Abstract
The study of water and gas transport through fibrous gas diffusion layer (GDL) is important to the optimization of proton exchange membrane fuel cells (PEMFCs). In this work, analytical models of dimensionless permeability, and water and gas relative permeabilities of fibrous GDL in PEMFCs are derived using fractal theory. In our models, the structure of fibrous GDL is characterized in terms of porosity, tortuosity fractal dimension (DT), pore area fractal dimensions (df), water phase (df,w) and gas phase (df,g) fractal dimensions. The predicted dimensionless permeability, water and gas relative permeabilities based on the proposed models are in good agreement with experimental data and predictions of numerical simulations reported in the literature. The model reveals that, although water phase and gas phase fractal dimensions strongly depend on porosity, the water and gas relative permeabilities are independent of porosity and are a function of water saturation only. It is also shown that the dimensionless permeability decreases significantly with the increase of tortuosity fractal dimension. On the other hand, there is only a small decrease in the water and gas relative permeabilities when tortuosity fractal dimension increases. One advantage of the proposed analytical model is that it contains no empirical constant, which is normally required in past models. © 2014 Elsevier Ltd.
Original language | English |
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Pages (from-to) | 222-231 |
Number of pages | 10 |
Journal | Electrochimica Acta |
Volume | 134 |
DOIs | |
Publication status | Published - 10 Jul 2014 |
Keywords
- Fractal analytical model
- Gas diffusion layer
- Permeability
- Proton exchange membrane fuel cell
- Relative permeability
ASJC Scopus subject areas
- General Chemical Engineering
- Electrochemistry