Modelling Methods and Validation Techniques for CFD Simulations of PEM Fuel Cells

Abstract

The large-scale adoption of fuel cells system for sustainable power generation will require the combined use of both multidimensional models and of dedicated testing techniques, in order to evolve the current technology beyond its present status. This requires an unprecedented understanding of concurrent and interacting fluid dynamics, material and electrochemical processes. In this review article, Polymer Electrolyte Membrane Fuel Cells (PEMFC) are analysed. In the first part, the most common approaches for multi-phase/multi-physics modelling are presented in their governing equations, inherent limitations and accurate materials characterisation for diffusion layers, membrane and catalyst layers. This provides a thorough overview of key aspects to be included in multidimensional CFD models. In the second part, advanced diagnostic techniques are surveyed, indicating testing practices to accurately characterise the cell operation. These can be used to validate models, complementing the conventional observation of the current–voltage curve with key operating parameters, thus defining a joint modelling/testing environment. The two sections complement each other in portraying a unified framework of interrelated physical/chemical processes, laying the foundation of a robust and complete understanding of PEMFC. This is needed to advance the current technology and to consciously use the ever-growing availability of computational resources in the next future.

Parameter Identification of a Quasi-3D PEM Fuel Cell Model by Numerical Optimization

“…Developing more sophisticated models with, e.g., anisotropic material properties, agglomerate models for CL or gas crossover in the membrane further exacerbates the problem. The measurement methods to determine the necessary parameters are complex, expensive, and specialized equipment is often needed, e.g., the porosity of the GDL can be measured via 3D XCT methods, see [19]. This work demonstrated the efficient parameterization of a single-phase, isothermal PEMFC model with measurements on a stack.…”

“…For the fluid flow through porous media, the porosity is crucial. As shown by Karpenko-Jereb et al [22] and d'Adamo et al [19] the porosity of the GDLs has a significant influence on the species transport, electric conductivity and, therefore, current density. Thus, the porosity was added to the design variables for numerical optimization.…”

“…The effective electrical conductivity is a function of the bulk electrical conductivity and the porosity of the GDL. Several different relationships can be found in the literature, see in [19]. As proposed by Bruggeman [50] and adapted by Das et al [59] the relationship of effective and bulk conductivity can be given with…”

“…This value is close to the result of the numerical optimization procedure. The tortuosity of the GDL is mostly unknown, thus several relationships exist in the literature to determine it from the porosity of the material, see in [19]. A value of about τ GDL,expected = 1.38 could be expected from the optimization process by applying the schemes on the determined porosity.…”

“…As pointed out by Demuren and Edwards [4] and d'Adamo et al [19], the detailed measurements to determine the geometric, chemical, and physical characteristics of the PEMFCs' materials is a complex and time-consuming task. In addition, many of the measurement methods are ex situ and even destructive.…”