A CFD Analysis of Transport Phenomena and Electrochemical Reactions in a Tubular-shaped Ambient Air-breathing PEM Micro Fuel Cell

Abstract

The development of physically representative models that allow reliable simulation of the processes under realistic conditions is essential to the development and optimisation of fuel cells, the introduction of cheaper materials and fabrication techniques as well as the design and development of novel architectures. 3-dimensional, multi-phase, non-isothermal CFD model of a novel, simple to construct, tubular, air-breathing PEM micro fuel cell which work 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 account for the major transport phenomena in a tubular-shaped air-breathing PEM micro fuel cell: convective and diffusive heat and mass transfer, electrode kinetics, transport and phase-change mechanism of water, and potential fields. The model is shown to understand the many interacting, complex electrochemical and transport phenomena that cannot be studied experimentally. Fully 3-dimensional results of the velocity flow field, species profiles, temperature distribution and water content profile in the membrane are presented and analysed with a focus on the physical insight and fundamental understanding. They can provide a solid basis for optimising the geometry of the PEM micro fuel cell stack running with a passive mode.