Biomedical Engineering Reference
In-Depth Information
a
d
b
e
Re = 1
Re = 10
c
Re = 50
100 µm
FIGURE 3.97
A.passive.micromixer.that.induces.luid.rotation..(From.Sung-Jin.Park,.Jung.Kyung.
Kim,.Junha.Park,.Seok.Chung,.Chani.Chung,.and.Jun.Keun.Chang,.“Rapid.three-dimensional.pas-
sive. rotation. micromixer. using. the. breakup. process,”.
J. Micromech. Microeng.
. 14,. 6-14,. 2004..
Reproduced.with.permission.from.the.Institute.of.Physics..Figure.contributed.by.Jun.Keun.Chang.)
The first interface of two
injected fluids formed at
the T-junction
The first
recombination region
Solute
concentration
a
b
Outlet flow
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
Recombination region
Inlet flow
250 µm
6 mm
“F”-shape mixing unit
Splitting region
Re = 3.89
Inlet flow
c
Solute
concentration
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
250 µm
A
B
C
D
E
F
G
Interface of two
injected fluids
H
I
J
K
6 mm
FIGURE 3.98
Microluidic.homogenizer.with.3-D.“F”.splitter-recombiners..(From.Dong.Sung.Kim,.
Se.Hwan.Lee,.Tai.Hun.Kwon,.and.Chong.H..Ahn,.“A.serpentine.laminating.micromixer.combining.
splitting/recombination.and.advection,”.
Lab Chip
.5,.739-747,.2005..Reproduced.with.permission.
from.The.Royal.Society.of.Chemistry.)
mixing length is approximately 5 to 7 mm within the range of Re = 0-12; therefore, mixing in
this design is very insensitive to Re at low Re, although it works better for faster low rates.
Of course, splitting and recombining can also be achieved with crisscrossing 3-D microchan-
nel architectures, but the drawback is that these can only be manufactured with two-photon absorp-
tion stereolithography. Dong-Pyo Kim's group from KAIST the Korea Advanced Institute of
Science and Technology (in Daejeon, South Korea) has used this “brute force” approach to man-
ufacture highly eicient mixers in SU-8. At Re = 1 and Pe = 1000, complete mixing of water and
ethanol is achieved in just 250 μm (
Figure 3.99
).
