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Thèse Benjamin Straubhaar

27 octobre 2015

Numerical simulations on pore networks. Application to water formation and growth by condensation in the gas diffusion layers (GDL) of PEM fuel cells.

Thèse Benjamin Straubhaar

Lundi 30 novembre à 14 h 00 - Amphithéâtre Nougaro

Sous réserve d’autorisation de soutenance par les rapporteurs

Abstract :

A Proton Exchange Membrane Fuel Cell (PEMFC) is a device converting hydrogen into electricity thanks to an electrochemical reaction called reverse electrolysis. Like every fuel cell or battery, PEMFCs are made of a series of layers. We are interested in the gas diffusion layer (GDL) on the cathode side. The GDL is made of carbon fibers treated hydrophobic. It can be seen as a thin porous medium with a mean pore size of few tens of microns.

A key question in this system is the management of the water produced by the reaction. In this context, the main objective of the thesis is the development of a numerical tool aiming at simulating the liquid water formation within the GDL. A pore network approach is used. We concentrate on a scenario where liquid water forms in the GDL by condensation. Comparisons between simulations and experiments performed with a two-dimensional microfluidic device are first presented for different wettability conditions, temperature distributions and inlet relative humidity in order to validate the model.

A sensitivity study is then performed to better characterize the parameters controlling the water invasion.

Finally, simulations are compared with in situ experimental water distributions obtained by X-ray micro-tomography as well as with experimental distributions from the literature obtained by neutron imaging.

Key words : Fuel cell, Gas diffusion layer, Porous medium, Pore network model, condensation

Felix BÜCHI - (Group Head, Fuel Cell Systems and Diagnostics, Paul Scherrer Institute) - Rapporteur

Gaël MARANZANA (Professeur, LEMTA) - Rapporteur

Yann BULTEL (Professeur, LEPMI) - Président du jury

Christophe TURPIN (Chargé de Recherche HDR CNRS, LAPLACE) - Examinateur

Marc PRAT (Directeur de Recherche CNRS, IMFT) - Directeur de thèse

Joël PAUCHET (Ingénieur de recherche, CEA) - Membre invité