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
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