Investigation of the humidifierperformance of adding gas diffusion layers around membrane for fuel cell application

PEM fuel cells requires humidification the reactive gases before entering the fuel cell for good performance. Using a flat membrane humidifier with important advantages such as simple building, no need for electrical energy and no moving parts, is one of the best methods to humidification the reactive gases discussed in this paper. In this study, it is proposed to insert porous layers (gas diffusion layers) on both sides of the membrane, to increase the residence time gases. Therefore, by using three-dimensional and numerical modeling of the humidifier, the effect of porous layers and the effect of their properties on the humidifier performance are investigated. For this purpose, a non-porous humidifier is first modeled, and then the porous layer is inserting on the wet side, on the dry channel side, and on two sides of the membrane, and the performance of these models is compared. The results show that the highest dew point temperature of dry side outlet as well as the highest water flow rate of dry side outlet were related to the use of gas diffusion layers on both dry and wet sides, on the dry side, on the wet side and humidifier without gas diffusion layers respectively. In all cases of laying gas, with increasing porosity coefficient and permeability, dew point and water flow rate of dry side outlet increases and improve humidifier performance. The pressure drop on both dry and wet sides does not change significantly with the insert of the gas diffusion layer.