## Free convective Row for laminar, two-dimensional divergent channels with isothermal boundary conditions has been numerically analyzed. The study examines the effect of semi-vertical angles on the fluid flow and heat transfer rates for a Rayleigh number range of 10 to 4 x 10' considering water
Investigation of Channel-to-Channel Cross Convection in Serpentine Flow Fields
✍ Scribed by D. Tehlar; R. Flückiger; A. Wokaun; F. N. Büchi
- Publisher
- John Wiley and Sons
- Year
- 2010
- Tongue
- English
- Weight
- 934 KB
- Volume
- 10
- Category
- Article
- ISSN
- 1615-6846
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✦ Synopsis
Channel-to-channel cross convection in serpentine flow fields of polymer electrolyte fuel cells (PEFC) can influence the overall cell performance. The effect strongly depends on the gas transport properties of the gas diffusion layer (GDL). For the first time measured anisotropic, compression dependent permeability and effective diffusivity of GDLs are used to quantify the influence of cross convection on the local current distribution and performance. A model was developed to examine different channel-rib geometries and GDL characteristics. The results show that cross convection can significantly increase the current density and consequently the power density of PEFCs. A strong sensitivity to GDL compression, flow velocity and rib width was found. As an optimised case the GDL thickness under the rib was increased resulting in about 20% higher current densities. Precise knowledge of the GDL characteristics and its compression are key to understand channel-to-channel cross convection and optimise perfomance.
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A serpentine flow channel can be considered as neighboring channels connected in series, and is one of the most common and practical channel layouts for polymer electrolyte membrane (PEM) fuel cells, as it ensures the removal of liquid water produced in a cell with good performance and acceptable pa
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