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Proton exchange membrane fuel cell (PEMFC) is the most important system that converts chemical energy into electricity by using hydrogen oxidation and oxygen reduction reactions. With this approach, a 3-D (CFD) thermo-fluid model was studied using a commercial code ANSYS fluent for investigating the performance of the PEMFC system. The developed model can evaluate the distribution of gas species like the mass fraction of hydrogen, as well as the distribution of water in PEMFC. The results are used to investigate the influence of temperature and cell voltage on the consumption of hydrogen from inlet z= 0mm to outlet z=50 mm. The obtained polarization curve I-V is compared with the literature findings. The analysis shows a good agreement between our findings and the experimental results. The CFD simulation shows that the cell voltage affects considerably the hydrogen consumption; at 333 K, it can be seen that the hydrogen mass fraction decreases from 80% to 67% at 0.7 V and 80% to 73 % at 0.9 V. By comparing the hydrogen mass fractions; at a low cell voltage the hydrogen mass fraction dropped by only 7%, while at a high cell voltage the hydrogen mass fraction dropped by about 13% from the inlet to outlet. Consequently; our analyses show high consumption of hydrogen at low cell voltages.

In this study, a Finite Element model has been implemented based on numerical modelling simulations to predict the mechanical behaviour of a representative unit of the fuel cell stack. The GDL deformation has been modelled as a combination of elastic deformation and fibres slippage. Mechanical stresses distribution and deformation are presented concerning the previous model work l with nonlinear orthotropic behaviour of the GDL. The results also show that the state of the stresses in the membrane are highly heterogeneous and largely exceed its elastic limit. The results show that the influence of the temperature variation is not significant in generating stresses. However, the influence of the moisture variation is very significant in generating stresses. Therefore, the increase in relative humidity from 30% to 90° % at T=25°C causes an increase in the maximum Von Mises stress of 0.0836MPa.

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