Liquid Water Storage, Distribution, and Removal from Diffusion Media in PEFCS

2006 ◽  
Vol 153 (10) ◽  
pp. A1971 ◽  
Author(s):  
J. J. Kowal ◽  
A. Turhan ◽  
K. Heller ◽  
J. Brenizer ◽  
M. M. Mench
Keyword(s):  
Liquid Water ◽  
Water Storage ◽  
Diffusion Media ◽  
Storage Distribution

Predicting Liquid Water Saturation Through Differently Structured Cathode Gas Diffusion Media of a Proton Exchange Membrane Fuel Cell

2012 ◽  
Vol 9 (2) ◽  
Author(s):  
N. Akhtar ◽  
P. J. A. M. Kerkhof
Keyword(s):  
Fuel Cell ◽  
Liquid Water ◽  
Proton Exchange Membrane ◽  
Water Saturation ◽  
Catalyst Layer ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Diffusion Media ◽  
Exchange Membrane

The role of gas diffusion media with differently structured properties have been examined with emphasis on the liquid water saturation within the cathode of a proton exchange membrane fuel cell (PEMFC). The cathode electrode consists of a gas diffusion layer (GDL), a micro-porous layer and a catalyst layer (CL). The liquid water saturation profiles have been calculated for varying structural and physical properties, i.e., porosity, permeability, thickness and contact angle for each of these layers. It has been observed that each layer has its own role in determining the liquid water saturation within the CL. Among all the layers, the GDL is the most influential layer that governs the transport phenomena within the PEMFC cathode. Besides, the thickness of the CL also affects the liquid water saturation and it should be carefully controlled.

Importance of ice layers on liquid water storage within a snowpack

1999 ◽  
Vol 13 (12-13) ◽  
pp. 1799-1805 ◽  
Author(s):  
Pratap Singh ◽  
Gerhard Spitzbart ◽  
H. Huebl ◽  
H. W. Weinmeister
Keyword(s):  
Liquid Water ◽  
Water Storage

Effect of the Micro-Porous Layer-Gas Diffusion Layer Interface on Water Transport in Polymer Electrolyte Fuel Cells

2009 ◽  
Author(s):  
Joshua Preston ◽  
Richard Fu ◽  
Xiaoyu Zhang ◽  
Ugur Pasaogullari
Keyword(s):  
Polymer Electrolyte ◽  
Cross Section ◽  
Porous Layer ◽  
Diffusion Layer ◽  
Liquid Water ◽  
Water Saturation ◽  
Numerical Models ◽  
Gas Diffusion Layer ◽  
Gas Diffusion ◽  
Diffusion Media

An investigation of the liquid water saturation across the cross-section of an operating polymer electrolyte fuel cell is performed to analyze the saturation discontinuity predicted by numerical models. Numerical models have predicted a discontinuity in the liquid water saturation at the interface of the micro-porous layer and the coarser macroporous region of the gas diffusion layer. High-resolution through plane neutron radiography is used to acquire the water content distribution across the thickness of the gas-diffusion layer and study the effects of the interface. The measured liquid water profiles indicate no obvious discontinuity in the liquid water saturation across the cross-section of the bi-layer gas diffusion layer when large areas are averaged spatially. Evidence of the discontinuity is found when small spatial averaging is used in certain locations. Other locations show no evidence of the discontinuity. Scanning electron microscopy is used to examine the microstructure of two types of the bi-layer diffusion media. The images show that the approximation of the interface as a sudden, distinct feature may not be appropriate. The results suggest that a model that considers the existence of an interfacial region in the diffusion media may be appropriate, in which the properties vary continuously.

Passive control of liquid water storage and distribution in a PEFC through flow-field design

2008 ◽  
Vol 180 (2) ◽  
pp. 773-783 ◽  
Author(s):  
A. Turhan ◽  
K. Heller ◽  
J.S. Brenizer ◽  
M.M. Mench
Keyword(s):  
Flow Field ◽  
Liquid Water ◽  
Passive Control ◽  
Water Storage ◽  
Through Flow ◽  
Flow Field Design

scholarly journals Liquid water storage in snow and ice in 86 Eastern Alpine basins and its changes from 1970–97 to 1998–2006

2016 ◽  
Vol 57 (72) ◽  
pp. 11-18 ◽  
Author(s):  
Michael Kuhn ◽  
Kay Helfricht ◽  
Martin Ortner ◽  
Johannes Landmann ◽  
Wolfgang Gurgiser
Keyword(s):  
Water Balance ◽  
Liquid Water ◽  
Water Retention ◽  
Water Storage ◽  
Distributed Model ◽  
Study Region ◽  
Ice Melt ◽  
Snow And Ice

ABSTRACTThe retention and release of liquid water in glacierized basins was modelled with a conceptual, semi-distributed model of the water and ice balance designed for long-term averages with monthly resolution for 100 m elevation bands. Here we present the components of the liquid water balance of 86 mostly glacierized basins on either side of the main Alpine divide between 10 and 13°E in the period 1998–2006 and compare them with the records of 30 basins monitored from 1970 to 1997. Basin average of liquid water retention has maxima in excess of 100 mm per month in May, often followed by maximum release when the retaining snow matrix melts. Glacier storage peaks in August partly due to ice melt and the ensuing filling of the englacial reservoirs and partly on account of a precipitation maximum. These two components combined to a common maximum of storage in summer in the first period 1970–97 and developed two distinct maxima in the warmer period 1998–2006. A further maximum of liquid water storage that was often found in October is most likely due to a peak in precipitation in the southern part of the study region.

Liquid Water Transport in Polymer Electrolyte Fuel Cells With Multi-Layer Diffusion Media

2004 ◽  
Author(s):  
Ugur Pasaogullari ◽  
Chao-Yang Wang ◽  
Ken S. Chen
Keyword(s):  
Pore Size ◽  
Polymer Electrolyte ◽  
Liquid Water ◽  
Average Pore Size ◽  
Gas Diffusion ◽  
Polymer Electrolyte Fuel Cells ◽  
Two Phase ◽  
Average Pore ◽  
Diffusion Media ◽  
Liquid Water Transport

A two-phase, multi-component, full cell model is developed in order to analyze the two-phase transport in polymer electrolyte fuel cells with multi-layer cathode gas diffusion media, consisting of a coarse gas diffusion layer (GDL) (average pore size ~ 10 μm) and a micro-porous layer (MPL) (average pore size ~ 0.2–2 μm). The relevant structural properties of MPL, including average pore size, wettability, thickness and porosity are examined and their effects on liquid water transport are discussed. It is found that MPL promotes back-flow of liquid water across the membrane towards the anode, consequently alleviating cathode flooding. Furthermore, it is seen that unique porous and wetting characteristics of MPL causes a discontinuity in the liquid saturation at MPL-GDL interface, which in turn reduces the amount of liquid water in cathode catalyst layer-gas diffusion medium interface in some cases. Our analyses show that the back-flow of liquid water increases with the increasing thickness and decreasing pore size, hydrophobicity and bulk porosity of the MPL.

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