Photothermal deflection measurement of effective gas diffusion
coefficient of a porous medium |
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Authors: | J H Rohling J Shen C Wang J Zhou C E Gu |
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Institution: | (1) National Research Council of Canada, Institute for Fuel Cell Innovation, 4250 Wesbrook Mall, Vancouver, British Columbia, V6T 1W5, Canada;(2) Institute of Modern Optical Technologies, Suzhou University, Suzhou, Jiangsu, 215006, P.R. China |
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Abstract: | In this work, an effective gas diffusion coefficient of a
porous medium was measured using photothermal deflection (PD) technique. An
in-house made Loschmidt diffusion cell with a photothermal-deflection probe
were employed to measure the effective gas diffusion coefficient of a gas
diffusion layer (GDL) with a porosity ε ≈ 0.7. The concentration
evolutions of CO2 in O2 with and without the GDL were measured,
respectively, using a transverse normal PD technique. The concentration
variations were used to deduce the gas diffusion coefficients in the
presence and absence of the GDL by solving mass diffusion equations. The
effective gas diffusion coefficient of the GDL was calculated from the
diffusion coefficients using a model of an equivalent resistance to
diffusion and found to be 4.39 × 10-6 m2s-1,
demonstrating that PD technique can be employed to determine the effective
gas diffusion coefficient of a porous medium. |
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Keywords: | |
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