Numerical Study on the Effect of the Combined Radial Flow Field on the Performance of Proton Exchange Membrane Fuel Cells

As the flow field structure has a crucial influence on the performance of the proton exchange membrane fuel cell, in this research, the radial flow field R-0 is designed and optimized based on the characteristics of the annular serpentine and annular flow channels to form combined flow field structure (R-1 to R-5). Subsequently, a three-dimensional and two-phase model is established and the effects of each flow field on the cell performance are numerically investigated. Results indicate that the R-0 can enhance the gas vertical velocity on the diffusion-catalyst interface compared to the parallel flow field, which increases the effective concentration of reaction gases within the catalyst layer, thereby accelerating the electrochemical reaction rate, and the performance of the combined flow fields is further improved. In addition, the effect of the percentage of annular serpentine within the combined flow field on the concentration distribution, uniformity, and output performance is analyzed. Results indicate that increasing the percentage of annular serpentine structure can increase the pressure between adjacent channels, and thus the higher pressure and concentration gradient generated can enhance the gas transport and reduce the water accumulation under the ribs thus effectively improving the cell performance.