Experimental and numerical study on the water transport behavior through Nafion® 117 for polymer electrolyte membrane fuel cell

A novel model explaining the water transport mechanism through Nafion® 117 is developed to understand the effects of parameters such as phase difference, pressure, mass flow rate, and temperature for applying polymer electrolyte membrane (PEM) fuel cell application. The model considers water uptake characteristics based on the polymer membrane structure and adopts four different processes to explain water permeability considering interfacial transport across the boundary. To understand the effect of phase difference, we change the relative humidity at each inlet of the experimental apparatus from 10% to 100%. The results suggest that capillary pressure is the most dominant factor in water transport across the membrane. When we change the pressure at each side of the apparatus from 1 to 3 bar, the water transport amount is maximized at 1 bar for each inlet. The mass flow rate varies from 1 to 5 Lpm. Owing to changes in molar concentration, the amount of water transport is increased when the mass flow rate at dry side inlet is minimized. Moreover, the temperature effects on the water transport amount is analyzed. As the temperature increases, the amount of water transport at the dry and wet side outlet is increases and decreases, respectively, because of the interaction between diffusivity and surface tension. The above results are verified using measured data and compared with calculated results obtained by a conventional method. In the end, this study developed the empirical equation which can be used in the fuel cell model.