Tag Archives: Showme

Research Topics

Gas Diffusion Media

Gas Diffusion Layers (GDLs) are an important component of PEM fuels cells that significantly enhance the mixing and flow homogenization of the reacting species from the flow channels to the catalyst surface of the Membrane Electrode Assembly (MEA). They offer excellent structural strength combined with high electrical and thermal conductivity in the form of a high porosity medium.

GDLs are typical made of unwoven carbon fiber paper produced from Polyacrylonitrile (PAN) filaments with a typical diameter of 8um with a standard paper-making process. The final product is graphitized by heating at temperatures above 2000C and treated with Teflon to increase its hydrophobicity for enhanced water management.

For the microscale study and characterization of GDLs, we perform X-ray micro-ct scans of commercially available carbon paper with a spatial resolution down to 0.66um. The reconstructed skeleton is then used with advanced numerical methods to measure the transport properties of the material, such as species diffusivities, permeabilites and thermal/electrical conductivities. (Related work)

Research Topics

Drying of Porous Materials

Drying in porous media is process involving liquid flow, mass transfer and phase change at liquid-gas interfaces.

We study both theoretically and experimentally how these pore scale phenomena determine the macroscopic behaviour of the process, including recovery rates and phase distribution patterns.

We then propose pore network models that account for all major transport mechanisms identified in our experiments and focus accurate providing predictive results in model and real-life porous media. This research is performed in collaboration with prof. Yanis Yortsos, USC, Dr. A. Stubos, NCSR Demokritos and prof. D. Salin, CNRS. (Related work #1, #2)