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Herein, for the first time, a computational fluid dynamic study is performed to investigate the effects of using porous carbon inserts (PCI) on the performance of PEMFC. A 3D multiphase multicomponent model is developed to simulate the fuel cell performance. The effects of several geometric and physical parameters of the PCI, including porosity, size, and the arrangement of PCI in the landing area, are numerically examined, which are not investigated in the literature so far. The numerical results showed that using PCI, a 23% improvement in the fuel cell performance is achieved for the optimum case with 80% PCI. In addition, increasing the PCI porosity results in performance enhancement (12.6% improvement when increasing the porosity up to 0.8). Using PCI with different rib/channel width ratios demonstrates that the use of PCI at higher ratios has a more significant effect. When using 34.1% PCI in a case with a ratio of 2:1, the performance increases about 35%. Moreover, a PCI with larger longitudinal size (4 mm compared to 2 mm) shows higher performance enhancement (5.3% compared to 3.5%).

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This study discusses turbulent suspension flows of non-Brownian, non-colloidal, neutrally buoyant and rigid spherical particles in a Newtonian fluid over porous media with particles too large to penetrate and move through the porous layer. We consider suspension flows with the solid volume fraction ${{\varPhi _b}}$ ranging from 0 to 0.2, and different wall permeabilities, while porosity is constant at 0.6. Direct numerical simulations with an immersed boundary method are employed to resolve the particles and flow phase, with the volume-averaged Navier–Stokes equations modelling the flow within the porous layer. The results show that in the presence of particles in the free-flow region, the mean velocity and the concentration profiles are altered with increasing porous layer permeability because of the variations in the slip velocity and wall-normal fluctuations at the suspension-porous interface. Furthermore, we show that variations in the stress condition at the interface significantly affect the particle near-wall dynamics and migration toward the channel core, thereby inducing large modulations of the overall flow drag. At the highest volume fraction investigated here, ${{\varPhi _b}}= 0.2$ , the velocity fluctuations and the Reynolds shear stress are found to decrease, and the overall drag increases due to the increase in the particle-induced stresses.

Flow field design is crucial for achieving higher performance in polymer electrolyte membrane fuel cells (PEMFCs). This study uses a two‐phase, multi‐component, and three‐dimensional model to simulate the performance of PEMFCs that use interdigitated flow field design with intermediate blocks on the cathode side. A detailed parametric study is presented to investigate the effects of various geometric and operational parameters. Of the parameters studied, inlet mass flow rate, relative humidity, and rib width had the greatest impact on cell performance. The results show that increasing the cathode stoichiometric ratio resulted in higher fuel cell performance for blocked interdigitated designs compared to parallel designs. In addition, using cathode channels with higher height values resulted in lower PEMFC performance for all flow fields. Higher values of rib/channel width ratio resulted in lower cell performance due to liquid water accumulation in the rib regions. However, at higher rib/channel width ratios, the positive effect of using interdigitated flow designs was more pronounced. Moreover, at a low relative humidity of RH = 25%, a 10.4% higher performance was obtained for the interdigitated type II compared to cases with RH = 100%, due to more effective over‐rib convection and higher water removal.