Bio inspired channel design and optimization intended for water and heat management in PEM fuel cells

In the conversion of hydrogen into electrical energy as result of electrochemical reactions, Proton Exchange Membrane (PEM) fuel cells emerges as an ideal energy conversion system especially for mobile systems with its low operating temperature, rapid startup and high power density features. However, PEM fuel cells need to be strengthened in terms of negative consequences such as flooding, drying and hotspot formation. Within the scope of this thesis, it is aimed to solve these problems with bio-inspired flow fields developed by taking advantage of the geometric properties of biological structures and the adaptations of livivg things. Three new flow field patterns have been developed. These are intermediate reservoir and intermediate feeding flow fields developed based on the reflexes of mammalian circulatory systems under hypoxia and the honeycomb flow area, which is inspired by the shape of the honeycombs of bees. Additionally, four-channel serpentine flow field was tested under different temperature and pressure effects as a reference. In intermediary feeding flow field, the reactant feed points and feed rates were accepted as variable and the optimum operating conditions were determined experimentally. While explaining the results, numerical analysis made with Ansys Fluent PEM Fuel Cell module were used if needed. It was determined that intermediate reservoir flow field has 10% higher power density than four-channel serpentine flow field. The symmetrical or asymmetric feeding from anode and cathode doesn't correspond to a correlation which one of them leading maximum performance permanently. Application of feed rates both on anode and cathode provided higher power density than the asymmetric feeding in intermediate feeding. Honeycomb flow area with direct flow has the highest performance among all.