Iv Congreso Nacional De Pilas De Combustible 1/4 Characterization, Development and Experimental Validation of a Dynamic Model of an Open Cathode Pem Fuel Cell

RESUMEN: La distribución del agua en una PEMFC afecta su comportamiento y durabilidad, por tanto la comprensión de los mecanismos fundamentales del transporte del agua es imperativa y pueden ser fuertemente influenciados mediante estrategias apropiadas de control. Se ha desarrollado un modelo dinámico, no isotérmico, bidimensional de una PEMFC autohumidificada y de cátodo abierto. El modelo consta de tres submodelos usando el balance de energía, el balance de flujos y el balance másico de agua en el sistema, referidos al ánodo, cátodo, capas de difusión y la MEA. El modelo ha sido desarrollado para ser utilizado en la simulación y el estudio de los efectos del transporte y la distribución del agua en la pila y su influencia en el funcionamiento del sistema a fin de desarrollar nuevas estrategias de control. El modelo ha sido validado a partir de datos obtenidos directamente de ensayos experimentales. ABSTRACT: Water distribution in a fuel cell affects performance and durability, thus fundamental understanding of water transport mechanisms are imperative and can be strongly influenced through proper control strategies. A two-dimensional, non-isothermal, dynamic model of an open cathode, self-humidified PEMFC was developed. The model consists of three sub models using on energy, momentum and water mass balance of the system with respect to an anode, cathode channel, diffusion layers and MEA. The model is intended to be used to simulate and study the effects of water transport/distribution and its influence on the system performance to develop new water management control strategies. Essential coefficients for water transport, namely the water diffusion, EOD, and bulk specific heat capacity coefficients, have been determined experimentally. The effective water diffusion coefficient was determined to be 3.3×10m s at 30oC and increases by 3×10m s per degree until 50oC. The EOD coefficient was found to be 0.47 to 0.48 water molecules per proton at stack currents from 0.044 to 0.133Acm. The bulk specific heat capacity for one cell unit was determined to be 1260JkgK. The model has been validated by using experimental data directly obtained from laboratory tests.