Numerical simulations of anode two-phase flow in Micro-DMFC using the volume of fluid method

Abstract

Two-phase flow phenomena occur in low temperature Direct Methanol Fuel Cells (DMFC) through the generation of CO2 gaseous bubbles at the anode side, and/or due to the accumulation of water droplets at the cathode side. In order to achieve better cell performances, two-phase flow characterization is crucial when designing these devices. Numerical models are a helpful tool in this characterization process. In this work, a Computational Fluid Dynamic (CFD) model using the Volume of Fluid (VOF) method is applied to describe the two-phase flow CO2/methanol solution occurring at the anode side of a Micro-DMFC. As far as the authors are aware, an entire channel geometry (serpentine) of a real Micro-DMFC is, for the first time, used in the simulations. The effects of the CO2 and methanol solution inlet velocities through the pores mimicking the diffusion layer interface and of temperature on the two-phase flow patterns are analyzed. The presented results reveal that the VOF method can be applied successfully using an entire geometry instead of a single channel geometry.