Three-dimensional computational fluid dynamics model of a tubular-shaped ambient air-breathing proton exchange membrane fuel cell

The development of physically representative models that allow reliable simulation of the processes under realistic conditions is essential for the development and optimization of fuel cells, the introduction of cheaper materials and fabrication techniques, and the design and development of novel architectures. A three-dimensional, multi-phase, non-isothermal computational fluid dynamics model of a novel, simple to construct, tubular, proton exchange membrane (PEM) fuel cell which works in still or slowly moving air has been developed. The novel tubular geometry enables optimum air access to the cathode without the need for pumps, fans, or similar devices. This comprehensive model accounts for the major transport phenomena such as convective and diffusive heat and mass transfer, electrode kinetics, transport and phase-change mechanism of water, and potential fields in a tubular-shaped air-breathing PEM fuel cell. The model explains many interacting, complex electrochemical, and transport phenomena that cannot be studied experimentally. Three-dimensional results of the species profiles, temperature distribution, potential distribution, and local current density distribution are presented and analysed, with the focus on the physical insight and fundamental understanding. These results provide a solid basis for optimizing the geometry of the PEM fuel cell stack running in a passive mode.