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Degradation of Fuel Cell (FC) components under dynamic loads is one of the biggest bottlenecks in FC commercialization. A novel experimental based model is presented to predict the Catalyst Layer (CL) performance loss under a given cyclic load. It consists of two sub-models: Model 1 computes CL Electro-Chemical Surface Area (ECSA) under an N-cyclic load with aid of an analogy with fatigue phenomena of carbon steel by using some correction factors. Ostwald ripening of agglomerate particles in the CL is also modeled. Model 1 validation shows good agreements between its outputs and a large number of experiments with maximum 7% error. Model 2 is an already-completed task in an earlier study which uses the agglomerate model to calculate the CL performance for a given ECSA. Combination of Models 1 & 2 predicts the CL performance under a dynamic load. A set of parametric studies was performed to investigate the effects of operating parameters on the Voltage Degradation Rate (VDR). The results show that temperature is the most influential parameter; that an increase from 60oC to 80oC leads to 20.26% VDR increase, and pressure is the least effective one; that an increase from 2atm to 4atm leads to 1.41% VDR rise.

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Recently, in many fuel cell applications, foam is being used as a flow distributor to increase efficiency and achieve a more uniform distribution of reactants on the active surface. However, despite the improvement in the efficiency and performance of the fuel cell, this method does not fully achieve the desired uniformity in reactant distribution. Therefore, in this study, non-uniform porosity metal foam has been utilized to improve the homogeneous flow distribution on the cathode side of the PEM fuel cell. At first, the foam is assumed to be uniform with the same porosity. After the numerical solution of the flow in homogeneous foam (first type), Two types of foam with variable porosity coefficient have been designed. These foams are divided into checkerboard shape, where the porosity coefficients in the concave corners (dead areas) with low molar fraction of oxygen are higher. This facilitates easier movement of the flow towards these corners, resulting in a more uniform flow distribution. the simulation results indicate that, for a constant current density, the distribution of the mole fraction of oxygen in both types of foam with a variable porosity coefficient has become more uniform. Additionally, the average molar fraction of oxygen has increased by 9.45% in the second type of foam and by 32.02% in the third type of foam compared to the uniform foam, which indicates an increase in generated power. Also, compared to the uniform foam, the pressure gradient in the foam with variable porosity of the second type increased by 75.80%, while it remained relatively unchanged for the third type foam.