Research On Flow Field On Bipolar Plates For Proton Exchange Membrane Fuel Cell

Bipolar Plate is one of most important part in PEMFC; they are greatly influential to cell performance because the flow-field structure decides the flow pattern of the reactants and product, heat transfer, and the long-run stability of fuel cell. The work in this thesis focuses on the effects of two kind of flow-field geometric structure on cell performance.In this thesis, a there-dimensional, comprehensive, steady-state mathematical model is described to investigate the fluid flow, species transport and electrochemical reaction in the PEM fuel cell. The studied domain consists of fluid channels, diffusion layers and catalyst layers of cathode. The transport phenomena occurs in the cathode bipolar plate is described by the generalized equation, and different physical parameters and source terms are employed for different layers. The flow characteristics, mass transport in the 3-D space are obtained by resolving the transport equation, and coupling the electrochemical kinetics equations. The general different equations are solved by method based on volume control finite discrete CFD technique with Fluent software. Then gain the flow performance of the fluid and the distribution of the reactant and production in the cell. Analyze the influence of the current density and reactant inlet velocity for the gas transfer and distribution. And discuss the influence of the structure of interdigitated and parallel flow-field for the gas flow and transfer. In the experiment, we test two flow-fields with the same MEA and discover that the interdigitated flow-field can improve the gas transfer velocity, enhance the maximum current density and reduce the cell polarization. In this situation, the fuel cell performance will be improved.