EFFECTS OF CHANNEL CROSS-SECTION GEOMETRY ON THE PERFORMANCE OF PEM FUEL CELLS

Abstract In this study, effects of the flow field cross-section geometry on the PEM fuel cell's performance investigated by using a three-dimensional numerical model. For this purpose, the fuel cells having rectangular, triangular, trapezoid and semi-elliptical channel cross-section geometry were modelled. When changing the channel geometry, one or more of the channel cross-sectional area sizes, channel height, channel width, flow collecting plate shoulder width and cell width sizes changed. Therefore, the influences of the flow channel cross-section geometry were examined for four different cases. With the change of channel geometry, in the first case, the cross-sectional area sizes are not taken equally. In the second case, by taking different channel heights, flow field area sizes were equalized. So as to equalize the sizes of the flow field area, in the third case, the channel widths and shoulder widths of current collector plate were taken different for each geometry. Lastly, in the fourth case, the widths of channels and cell were taken differently. Among the four studied cases, Case-4 is the case where the effect of the flow channel geometry is the most significant and the most pronounced. In Case 4, the cell voltage and power values obtained according to the varying channel section geometries can be sorted as triangle > semi-elliptical > trapezoid > rectangular.