Search for dissertations about: "Fuel cells porosity"

Showing result 1 - 5 of 13 swedish dissertations containing the words Fuel cells porosity.

2. 1. On Microstructural Analysis of Porous Media Existing in Fuel Cells Using the Lattice Boltzmann Method

   Author : Mayken Espinoza Andaluz; Värmeöverföring; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Porous media; lattice Boltzmann method; microscale; Gas-phase tortuosity; Porosity; Fuel Cell;

   Abstract : This Licentiate thesis aims to gain understanding related to the fluid behavior in porous media existent in fuel cells (FCs) at microscale. In order to achieve this; the widely used methodology for solving problems in porous media has been applied, the Lattice Boltzmann Method (LBM). READ MORE

4. 2. Analysis of Deformation of Gas Diffusion Layers and the Impact on Performance of PEM Fuel Cells

   Author : Jiatang Wang; Värmeöverföring; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; PEM fuel cell; compression ratio; assembly pressure; porosity; deformed GDL; electric resistance; transport phenomena; model; performance; analysis; OpenFOAM;

   Abstract : Proton exchange membrane (PEM) fuel cells have been promoted due to significant breakthroughs in various aspects and increasing public interests. The porous features of the gas diffusion layer (GDL) and the necessary assembly processes generate localized pressure forces on the channel/shoulder structure of the bi-polar plates (BPP). READ MORE

5. 3. On Diffusion Transport Properties in Fuel Cell Gas Diffusion Layers Using the Lattice Boltzmann Method

   Author : Mayken Espinoza Andaluz; Värmeöverföring; []
   Keywords : PEFC; lattice Boltzmann method; gas diffusion layers; porosity; Gas-phase tortuosity; permeability; inertial coefficient; diffusibility; pore-scale modeling;

   Abstract : The polymer electrolyte fuel cell (PEFC) is considered as one of the most promising devices for providing efficient, clean and noiseless conversion of chemical energy to electrical energy. This device can provide electrical and thermal energy for transport, mobile and stationary applications ranging in a wide range of power requirements. READ MORE

6. 4. Electrode degradation in proton exchange membrane fuel cells

   Author : Alejandro Oyarce; Göran Lindbergh; Carina Lagergren; Steven Holdcroft; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; PEMFC; PEFC; Porous electrodes; Carbon corrosion; Carbon nanotubes; Carbon fibers; Polyhedral carbon nanofoams; Phosphonated hydrocarbon ionomer; Mass-transport losses; Electrode morphology; Electrode collapse; Start-up and shut-down; System strategies; Stainless steel; Bi-polar plates; In-situ contact resistance.;

   Abstract : The topic of this thesis is the degradation of fuel cell electrodes in proton exchange membrane fuel cells (PEMFCs). In particular, the degradation associated with localized fuel starvation, which is often encountered during start-ups and shut-downs (SUs/SDs) of PEMFCs. At SU/SD, O2 and H2 usually coexist in the anode compartment. READ MORE

7. 5. Adding Utility to Carbon Materials: Introducing Dopants Using Highly Soluble Metal Salts and Functionalizing Surfaces via Bromomethylation

   Author : Samuel Joseph Fretz; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; carbon materials; fuel cells; Li-S batteries; surface functionalization; doping;

   Abstract : Carbon-based materials have received intense research interest over the past few decades due to their unique  combination of properties including porosity, non-toxicity, chemical inertness, low density, and electrical conductivity, which has allowed them to find a wide array of applications including supercapacitors, batteries, CO2 capture, fuel cells, and catalysis. To expand their utility, a variety of techniques have been developed to enhance their reactivity and functionality. READ MORE