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Hydrogen-fueled Proton Exchange Membrane Fuel Cells (PEMFC) are considered one of the most promising technologies for a fully sustainable power generation in the transportation sector, thanks to the direct conversion of chemical-electrical energy, the absence of harmful emissions, the optimal power density, and the allowable long-distance driving range. A current technological issue preventing their large-scale industrialization is the thermal management of PEMFC stacks, due to the absence of the heat removal action operated by exhaust gases in internal combustion engines, the low-temperature generated heat and the limited exchange areas in mobile applications. A relevant role in heat dissipation is played by bipolar plates, being the components with the largest volume occupation and greatly contributing to the PEMFC weight and cost.

This paper presents a numerical model of a Polymer Electrolyte Membrane Fuel Cell (PEMFC) system reproducing an automotive-type powertrain. The 0D model is developed in MATLAB/Simulink environment, and it incorporates all the main auxiliary components (air and hydrogen supply line, cooling circuit) as well as the PEMFC stack unit. The model includes an ageing model to estimate the PEMFC stack degradation over time, resulting in progressive efficiency loss as well as in increased auxiliary power and thermal dissipation demand. The presented model enables the estimation of both PEMFC duration and of the time-varying request of heat rejection, facilitating the selection of auxiliaries to optimize the lifelong performance. The model constitutes the backbone for the design and optimization of PEMFC systems for automotive applications, and the integration with a degradation model provides a comprehensive research tool to estimate the long-term performance and lifetime of PEMFC system.

The paper presents a combined experimental and numerical activity carried out to improve the accuracy of conjugate heat transfer CFD simulations of a high-performance S.I. engine water cooling jacket. Due to the complexity of the computational domain, which covers both the coolant jacket and the surrounding metal cast (both head and block), particular care is required in order to find a tradeoff between the accuracy and the cost-effectiveness of the numerical procedure. In view of the presence of many complex physical phenomena, the contribution of some relevant CFD parameters and sub-models is separately evaluated and discussed. Among the formers, the extent of the computational domain, the choice of a proper set of boundary conditions and the detailed representation of the physical properties of the involved materials are separately considered.