Akademik Veri Yönetim Sistemi
STROJARSTVO, cilt.52, sa.5, ss.507-516, 2010 (SCI-Expanded)
In this study, fluid flow and concentration distribution on the cathode side of a Proton Exchange Membrane Fuel Cell were numerically analyzed. The problem domain consists of a cathode gas flow channel, cathode gas diffusion layer and cathode catalyst layer. The governing equations, continuity, momentum and concentration equations were discritized by the control volume method and solved using a computer program based on SIMPLE algorithm. Simulations were made for different values of gas diffusion layer porosity, catalyst layer porosity and the ratio of the cathode gas diffusion layer thickness to the gas flow channel height. Using the results of these simulations, the effects of these parameters on flow, oxygen concentration and current density distribution were analyzed. It is observed that increasing the porosities of the gas diffusion layer and catalyst layer increases the current and power densities. The increase in the porosity of the gas diffusion layer also increases the oxygen concentration in both gas diffusion and catalyst layers but decreases the oxygen concentration in gas flow channel. Simulations also showed that increasing porosity of the catalyst layer increases the oxygen concentration in a catalyst layer but decreases the oxygen concentration in a gas flow channel and gas diffusion layer. It is also seen that the effect of the gas diffusion layer porosity is more dominant on cell performance compared to the catalyst layer porosity. The analysis of the effect of the ratio of the cathode gas diffusion layer thickness to the gas flow channel height on the cell performance showed that the increasing ratio of the cathode gas diffusion layer thickness to the gas flow channel height decreases the current and power densities. An analysis of the data obtained from simulations also shows that increasing the ratio of the cathode gas diffusion layer thickness to the gas flow channel height increases the oxygen concentration in the gas flow channel but decreases the oxygen concentration in both gas diffusion and catalyst layers.