Two-phase modeling of mass transfer characteristics of a direct methanol fuel cell

A two-dimensional, two-phase mass transport model has been developed for a direct methanol fuel cell (DMFC). The model is numerically solved with a in-house code and validated with published experimental data in the literature. In particular, gaseous and liquid phase velocities in the anode porous structure are obtained so that the liquid-gas counter convection effect can be investigated. The numerical results show that the mass transfer of methanol is predominated by the resistance in the anode porous structure, which is affected by physical properties of the porous medium, such as porosity, permeability, and contacting angle. It is further shown that cell performance can be improved by increasing the porosity and permeability, and decreasing the contacting angle of the porous medium for a given feed methanol concentration.