کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
7057734 1458071 2014 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Oxygen transport resistance correlated to liquid water saturation in the gas diffusion layer of PEM fuel cells
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی جریان سیال و فرایندهای انتقال
پیش نمایش صفحه اول مقاله
Oxygen transport resistance correlated to liquid water saturation in the gas diffusion layer of PEM fuel cells
چکیده انگلیسی
Under typical proton exchange membrane fuel cell (PEMFC) operating conditions, temperature gradients through the porous gas diffusion layer (GDL) can result in product water condensation. As a result, non-uniform partial saturation of the GDL changes the local effective porosity and tortuosity encountered by oxygen diffusing to the catalyst layer. This additional transport resistance reduces the partial pressure of oxygen at the catalyst surface of an air-fed cathode. In the current work, this phenomenon is investigated in two-dimensions using limiting current experiments that define GDL boundary conditions along with simultaneous neutron imaging to measure the local water content relative to the flow field geometry. The subsequent effective diffusion coefficient vs. saturation relationship derived from this method is reported for two common GDL carbon fiber substrates. It is also shown that the land vs. channel distribution of liquid water must be accounted for to accurately predict diffusion resistance. These results represent the first time that the effect of water saturation on effective diffusion coefficient has been directly measured in situ, thus enabling accurate determination of the exponent “n” in the modified Bruggeman relationship for two commercially available gas diffusion layer materials.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Heat and Mass Transfer - Volume 71, April 2014, Pages 585-592
نویسندگان
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