A Two-Phase Pressure Drop Model Incorporating Local Water Balance and Reactant Consumption in PEM Fuel Cell Gas Channels

A two-phase 1-D pressure drop modeling scheme that incorporates the effect of local channel saturation on flow regime is introduced. The model provides a basis for extending two-phase pressure drop correlations from fundamental studies to more complex conditions within PEMFC reactant channels. The need for additional studies beyond the fundamental level is highlighted and key factors that separate PEMFC reactant channel conditions are explained. A crucial concern in characterizing two-phase flow within PEMFC reactant channels is the local flow pattern transitions throughout the channel. The application of an elemental step-wise calculation scheme approach for the prediction of localized two-phase conditions allows for a more complete prediction of conditions within the channels. Additionally through the application of a control volume approach, the effect of water addition and mass consumption of reactants on pressure drop within PEMFC flow channels is investigated. The resulting modeling scheme shows the relative effects of relaxing several of the common assumptions made when modeling PEMFC reactant channels.