The performance of proton exchange membrane (PEM) fuel cell is greatly hinged on effective distribution of reactant species concentration in the system which subsequently determines distribution in local current density, temperature and water over the area of PEM fuel cell. Flow-field geometry optimization can effectively insure proper distribution of reactants to eliminate the build-up stresses within different regions of the fuel cells that leads to effects such as flooding or drying of the membrane. In this work, a numerical investigation was conducted to analyse the flow field and reactant gas distribution in a PEM fuel cell channel with transversely inserted pin fins in the channel flow. The impact of the fin disturbances on reactant gas transport and fuel distribution on the GDL was investigated. A prerequisite for an efficient fuel cell system is a uniform distribution of reactants to every cell in the fuel cell stack. A fin configuration of small hydraulic diameter and high volume porosity (ratio of volume not occupied by fins) is employed to reduce the additional pressure drop. The influence of the pin fin parameters, fuel flow Reynolds number and the gas diffusion layer (GDL) porosity on the reactant gas transport through the GDL and the pressure drop across the channel length are explored. The parameters examined were optimized using a mathematical optimization code integrated with the commercial computational fluid dynamics code. The results obtain indicate that for a consideration of high performance and considerable pressure drop in a PEM fuel cell, pin fin insert in the channel flow greatly enhances fuel cell performance when compared with channel without pin fin and optimal pin fin geometries exist for minimized pressure drop along the PEM fuel cell channel studied. The results obtained will complement the generic information needed for improving the PEM fuel cell design.

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