Extracting Model Parameters and Paradigms From Neutron Imaging of Dead-Ended Anode Operation

2009 ◽  
Author(s):  
Jason B. Siegel ◽  
Anna G. Stefanopoulou ◽  
Serhat Yesilyurt
Keyword(s):  
Liquid Water ◽  
Front Propagation ◽  
Neutron Imaging ◽  
Model Parameters ◽  
Two Phase ◽  
Pde Model ◽  
Saturation Limit ◽  
Gravity Driven ◽  
Water Accumulation

In a PEMFC, feeding dry hydrogen into a dead-ended anode (DEA), reduces the overall system cost, weight and volume due to reduced need for a hydrogen-grade humidification and recirculation subsystems, but requires purging to remove the accumulated water and inert gas. Although the DEA method of operation might be undesirable due to its associated high spatial variability it provides a unique perspective on the evolution of the water accumulation in the anode. Sections of the channel nearest the inlets are significantly drier than those nearest the outlet as shown in the neutron imaging of a 53 cm2 PEMFC. This method allows in-situ visualization of distinct patterns, including water front propagation along the channels. In this paper we utilize neutron imaging of the liquid water distributions and a previously developed PDE model of liquid water flow in the GDL to (a) identify a range of numerical values for the immobile saturation limit, (b) propose a gravity-driven liquid flow in the channels, and (c) derive the two-phase GDL boundary conditions associated with the presence of liquid water in the channel.

In situ diagnostic of two-phase flow phenomena in polymer electrolyte fuel cells by neutron imaging

2005 ◽  
Vol 50 (13) ◽  
pp. 2603-2614 ◽  
Author(s):  
Denis Kramer ◽  
Jianbo Zhang ◽  
Ryoichi Shimoi ◽  
Eberhard Lehmann ◽  
Alexander Wokaun ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Polymer Electrolyte ◽  
Two Phase Flow ◽  
Polymer Electrolyte Fuel Cells ◽  
Neutron Imaging ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Phenomena

The Experimental Study of Water Accumulation in PEMFC Cathode Channel

2015 ◽  
Author(s):  
Ali Bozorgnezhad ◽  
Mehrzad Shams ◽  
Goodarz Ahmadi ◽  
Homayoon Kanani ◽  
Mohammadreza Hasheminasab
Keyword(s):  
Liquid Water ◽  
Internal Combustion Engines ◽  
Two Phase Flow ◽  
Gas Diffusion ◽  
Green Energy ◽  
Proton Exchange ◽  
Phase Flow ◽  
Two Phase ◽  
Coverage Ratio ◽  
Water Accumulation

In the recent years, Proton Exchange Membrane Fuel Cell (PEMFC) has attracted much attention as a source of green energy and alternative to internal combustion engines. The PEMFC produces electrical power with heat and water as only byproducts. Water is needed to providing proper hydration of membrane and its ionic conductivity in PEMFCs, but excess water accumulation known as flooding phenomenon decreases reaction sites on gas diffusion and increases mass transport loss and consequently it leads to performance loss of PEMFC. Proper water management depends on characterization and study two-phase flow phenomenon of PEMFC as flooding. In the present work, the two-phase flow in the cathode channel of transparent PEMFC with single serpentine flow field is studied by direct optical visualization and utilization of Digital Image Processing for different inlet flow parameters and operational conditions. Liquid water accumulation in the cathode channel is quantified and the water coverage ratio is calculated as a scale of water content of the cathode channel in the unsteady and time-averaged states. Increasing the temperature and stoichiometry decrease the accumulation of liquid water in the cathode channel while increasing the reactants relative humidity leads to accumulation of more liquid water. Observations show in higher cathode stoichiometries, the effect of anode stoichiometry on the water coverage ratio decreases. The effect of anode stoichiometry on the water coverage ratio is more than the cathode stoichiometry. In higher anode stoichiometries, the effect of cathode stoichiometry on the water coverage ratio decreases so that the change in cathode stoichiometry has no significant effect on the values of water coverage ratio.

In Situ Two-Phase Flow Investigation of Proton Exchange Membrane (PEM) Electrolyzer by Simultaneous Optical and Neutron Imaging

2019 ◽  
Vol 41 (1) ◽  
pp. 349-362 ◽  
Author(s):  
Omer F. Selamet ◽  
Ugur Pasaogullari ◽  
Dusan Spernjak ◽  
Daniel S. Hussey ◽  
David L. Jacobson ◽  
...  
Keyword(s):  
Proton Exchange Membrane ◽  
Two Phase Flow ◽  
Proton Exchange ◽  
Neutron Imaging ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Investigation ◽  
Pem Electrolyzer ◽  
Exchange Membrane

Neutron Imaging of Water Accumulation in the Active Area and Channel-to-Manifold Transitions of a PEMFC

2013 ◽  
Author(s):  
Xuan Liu ◽  
Thomas A. Trabold ◽  
Jeffrey J. Gagliardo ◽  
David L. Jacobson ◽  
Daniel S. Hussey
Keyword(s):  
Fuel Cell ◽  
Current Density ◽  
Liquid Water ◽  
Driving Force ◽  
Cell Voltage ◽  
Neutron Imaging ◽  
Active Area ◽  
Water Volume ◽  
Imaging Method ◽  
Water Accumulation

Management of liquid water formed by the electrochemical fuel cell reaction is a key factor in PEMFC performance and durability. For practical stack applications, an important consideration is the transport of liquid water at the transition between the ends of the bipolar plate channels and the manifolds, where excess reactant flows from all the individual cells are combined and directed to the stack exhaust. In this region, gas-phase momentum can be very low, especially on the anode, where there is little driving force to remove liquid water that may accumulate as a result of geometrical or surface energy variations, or due to relatively low temperatures that exist outside of the fuel cell active area. This study seeks to characterize the water accumulated within the active area and at the channel-to-manifold transition regions at both the anode and cathode outlets, as a function of cell operating temperature and current density. The neutron imaging method was applied to directly measure the water volumes within the transition regions, and provide a comparison to simultaneously measured water volume within the cell active area. Transition-region water was found to be weakly dependent on current density, suggesting that once water forms in this area, little driving force exists to extract it entirely by means of gas momentum. Moreover, it was found that the active area water volume is strongly dependent on cell temperature, and temperature variation of as little as 0.5 °C can produce a significant change in water accumulation which is reflected in the cell voltage.

In situ diagnostic of two-phase flow phenomena in polymer electrolyte fuel cells by neutron imaging

2006 ◽  
Vol 51 (13) ◽  
pp. 2715-2727 ◽  
Author(s):  
Jianbo Zhang ◽  
Denis Kramer ◽  
Ryoichi Shimoi ◽  
Yoshitaka Ono ◽  
Eberhard Lehmann ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Polymer Electrolyte ◽  
Two Phase Flow ◽  
Polymer Electrolyte Fuel Cells ◽  
Neutron Imaging ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Phenomena

Effect of PEFC Rib/Channel Width on Liquid Water Accumulation and Discharge by In-situ X-Ray Imaging

2019 ◽  
Vol 92 (8) ◽  
pp. 147-152
Author(s):  
Takahiro Komiyama ◽  
Takashi Sasabe ◽  
Katsuyuki Kawamura ◽  
Hiroshi Naito ◽  
Shuichiro Hirai
Keyword(s):  
Liquid Water ◽  
Channel Width ◽  
X Ray ◽  
X Ray Imaging ◽  
Water Accumulation
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