Numerical Investigation of Convergent and Divergent Parallel Flow Fields for PEMFCs

Abstract

AbstractIn this study, the classical parallel flow field pattern is modified by a convergent and divergent design concept for proton exchange membrane fuel cells (PEMFCs). The modification is achieved by varying the channel depth with different constant inclination gradients from the inlet to the outlet, along with the bipolar plate width which creates either a convergent or divergent flow field depending on the position of the inlet and outlet selected. The numerical model is solved to predict the cell performance including the mass transport, water vapor concentration and, pressure and current density distribution for the flow fields. The numerical results reveal that the modified convergent parallel flow fields have a better mass transport and water removal characteristics than those in the conventional one, whereas mal‐distribution of species and excessive water concentration occur in the conventional and divergent parallel flow fields. Introducing convergent parallel flow field design concept not only minimizes these issues but the cell power density is also improved by a maximum of 16%, which can show a new window in PEMFC flow field design concept.