|Title:||Numerical simulation of liquid water saturation in cathode side gas diffusion layers of PEFCs|
|Authors :||Dujc, Jaka|
|Conference details:||12th Symposium on Fuel Cell and Battery Modeling and Experimental Validation – ModVal 12, Freiburg, Germany, 26 - 27 March 2015|
|License (according to publishing contract) :||Licence according to publishing contract|
|Type of review:||Not specified|
|Subjects :||Fuel cell; PEM; Simulation|
|Subject (DDC) :||621.3: Electrical engineering and electronics|
|Abstract:||The research and the development of PEMFC systems is an ongoing process with an increasing demand for accurate numerical models. One of the main challenges that require further investigation is related to the two phase (liquid and gas) water transport in the porous media of the polymer electrolyte membrane fuel cells. Here, we focus on the 2D simulation of the cathode’s gas diffusion layer. The model consists of several coupled components: the mechanical part, the two phase flow, the transport of gas species and the electrochemical part. The role of the mechanical part is to capture the compression of the membrane electrode assembly during the fuel cell construction. The effective porosity of the GDL is related to the volumetric strain, a compression measure obtained by the mechanical model (see Fig. 1). The two phase flow is based on the Van Genuchten model (see e.g. ). The transport of species part considers the diffusion and the convection of the oxygen and the water vapor. The volumetric rate of the interfacial mass transfer between the liquid phase and the water vapor phase is modelled by using the Hertz-Knudsen-Langmuir condensation equation (see ). The electrochemical part is modelled as a boundary interface between the GDL and the catalyst layer. Here, the oxygen is consumed and the water vapor is produced. The rates of production are dependent on the local current density. We present a numerical model built by using COMSOL Multiphysics (see ). The effective porosity of the compressed GDL is presented (see Fig. 1) as well as the distributions of the oxygen and the water vapor concentrations. The results obtained by the numerical model are compared with the results obtained by neutron radiography imaging. Both the neutron radiography and the numerical model show the accumulation of liquid water under the ribs. Experimental data and simulation results are in good agreement.|
|Departement:||School of Engineering|
|Publication type:||Conference Poster|
|Appears in Collections:||Publikationen School of Engineering|
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