
43.
Girifalco
,
L. A.
, and
Good
,
R. J.
, 1957, “
A Theory for the Estimation of Surface and Interfacial Energies. 1. Derivation and Application to Interfacial Tension
,”
J. Phys. Chem.
0022-3654,
61
(
7
), pp.
904
909
.
44.
Svitova
,
T.
,
Theodoly
,
O.
,
Christiano
,
S.
,
Hill
,
R. M.
, and
Radke
,
C. J.
, 2002, “
Wetting Behavior of Silicone Oils on Solid Substrates Immersed in Aqueous Electrolyte Solutions
,”
Langmuir
0743-7463,
18
(
18
), pp.
6821
6829
.
45.
Murshed
,
S. M. S.
,
Tan
,
S. H.
, and
Nguyen
,
N. T.
, 2008, “
Temperature Dependence of Interfacial Properties and Viscosity of Nanofluids for Droplet-Based Microfluidics
,”
J. Phys. D: Appl. Phys.
0022-3727,
41
(
8
), pp.
085502
.
46.
Eckert
,
E. R. G.
, and
Drake
,
R. M.
, 1959,
Heat and Mass Transfer, Part A
,
McGraw-Hill
,
New York
.
47.
Deen
,
W. M.
, 1998,
Analysis of Transport Phenomena
,
Oxford University Press
,
Oxford
.
48.
Perry
,
J.
, and
Kandlikar
,
S.
, 2008, “
Fouling and Its Mitigation in Silicon Microchannels Used for IC Chip Cooling
,”
Microfluid. Nanofluid.
1613-4982,
5
(
3
), pp.
357
371
.
You do not currently have access to this content.