CFD Analysis of PEMFC Flow Channel Cross Sections

Abstract

This paper presents a study of single‐channel proton exchange membrane fuel cells (PEMFCs) using computational modeling and simulation. For this analysis, the commercial software COMSOL Multiphysics was used to build a single‐phase isothermal and tridimensional fuel cell model. For the mathematical description of the catalyst layer, the flooded agglomerate model was implemented, and it proved to be more accurate than Butler‐Volmer model, which is the pre‐built model in the software. Such evidence was verified when comparing the polarization curves obtained using both models with an experimental curve. After definition of the model, the main objective of this study was to analyze the influence of the flow channel cross‐section in the water distribution inside the cell, studying rectangular, trapezoidal and hybrid stepped geometries. The fuel cell with stepped channel was equivalent to the trapezoidal cell in all aspects analyzed, and both provided superior water management than the rectangular cell. However, the current generation in the rectangular design was slightly higher. It was noted that the simulation of a tridimensional model provided a better understanding of the regions where higher concentrations of water can occur, and that different flow channel designs can be used to enhance water management.

Shape Optimization of PEMFC Flow‐channel Cross‐Sections

“…In order to perform this validation, the present simulation was compared to experimental and numerical simulation results presented by Paulino et al [6]. In order to perform this validation, the present simulation was compared to experimental and numerical simulation results presented by Paulino et al [6].…”

“…Regarding the numerical simulation results, both of them had the same parameter values and the only difference was that this study employed a tetrahedral mesh (161,747 elements) and the comparison study [6] used a hexahedral mesh (13,920 elements). The present polarization curves compared well with the results provided by Paulino et al [6]. Figure 2 shows the polarization curves of PEMFCs with rectangular cross-section flow channels, comparing numerical simulation and experimental results.…”

“…The model consists of agglomerates composed by ionic conducting phase (electrolyte) and electrically conducting nanoparticles (electrodes), forming a cluster or agglomerate wrapped in catalyst [6,14,15]. Besides that, the electrochemical reactions are used to validate the numerical model against a real fuel cell.…”

“…Among the geometric parameters, the cross-section of the flow-channel was investigated by using experimental [3] and numerical [4][5][6] methods. The cross-section is commonly rectangular, but other geometries such as triangular, trapezoidal, stepped and semi-circular have been investigated [3,5,6].…”

“…The cross-section is commonly rectangular, but other geometries such as triangular, trapezoidal, stepped and semi-circular have been investigated [3,5,6]. Paulino et al [6] concluded that rectangular cross-section channels had higher electric performance, but the trapezoidal (and stepped) cross-section showed better water management characteristics, which was a result also found experimentally by Freire et al [3]. Paulino et al [6] concluded that rectangular cross-section channels had higher electric performance, but the trapezoidal (and stepped) cross-section showed better water management characteristics, which was a result also found experimentally by Freire et al [3].…”