Computational analysis of heat transfer in a PEM fuel cell with metal foam as a flow field

Abstract

Thermal management of proton-exchange membrane (PEM) fuel cell has an important effect on the overall cell performance. In this paper, metal foams as flow field are used to render more uniform temperature, gaseous reactants and current density distribution and also to reduce the mass and the cost of machining of flow-field channels and to enhance the performance of the PEM fuel cell. A 3-D model is considered and a set of equations including continuity, momentum, species, energy, and charge together with electrochemical kinetics are developed and numerically solved. A comparison is made between the PEM cell with metal foam and parallel channel as flow-field gas distributor. The results show that utilization of metal foam as flow field leads to increase in the reactant gas transfer and current density, and the current density distribution improves. The maximum temperature in the cell with metal foam is lower than conventional cell, and temperature distribution is more uniform within the cell. At low and middle current densities, the cell with metal foam has better performance than conventional channel due to lower temperature and lower ohmic resistance and this cell is more efficient at high current density due to lower mass transport losses. Furthermore, metal foam with high permeability provides a more uniform distribution of reactant gases with low pressure loss.