CFD Analysis of Fuel Cell Humidification System for Automotive Application

Fuel cells are considered one of the promising technologies as possible replacement of Internal Combustion Engine (ICE) for the transportation sector due to their high efficiency, ultra-low (or zero) emissions and for the higher drive range. The Membrane Electrode Assembly (MEA) is what mainly influences the Fuel Cell FC performance, durability, and cost. In PEMFC the proton conductivity of the membrane is a function of the humidification level of the FC membrane, hence the importance of keeping the membrane properly humidified to achieve the best possible fuel cell performance. To have the optimal water content inside the fuel cell’s membrane several strategies could be adopted, dealing with the use of external device (such as membrane humidifier) or to adopt an optimal set of parameters (gas flow rate and temperature for example) to use the water produced at fuel cell cathode as humidity source. The aim of this paper is to study the behavior of a FC vehicle humidification system. Starting from experimental tests properly made with a commercial system, two different designs of the humidifier have been proposed. For both solutions, a CFD model has been developed to analyze the pressure drop and velocity. The membrane is modeled as a porous media to reduce the computational cost of the virtual CFD simulation. The simulation results have allowed to compare the two different proposed designs, performing a sensitivity analysis of the expected performances of the humidifier itself.