Persona: Urquía Moraleda, Alfonso
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Urquía Moraleda
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Alfonso
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Publicación FuelCell Lib - A Modelica Library for Modeling of Fuel Cells(Modelica, Gerhard Schmitz (editor), 2005-03-07) Guinea Díaz, Domingo; Sebastián, Dormido; Rubio González, Miguel Ángel; Urquía Moraleda, Alfonso; María González, José LeandroPublicación Diagnosis of PEM Fuel Cells through Current Interruption(Elsevier, 2007-01-01) Sebastián, Dormido; Rubio González, Miguel Ángel; Urquía Moraleda, AlfonsoPublicación GAPILib - A Modelica Library for Model Parameter Identifica Using Genetic Algorithms(The Modelica Association, 2006-09-04) Guinea Díaz, Domingo; Sebastián, Dormido; Rubio González, Miguel Ángel; Urquía Moraleda, Alfonso; María González, José LeandroPublicación Simulation practice with Modelica(Universidad Nacional de Educación a Distancia (España). Editorial, 2018-10-01) Urquía Moraleda, Alfonso; Martín Villalba, Carla; Rubio González, Miguel Ángel; Sanz Prat, VíctorinoThis activity book is aimed to provide an introduction to the simulation practice in Engineering using Modelica. To this end, we propose a series of thirteen independent hands-on assignments of increasing complexity. Each assignment contains the description of a system and a mathematical model of the system's behavior. The proposed task often consists in describing this mathematical model in the Modelica language and simulate it. In some assignments, the system's behavior is described as an atomic model, without internal structure. Some other assignments ask to design and implement a model library, and to compose the system model by instantiating and connecting components from this model library. Before start working with this activity book, it is advisable to read its companion theory book: a free e-book entitled "Modeling and simulation in Engineering using Modelica", written by Alfonso Urquía and Carla Martín, and published by Editorial UNED in 2018Publicación Performance uniformity analysis in polymer electrolyte fuel cell using long-term dynamic simulation(ELSEVIER, 2024) Culubret, Sergi; Rubio González, Miguel Ángel; Sanchez, D.G.; Urquía Moraleda, Alfonso; https://orcid.org/0000-0002-4245-8103The temporal stability and spatial homogeneity of current density are key factors in Polymer Electrolyte Fuel Cell (PEFC) performance and durability. Temporal and spatial variations of relative humidity, fuel concentration, and water droplets in the channels are the principal causes of non-homogeneous current density. A dynamic pseudo-3D model was previously proposed by the authors and has been extended and improved to perform the long-term and intensive simulations of PEFC with low computational cost, which allows to study of the performances homogeneity with different experimental configurations and flow field topologies. The model considers important phenomena in the homogeneity analysis, such as gases and liquid water movement in diffusion layers and flow field, electrochemical reactions, and others. Model validation has been performed using experimental data obtained from a 25 cell with a single serpentine, which has allowed studying the model transient response and spatial representation. The simulations have been used to study the homogeneity and stability of 36 setups of PEFC, varying the rib/channel width ratio, the stoichiometric ratio, and the number of parallel serpentine channels. The results show the importance of a properly flow field design to control gas flow, remove the channels’ liquid water, and keep a homogeneous feeding. The study evaluated a set of channel configurations that show the improved temporal voltage stability and current density spatial homogeneity. The results show the impact of channel gas speed and ratio channel/rib width in liquid droplets removal and the proper fuel spatial distribution; and how configurations with a lesser number of channels in serpentine design require a lower stoichiometric ratio to perform better temporal and spatial uniformity. In the case of the cell configurations simulated, the optimum design was achieved using between 5 and 7 parallel serpentine channels and a channel/rib ratio 3/5.