Numerical quantification of water saturation, back diffusion, electro-osmotic drag and water generation in polymer electrolyte membrane fuel cells
Author
Summary, in English
A 3D unit cell has been simulated numerically using a commercial software
in order to evaluate and quantify various water related phenomena,
i.e., electro-osmotic drag, back diffusion, electro-chemical water generation
and the saturation effects in the porous media. The water saturation
effects were noticed to be more pronounced in the GDL of the cathode
as compared to the catalyst layer due to greater pore dimensions. Also,
a comparison of the water saturation effects were studied at different operating
voltages of 0.7, 0.5 and 0.3 V. In case of 0.7 and 0.5 V, it was
seen that the saturation effects were found to be located in the far region
of the inlet because of the decreasing ability of air to accommodate more
water. But, at the lower voltage of 0.3, the saturation effects started to
appear in the inlet region too due to strong electro-osmotic drag and water
generation due to electro-chemical reactions. The transfer of water from
the cathode via back diffusion also increased accordingly by lowering the
operating voltage. Additionally, the transfer rate of water due to the back
diffusion was observed to be larger than the water addition due to both
the electro-osmotic drag and the electro-chemical generation.
in order to evaluate and quantify various water related phenomena,
i.e., electro-osmotic drag, back diffusion, electro-chemical water generation
and the saturation effects in the porous media. The water saturation
effects were noticed to be more pronounced in the GDL of the cathode
as compared to the catalyst layer due to greater pore dimensions. Also,
a comparison of the water saturation effects were studied at different operating
voltages of 0.7, 0.5 and 0.3 V. In case of 0.7 and 0.5 V, it was
seen that the saturation effects were found to be located in the far region
of the inlet because of the decreasing ability of air to accommodate more
water. But, at the lower voltage of 0.3, the saturation effects started to
appear in the inlet region too due to strong electro-osmotic drag and water
generation due to electro-chemical reactions. The transfer of water from
the cathode via back diffusion also increased accordingly by lowering the
operating voltage. Additionally, the transfer rate of water due to the back
diffusion was observed to be larger than the water addition due to both
the electro-osmotic drag and the electro-chemical generation.
Department/s
Publishing year
2011
Language
English
Publication/Series
Journal of Power Sources
Document type
Journal article
Publisher
Elsevier
Topic
- Energy Engineering
Status
Submitted
ISBN/ISSN/Other
- ISSN: 1873-2755