A physics-based, system-level framework is developed to quantify air processing system (APS) strategies that govern internal fuel cell water management and overall systematic behavior. Air-side components are developed with coupled heat and mass trans...
A physics-based, system-level framework is developed to quantify air processing system (APS) strategies that govern internal fuel cell water management and overall systematic behavior. Air-side components are developed with coupled heat and mass transfer characteristics, including a fuel cell stack that involves condensation, a counter-flow membrane humidifier, and a centrifugal compressor. The stack model is validated against published experimental data. Furthermore, these numerical models are integrated on a piping and instrumental diagram to predict thermodynamic states. Subsequently, parametric studies were conducted on cathode pressure and stoichiometry ratio to determine the membrane-averaged relative humidity (RH), the channel outlet liquid fraction, and humidifier water supply relative to the required stack water mass flow rate. The results showed that a high-pressure/low-stoichiometry strategy could sustain membrane saturation even at low inlet RH, and could reduce humidification demand by 13%. This integrated framework could provide operating maps and design guidance to optimize APS water management.