Two dimensional numerical modeling of a membrane humidifier with porous media flow field for PEM fuel cell

A membrane humidifier with porous media flow field (metal foam) can provide more water transfer, low manufacturing complexity and low cost in comparison with the conventional humidifier. In this study, a two-dimensional numerical model is developed to investigate the performance of the humidifier with porous metal foam. The results indicate that the dew point increases with a decrease in the permeability, but at permeabilities lower than 10-8 the pressure drop increases extremely. At all ranges of pressures, temperatures and flow rates of humidifier inlet, the pressure drop in humidifier with porous media flow field is only about 0.5 kPa higher than that of the conventional humidifier, which is not significant and it can be ignored. An increase in the pressure at dry side inlet and wet side inlet of the humidifier results in a better humidifier performance. Humidifier performs better at high flow rates and temperatures of humidifier wet side inlet. At all ranges of pressures, flow rates and temperatures humidifier with porous metal foam indicates better performance.