Experimental and numerical investigation of the effect of different flow field design on fuel cell performance

In this thesis, a study was carried out on the optimization of numerical, experimental and geometric parameters with regard to flow channels on bipolar plates which constitute 80% by weight of the fuel cell. During the design and experiments, Membrane Electrode Group (MEA) was prepared in our laboratory and the same MEA was used in all experiments. Within the scope of experimental study; the fuel cell with single serpantine type flow field, which is currently used in the literature, was manufactured. That fuel cell was tested at the fuel cell temperature of 70 °C, 1 atm pressure, 100% humidification and a flow rate of 0.25 lt/min. The same geometry was analyzed numerically and the numerical model was verified comparing the results with experimental data. In order to improve the performance of the fuel cell with conventional single-serpentine flow field, four unique flow fields were designed and firstly tested numerically and then experimentally. The effect of the geometric parameters on the most efficient design to be investigated numerically, the channel height, the channel width and the flow area/contact surface ratio were analysed using Response Surface Methodology. The optimum channel geometry was obtained for the target functions which would make the maximum current density and minimum pressure drop. The performance of this geometry was determined experimentally by changing the fuel cell temperature and flow rate. The current density in fuel cells having the flow field designed and oprimized with the scope of this study has increased by 22.9% compared to the traditional single serpantine type fuel cell.