Computational Fluid Dynamics (CFD) and Neutron Imaging (NI) for PEM fuel cells

<p>Alfredo Iranzo and Elvira Tapia</p>

Computational Fluid Dynamics (CFD) and Neutron Imaging (NI) for PEM fuel cells

Alfredo Iranzo and Elvira Tapia

University of Sevilla, Spain

: J Nucl Ene Sci Power Generat Technol

Abstract

Optimal water management in PEM fuel cells is still one of the main challenges in fuel cell design and operation, with significant research efforts being carried out both by industry and academia. Two major approaches are used for the investigation of water balance in fuel cells: Experimental testing and numerical modelling, the latest presenting a significant contribution of Computational Fluid Dynamics (CFD) tools. This work presents research activities carried out in the field of PEM fuel cells water management research, where both CFD and liquid water visualization by means of neutron imaging are used. First, a validation work of a three dimensional CFD 50 cm2 PEM fuel cell model is presented, which is particularly focused on the prediction of liquid water distributions within the cell. Beyond the comparison of the polarization curves, an in-depth validation is presented by also comparing the local liquid water distributions predicted by the model with the liquid water distributions of the real cell measured by means of neutron imaging, for a set of different operating conditions. A model validation approach using local variable distributions (such as liquid water in this case) in addition to the integral quantities (i.e. polarization curves) is necessary to ensure the validity of models. In addition, novel CFD modelling frameworks for the simulation of the diffusive mass transport occurring at GDL local scale is presented, in particular in relation with the distribution of liquid water in the porous media. The distinctive characteristic of this framework is the fact that the distribution of liquid water is not predicted by the model but it is instead mapped into the simulation model from available experimental measurements, obtained with Neutron Imaging. The presence of liquid water is thus included in the model as a modifier for the gas diffusion transport, and not directly calculated by the model. This allows for a coupling of experimental measurements and model development that is expected to allow a further progress of highly reliable models for the understanding of local fuel cell phenomena.