The present study proposes a modified serpentine flow field design in which the channel heights vary along each straight flow path to enhance reactant transport and liquid water removal.An optimization approach,combin...The present study proposes a modified serpentine flow field design in which the channel heights vary along each straight flow path to enhance reactant transport and liquid water removal.An optimization approach,combining a simplified conjugate-gradient method(inverse solver)and a three-dimensional,two-phase,non-isothermal fuel cell model(direct solver),has been developed to optimize the key geometric parameters.The optimal design has tapered channels for channels 1,3 and 4 and increasing heights for channels 2 and 5 with the flow widths first increasing and then decreasing.The optimal channel heights and widths enhance the efficiency by 22.51%compared with the basic design having all heights and widths of 1 mm.The diverging channels have a greater impact on cell performance than fine adjustments of the channel widths for the present simulation conditions.The channel heights have more effect on the sub-rib convection,while the channel widths affect the uniformity of the fuel delivery more.The reduced channel heights of channels 2–4 significantly enhance the sub-rib convection to effectively transport oxygen to and liquid water out of the diffusion layer.The final diverging channel prevents significant leakage of fuel to the outlet via sub-rib convection.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.50876009)the Engineering Research Institute Foundation of USTB
文摘The present study proposes a modified serpentine flow field design in which the channel heights vary along each straight flow path to enhance reactant transport and liquid water removal.An optimization approach,combining a simplified conjugate-gradient method(inverse solver)and a three-dimensional,two-phase,non-isothermal fuel cell model(direct solver),has been developed to optimize the key geometric parameters.The optimal design has tapered channels for channels 1,3 and 4 and increasing heights for channels 2 and 5 with the flow widths first increasing and then decreasing.The optimal channel heights and widths enhance the efficiency by 22.51%compared with the basic design having all heights and widths of 1 mm.The diverging channels have a greater impact on cell performance than fine adjustments of the channel widths for the present simulation conditions.The channel heights have more effect on the sub-rib convection,while the channel widths affect the uniformity of the fuel delivery more.The reduced channel heights of channels 2–4 significantly enhance the sub-rib convection to effectively transport oxygen to and liquid water out of the diffusion layer.The final diverging channel prevents significant leakage of fuel to the outlet via sub-rib convection.
