A CRITICAL OVERVIEW OF COMPUTATIONAL FLUID DYNAMICS MULTIPHASE MODELS FOR PROTON EXCHANGE MEMBRANE FUEL CELLS

This paper presents an overview of the mathematical issues and the current situation in the computational fluid dynamics (CFD) modeling of multiphase transport in hydrogen-operated proton exchange membrane fuel cells (PEMFCs) at a macroscopic scale. The paper overviews multiphase models which are based on the finite volume approach and which cover water transport from anode to cathode throughout the membrane electrode assembly ( MEA). We review conceptual models of water transport in the diffusion media focusing on the formulation of the balance equations and of the constitutive relations and discuss weaknesses and inconsistencies of current approaches based on experimental and theoretical evidence. A major incentive of this review is to stress the impact on water management of the widely ignored phenomena at the subgrid-scale distributed interfaces and at the macroscopic-scale interfaces between the fuel cell components. We discuss how misinterpretation of the physical meaning of various terms in the macroscopic transport equation of water in catalyst coated membranes (CCMs) might have led to faulty numerical treatments of this equation. We also recommend new evolving approaches.