Forchheimer's inertial effect on liquid water removal in proton exchange membrane fuel cells with baffled flow channels

The most critical aspect of fuel cell water management is the delicate balance of membrane hydration and avoiding cathode flooding. Liquid water accumulation in the interfacial contact area between the flow channel landing and gas diffusion layer (GDL) can dramatically impact steady and transient performance of proton exchange membrane fuel cells (PEMFCs). In this concern, a porous landing could facilitate water removal in the cathode flow channel and significantly improve PEMFCs performance. In this work, an attempt has been made to fabricate the porous interdigitated cathode flow channels from a porous carbon sheet. Performance measurements have been made with nominally identical PEMFCs using non-porous (serpentine and interdigitated) and porous (interdigitated) cathode flow channels. PEMFCs with porous interdigitated flow channels had 48% greater power output than PEMFCs with non-porous interdigitated flow channels at high current densities. For the non-porous interdigitated flow channel, significant performance loss appears to arise from greatly reduced oxygen transport rates when the water generation rate exceeds the water removal rate, however for the porous interdigitated flow channel, the design removes the accumulated liquid water from the landing area through the capillarity of its porous structure and eliminates the stagnant regions under the landing, thereby reducing liquid flooding in the interface between landing and GDL area.

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Diagnostic tool to detect liquid water removal in the cathode channels of proton exchange membrane fuel cells

Journal of Power Sources ◽

10.1016/j.jpowsour.2006.06.055 ◽

2006 ◽

Vol 162 (1) ◽

pp. 469-473 ◽

Cited By ~ 40

Author(s):

H.P. Ma ◽

H.M. Zhang ◽

J. Hu ◽

Y.H. Cai ◽

B.L. Yi

Keyword(s):

Fuel Cells ◽

Liquid Water ◽

Diagnostic Tool ◽

Proton Exchange Membrane ◽

Proton Exchange ◽

Water Removal ◽

Exchange Membrane

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The Effect of Nonuniform Under-Rib Convection on Reactant and Liquid Water Distribution in Proton Exchange Membrane Fuel Cells

Journal of Fuel Cell Science and Technology ◽

10.1115/1.4030514 ◽

2015 ◽

Vol 12 (4) ◽

Cited By ~ 1

Author(s):

P. K. Jithesh ◽

T. Sundararajan ◽

Sarit K. Das

Keyword(s):

Fuel Cells ◽

Liquid Water ◽

Water Distribution ◽

Proton Exchange Membrane ◽

Proton Exchange ◽

Water Removal ◽

Mixed Flow ◽

Exchange Membrane ◽

Flow Distributor ◽

Reactant Distribution

The performance of a proton exchange membrane (PEM) fuel cell strongly depends on the nature of reactant distribution and the effectiveness of liquid water removal. In this work, three different configurations of a mixed flow distributor are studied analytically and numerically to find out the effect of nonuniform under-rib convection on reactant and liquid water distribution in the cell. In a mixed flow distributor, the rate of under-rib convection is found to be different under each rib in the same flow sector which results in different rates of removal of liquid water. This helps to retain some water to hydrate the membrane, whereas the excess is removed to avoid flooding. It is found that under-rib convection aids to get better reactant distribution, reduces pressure drop, and provides better control over liquid water removal which is helpful in developing efficient water management strategies for PEM fuel cells.

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