Modeling of flow and transport processes occurred in a typical polymer electrolyte membrane fuel cell (PEMFC)

Abstract. In the present work, a three dimensional model examining the fluid flow along with the fundamental transport phenomena occurring in a typical polymer electrolyte fuel cell (PEMFC), i.e. heat transfer, mass transport and charge transfer, has been developed. The flow field was simulated according to the well known Navier-Stokes equations, while the heat transfer was described by the typical conduction/convection equation and the mass transport by the convection/diffusion one. Furthermore, reaction kinetics were studied by the Butler-Volmer equation for the heterogeneous reactions occurring at the porous electrodes. The developed model was numerically solved by using the commercially available CFD package CFD-RC © , which is based on the multi-step finite volume method. The fuel cell performance in terms of velocity, temperature, mass fractions of active compounds and electric field has been investigated as well. Introduction Fuel cell systems are energy devices that directly convert the chemical energy of the feeding fuel into electricity without Carnot limitation, being suitable for stationary and mobile applications. Due to the high conversion efficiencies and the negligible environmental impact, fuel cell technology is considered as one of the most promising to contribute essentially to generation of electrical power in the near futur

Surface Roughness Optimization of Poly-Jet 3D Printing Using Grey Taguchi Method

In the current study, the surface finish of specimens fabricated with PolyJet 3D Printing Direct process is discussed. Three surface roughness indicators were measured at three positions, while three process parameters namely layer thickness, build style and scale were examined. An L4 orthogonal array was employed for the design of experiments. Grey-Taguchi method was applied in order to optimize all surface roughness parameters. The effect of each parameter has been investigated using ANOM (Analysis of Means), while ANOVA (Analysis of Variances) has been performed to identify each parameter importance onto the surface texture. Additionally, the findings of this study were compared with the results of a similar optimization study conducted before, using the usual Taguchi method. It was concluded that 16 μm of layer thickness and glossy style provide the optimum surface roughness results, while built style is the most dominant factor. All the results of the Grey Taguchi method are compatible with the ones of the usual Taguchi method. © 2019 IEEE

From biomass to electricity through integrated gasification/SOFC system-optimization and energy balance

In this paper the integrated process of biomass gasification and a solid oxide fuel cell (SOFC) was studied in terms of thermodynamics. The study is based on an ongoing project intending to develop an innovative sustainable technology with high efficiency. According to some assumptions, the energy balance revealed that the process can be auto-thermal. Furthermore, and due to the utilization of the hydrogen content of steam utilized in the reforming stage, the overall efficiencies to electrical power could reach very high levels. © 2006 International Association for Hydrogen Energy