The Effect of Obstacle Geometric Feature in Parallel Flow Field on PEMFC Output Performance

Abstract

Previous research has proven that the performance of proton exchange membrane fuel cells (PEMFC) can be enhanced by introducing barriers in the parallel flow field, which improved reactant transport and induced adequate reaction. However, existing research on the geometric parameters of obstacles was insufficient, especially for the design of obstacle shapes and the size of the angle of incidence. In this study, five different shapes of obstacles was introduced which were dispersed and placed in a parallel flow field. The effects of these different shaped obstacles on PEMFC output performance were compared by simulation. When reactants passed through the obstruction, the velocity increased, leading to higher concentration of reactants in the catalytic layer. This resulted in more complete, reaction and improved the output performance. The study demonstrated that incorporating 16 uniformly placed obstacles in the sub-flow channel of parallel flow field, it was concluded that the output power of the parallel flow field with right-angled trapezoidal obstacles was higher which was 0.57 W cm−2. The size of the right-angled trapezoidal cut-in angle was discussed. It was found that the right-angled trapezoidal obstacle with the cut-in angle of 30°, length of 1 mm, width of 0.3 mm, and height of 1 mm, the net power density was 0.57 W cm−2, which was improved 43%. And water removal capacity increased 16%. Current density of the new flow field was 14% higher than that of the interdigitated flow field.