This paper describes an approximate method for analyzing two-phase flow of gas and liquid water in fuel cell channels, whose surfaces are sufficiently hydrophilic for liquid water to wick spontaneously into the channel corners. This analysis is used to address the important question of whether the gas flow at typical stoichiometries in such channels is sufficient to remove all the liquid water generated in a proton exchange membrane fuel cell. Since fuel channels are usually much narrower than they are long, it is possible to adopt the usual approximations of lubrication theory and to decompose the general solution for the liquid motion into two parts: (1) that driven by the channel pressure gradient and (2) that driven by surface shear stress from the faster moving gas. When both parts of the solution are combined with the mass balance equations, it is possible to derive a pair of partial differential equations for the water depth and gas flow rate that depend on distance down the channel and time. Steady solutions of these equations are explored to determine the amount of liquid water that accumulates in the channel over a broad range of fuel cell operating conditions.

1.
Tuber
,
K.
,
Pocza
,
D.
, and
Hebling
,
C.
, 2003, “
Visualization of Water Buildup in the Cathode of a Transparent PEM Fuel Cell
,”
J. Power Sources
0378-7753,
124
, pp.
403
414
.
2.
Hakenjos
,
A.
,
Muenter
,
H.
,
Wittstadt
,
U.
, and
Hebling
,
C.
, 2004, “
A PEM Fuel Cell for Combined Measurement of Current and Temperature Distribution, and Flow Field Flooding
,”
J. Power Sources
0378-7753,
131
, pp.
213
216
.
3.
Yang
,
X. G.
,
Zhang
,
F. Y.
,
Lubawy
,
A. L.
, and
Wang
,
C. Y.
, 2004, “
Visualization of Liquid Water Transport in a PEFC
,”
Electrochem. Solid-State Lett.
1099-0062,
7
, pp.
A408
A411
.
4.
Zhang
,
F. Y.
,
Yang
,
X. G.
, and
Wang
,
C. Y.
, 2006, “
Liquid Water Removal From a Polymer Electrolyte Fuel Cell
,”
J. Electrochem. Soc.
0013-4651,
153
, pp.
A225
A232
.
5.
Bellows
,
R. J.
,
Lin
,
M. Y.
,
Arif
,
M.
,
Thompson
,
A. K.
, and
Jacobson
,
D.
, 1999, “
Neutron Imaging Technique for In Situ Measurement of Water Transport Gradients Within Nafion in Polymer Electrolyte Fuel Cells
,”
J. Electrochem. Soc.
0013-4651,
146
, pp.
1099
1103
.
6.
Geiger
,
A. B.
,
Tsukada
,
A.
,
Lehmann
,
E.
,
Vontobel
,
P.
,
Wokaun
,
A.
, and
Scherer
,
G. G.
, 2002, “
In Situ Investigation of Two-Phase Flow Patterns in Flow Fields of PEFC’s Using Neutron Radiography
,”
Fuel Cells
0532-7822,
2
, pp.
92
98
.
7.
Chuang
,
P. A.
,
Turhan
,
A.
,
Heller
,
A. K.
,
Brenizer
,
J. S.
,
Trabold
,
T. A.
, and
Mench
,
M. M.
, 2005, “
The Nature of Flooding and Drying in Polymer Electrolyte Fuel Cells
,”
Proceedings of the Third International Conference on Fuel Cell Science, Engineering and Technology
, Ypsilanti, MI.
8.
Satija
,
R.
,
Jacobson
,
D. L.
,
Arif
,
M.
, and
Werner
,
S. A.
, 2004, “
In Situ Neutron Imaging Technique for Evaluation of Water Management Systems in Operating PEM Fuel Cells
,”
J. Power Sources
0378-7753,
129
, pp.
238
245
.
9.
Meng
,
H.
, and
Wang
,
C.
, 2005, “
Model of Two-Phase Flow and Flooding Dynamics in Polymer Electrolyte Fuel Cells
,”
J. Electrochem. Soc.
0013-4651,
152
, pp.
A1733
A1741
.
10.
Quan
,
P.
,
Zhou
,
B.
,
Sobiesiak
,
A.
, and
Liu
,
Z.
, 2005, “
Water Behavior in Serpentine Micro-Channel for Proton Exchange Membrane Fuel Cell Cathode
,”
J. Power Sources
0378-7753,
152
, pp.
131
145
.
11.
Jiao
,
K.
,
Zhou
,
B.
, and
Quan
,
P.
, 2006, “
Liquid Water Transport in Parallel Serpentine Channels With Manifolds on Cathode Side of a PEM Fuel Cell Stack
,”
J. Power Sources
0378-7753,
154
, pp.
124
137
.
12.
Jiao
,
K.
,
Zhou
,
B.
, and
Quan
,
P.
, 2006, “
Liquid Water Transport in Straight Micro-Parallel-Channels With Manifolds for PEM Fuel Cell Cathode
,”
J. Power Sources
0378-7753,
157
, pp.
226
243
.
13.
Zhan
,
Z.
,
Xiao
,
J.
,
Pan
,
M.
, and
Yuan
,
R.
, 2006, “
Characteristics of Droplet and Film Water Motion in the Flow Channels of Polymer Electrolyte Membrane Fuel Cells
,”
J. Power Sources
0378-7753,
160
, pp.
1
9
.
14.
Cai
,
Y. H.
,
Hu
,
J.
,
Ma
,
H. P.
,
Yi
,
B. L.
, and
Zhang
,
H. M.
, 2006, “
Effects of Hydrophilic/Hydrophobic Properties on the Water Behavior in Micro-Channels of a Proton Exchange Membrane Fuel Cell
,”
J. Power Sources
0378-7753,
161
, pp.
843
848
.
15.
Ransohoff
,
T. C.
, and
Radke
,
C. J.
, 1988, “
Laminar Flow of Wetting Liquid Along Corners of a Predominantly Gas-Occupied Noncircular Pore
,”
J. Colloid Sci.
0095-8522,
121
, pp.
392
401
.
16.
Weislogel
,
M. M.
, and
Lichter
,
S.
, 1998, “
Capillary Flow in an Interior Corner
,”
J. Fluid Mech.
0022-1120,
373
, pp.
349
378
.
17.
Concus
,
P.
, and
Finn
,
R.
, 1969, “
On the Behavior of a Capillary Surface in a Wedge
,”
Appl. Math. Sci.
0066-5452,
63
, pp.
292
299
.
18.
Schlichting
,
H.
, 1968,
Boundary Layer Theory
,
6th ed.
,
McGraw-Hill
,
New York
, pp.
108
114
.
19.
Chandraskhar
,
S.
, 1961,
Hydrodynamic and Hydromagnetic Stability
,
Oxford University Press
,
London
, pp.
481
512
.
20.
Su
,
S. K.
, and
Lai
,
C. L.
, 2004, “
Interfacial Shear-Stress Effects on Transient Capillary Wedge Flow
,”
Phys. Fluids
1070-6631,
16
, pp.
2033
2043
.
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