Non-isothermal two-phase transport in a polymer electrolyte membrane fuel cell with crack-free microporous layers
Autor: | Yuichiro Tabuchi, Hang Liu, Mohammadreza Fazeli, Nan Ge, Stéphane Chevalier, Aimy Bazylak, Patrick Antonacci, Jongmin Lee, Michael G. George, Toshikazu Kotaka, Ronnie Yip, ChungHyuk Lee, Rupak K. Banerjee |
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Rok vydání: | 2017 |
Předmět: |
Fluid Flow and Transfer Processes
Materials science Capillary action 020209 energy Mechanical Engineering 02 engineering and technology Electrolyte Microporous material 021001 nanoscience & nanotechnology Condensed Matter Physics Cathode Isothermal process law.invention Temperature gradient Chemical engineering law Phase (matter) 0202 electrical engineering electronic engineering information engineering 0210 nano-technology Water vapor |
Zdroj: | International Journal of Heat and Mass Transfer. 107:418-431 |
ISSN: | 0017-9310 |
Popis: | Liquid water breakthrough events were observed in crack-free microporous layers (MPLs) of operating polymer electrolyte membrane (PEM) fuel cells through in situ synchrotron X-ray radiography. The measured water thicknesses were used as inputs into a one-dimensional (1D) heat and mass transport model. This 1D model was developed to describe the coupled relationship between liquid and vapour transport through the cathode GDL and the temperature distributions in the fuel cell that accompany the in operando measurements. The current density was increased from 1.4 to 2.4 A cm −2 , during which MPL breakthrough was observed. Immediately following MPL breakthrough events, the fraction of vapour-phase transport of the total water flux in the MPL increased by up to 5%. Post MPL breakthrough, further increases in current density resulted in increased thermal and water vapour concentration gradients in the MPL, and vapour transport was further enhanced. A temperature gradient at the cathode catalyst layer (CL)–MPL interface resulted in decreased threshold capillary pressures, and as a result higher liquid water saturations were observed near this interface. These findings suggest that the temperature gradient should be considered in two-phase flow modeling and pore network modeling due to its impact on liquid water distributions. |
Databáze: | OpenAIRE |
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