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GIUSEPPE CORDA
Dottorando Dipartimento di Ingegneria "Enzo Ferrari"
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Pubblicazioni
2023
- A MATLAB/Simulink Model of a PEM Fuel Cell System Including Ageing Phenomenon
[Relazione in Atti di Convegno]
Corda, G.; Breda, S.; D'Adamo, A.
abstract
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.
2023
- A Methodology to Design the Flow Field of PEM Fuel Cells
[Relazione in Atti di Convegno]
Corda, G.; Cucurachi, A.; Diana, M.; Fontanesi, S.; D'Adamo, A.
abstract
Proton Exchange Fuel Cells (PEMFCs) are considered one of the most prominent technologies to decarbonize the transportation sector, with emphasis on long-haul/long-range trucks, off-highway, maritime and railway. The flow field of reactants is dictated by the layout of machined channels in the bipolar plates, and several established designs (e.g., parallel channels, single/multi-pass serpentine) coexist both in research and industry. In this context, the flow behavior at cathode embodies multiple complexities, namely an accurate control of the inlet/outlet humidity for optimal membrane hydration, pressure losses, water removal at high current density, and the limitation of laminar regime. However, a robust methodology is missing to compare and quantify such aspects among the candidate designs, resulting in a variety of configurations in use with no justification of the specific choice. This contrasts with the large operational differences, especially regarding the pressure loss/stoichiometric factor trade-off and in the outlet humidity level. In this paper a simple thermodynamic model (0D) is presented to evaluate pressure losses, stoichiometric factors, channel length, and humidity level for typical flow fields. Based on distributed and concentrated pressure losses and on a water balance between the humidified air, the electrochemically produced water, and the electro-osmotic water flux, the model indicates the optimal flow field for a given active area. The methodology is validated using 3D-CFD models, assessing the predictive capability of the simplified 0D model, and it is applied to small/medium/large active area cases. The presented method introduces a model-based guideline for the design of PEMFCs flow fields, providing design indications to optimize the humid flow dynamics. The study shows the impact of flow field design on fuel cell operating conditions, providing guidelines for fuel cell engineering. In the limits of laminar flows, the parallel channel design demonstrated the lowest pressure drop (1 × 102 - 103 Pa, more than one order of magnitude lower than other designs) and the best capability of saturated outlet flows (i.e., ideal membrane hydration) for current densities in the range 0.5 - 2.0 A/cm2, hence outperforming any other serpentine-type designs for medium-to-large active areas and with the focus on high current density operation.
2023
- CFD Simulations and Potential of Nanofluids for PEM Fuel Cells Cooling
[Relazione in Atti di Convegno]
D'Adamo, A.; Corda, G.; Berni, F.; Diana, M.; Fontanesi, S.
abstract
Polymer Electrolyte Membrane Fuel Cells (PEMFCs) are undergoing a rapid development, due to the ever-growing interest towards their use to decarbonize power generation applications. In the transportation sector, a key technological challenge is their thermal management, i.e. the ability to preserve the membrane at the optimal thermal state to maximize the generated power. This corresponds to a narrow temperature range of 75-80°C, possibly uniformly distributed over the entire active surface. The achievement of such a requirement is complicated by the generation of thermal power, the limited exchange area for radiators, and the poor heat transfer performance of conventional coolants (e.g., ethylene glycol). The interconnection of thermal/fluid/electrochemical processes in PEMFCs renders heat rejection as a potential performance limiter, suggesting its maximization for power density increase. To this aim, suspensions of coolants and nanoparticles (nanofluids) have been proposed for PEMFCs cooling, although their characterization has often been limited to the superior thermal conductivity, overlooking a comprehensive understanding, and leaving a relevant research gap. In this paper, nanofluids cooling is simulated using 3D-CFD in a small laboratory scale (25 cm2) model of a hydrogen-air PEMFC with a liquid cooling circuit. The variation of the coolant fluid is studied considering flow uniformity, heat rejection, pressure losses, and power generation, ultimately leading to a high-level analysis on the trade-off between heat transfer/storage, relevant for coolant channels in PEMFCs. The study elucidates the membrane conditions and the compositional requirements for ethylene glycol and water based nanofluids to lead to a net gain in the generated power density, modelled in the range of +5/10% for high particle loading (10%) and envisaged to reach +15% for hypothesized ideal compositions. The study clarifies the role of nanofluids for PEMFC cooling and redefines their enabler contribution in the development of high power density PEMFCs, indicating guidelines for their application-designed formulation.
2023
- CFD-3D and 1D modeling of fuel cell powertrain for a hydrogen vehicle
[Relazione in Atti di Convegno]
Marra, C.; Corda, G.; D'Adamo, A.
abstract
As it is known the transport sector represents a major contributor to climate change. In particular, private transport contributes to the degradation of the air quality inside the cities or the residential areas. To address this issue, a progressive reduction of the use of fossil fuels as a primary energy source for these vehicles and the promotion of cleaner powertrain alternatives is in order. This study focuses on designing a fuel cell powertrain for a hydrogen-powered passenger car using numerical modeling. To this purpose, we initially modeled a base fuel cell and optimized its performance by using various materials for the bipolar plates and adjusting the platinum loading between the anode and cathode. Then, a preliminary design of the new powertrain has been proposed in order to achieve a nominal power of 100 kW and it has been tested on a WLTP 3b homologation cycle. Finally, we have been able to numerically estimate the behavior of the three main feeding line: hydrogen line, air line and cooling line. In conclusion, the obtained results demonstrate how numerical modelling can be successfully used in the design of complex systems such as those related to alternative energy. This work also provides a solid basis for the future development of increasingly efficient and environmentally friendly hydrogen vehicles.
2023
- Experimental assessment and predictive model of the performance of Ti-based nanofluids
[Articolo su rivista]
D'Adamo, Alessandro; Diana, Martino; Corda, Giuseppe; Cucurachi, Antonio; Cannio, Maria; Pellacani, Andrea; Romagnoli, Marcello; Stalio, Enrico; Santangelo, Paolo Emilio
abstract
The need for innovative propulsion technologies (e.g., fuel cells) in the mobility sector is posing a higher-than-ever burden on thermal management. When low operative temperature shall be ensured, dissipation of a significant amount of heat is requested, together with limited temperature variation of the coolant; mobile applications also yield limitations in terms of space available for cooling subsystems. Nanofluids have recently become one of the most promising solutions to replace conventional coolants. However, the prediction of their effectiveness in terms of heat-transfer enhancement and required pumping power still appears a challenge, being limited by the lack of a general methodology that assesses them simultaneously in various flow regimes. To this end, an experiment was developed to compare a conventional coolant (ethylene glycol/water) and a TiO2-based nanofluid (1% particle loading), focusing on heat transfer and pressure loss. The experimental dataset was used as an input for a physical model based on two independent figures of merit, aiming at an a priori evaluation of the potential simultaneous gain in heat transfer and parasitic power. The model showed conditions of combined gain specifically for the laminar flow regime, whereas turbulent flows proved inherently associated to higher pumping power; overall, criteria are presented to evaluate nanofluid performance as compared to that of conventional coolants. The model is generally applicable to the design of cooling systems and emphasizes laminar flow regime as promising in conjunction with the use of nanofluids, proposing indices for a quantitative a priori evaluation and leading to an advancement with respect to an a posteriori assessment of their performance.
2023
- Experimental measurements and CFD modelling of hydroxyapatite scaffolds in perfusion bioreactors for bone regeneration
[Articolo su rivista]
D’Adamo, Alessandro; Salerno, Elisabetta; Corda, Giuseppe; Ongaro, Claudio; Zardin, Barbara; Ruffini, Andrea; Orlandi, Giulia; Bertacchini, Jessika; Angeli, Diego
abstract
In the field of bone tissue engineering, particular interest is devoted to the development of 3D cultures to study bone cell proliferation under conditions similar to in vivo ones, e.g. by artificially producing mechanical stresses promoting a biological response (mechanotransduction). Of particular relevance in this context are the effects generated by the flow shear stress, which governs the nutrients delivery rate to the growing cells and which can be controlled in perfusion reactors. However, the introduction of 3D scaffolds complicates the direct measurement of the generated shear stress on the adhered cells inside the matrix, thus jeopardizing the potential of using multi-dimensional matrices. In this study, an anisotropic hydroxyapatite-based set of scaffolds is considered as a 3D biomimetic support for bone cells deposition and growth. Measurements of sample-specific flow resistance are carried out using a perfusion system, accompanied by a visual characterization of the material structure. From the obtained results, a subset of three samples is reproduced using 3D-Computational Fluid Dynamics (CFD) techniques and the models are validated by virtually replicating the flow resistance measurement. Once a good agreement is found, the analysis of flow-induced shear stress on the inner B-HA structure is carried out based on simulation results. Finally, a statistical analysis leads to a simplified expression to correlate the flow resistance with the entity and extensions of wall shear stress inside the scaffold. The study applies CFD to overcome the limitations of experiments, allowing for an advancement in multi-dimensional cell cultures by elucidating the flow conditions in 3D reactors.
2023
- Three-Dimensional CFD Simulation of a Proton Exchange Membrane Electrolysis Cell
[Articolo su rivista]
Corda, G.; Cucurachi, A.; Fontanesi, S.; D'Adamo, A.
abstract
The energy shift towards carbon-free solutions is creating an ever-growing engineering interest in electrolytic cells, i.e., devices to produce hydrogen from water-splitting reactions. Among the available technologies, Proton Exchange Membrane (PEM) electrolysis is the most promising candidate for coping with the intermittency of renewable energy sources, thanks to the short transient period granted by the solid thin electrolyte. The well-known principle of PEM electrolysers is still unsupported by advanced engineering practices, such as the use of multidimensional simulations able to elucidate the interacting fluid dynamics, electrochemistry, and heat transport. A methodology for PEM electrolysis simulation is therefore needed. In this study, a model for the multidimensional simulation of PEM electrolysers is presented and validated against a recent literature case. The study analyses the impact of temperature and gas phase distribution on the cell performance, providing valuable insights into the understanding of the physical phenomena occurring inside the cell at the basis of the formation rate of hydrogen and oxygen. The simulations regard two temperature levels (333 K and 353 K) and the complete polarization curve is numerically predicted, allowing the analysis of the overpotentials break-up and the multi-phase flow in the PEM cell. An in-house developed model for macro-homogeneous catalyst layers is applied to PEM electrolysis, allowing independent analysis of overpotentials, investigation into their dependency on temperature and analysis of the cathodic gas–liquid stratification. The study validates a comprehensive multi-dimensional model for PEM electrolysis, relevantly proposing a methodology for the ever-growing urgency for engineering optimization of such devices.
2022
- Methodology for PEMFC CFD Simulation Including the Effect of Porous Parts Compression
[Articolo su rivista]
Corda, G.; Fontanesi, S.; D'Adamo, A.
abstract
In this paper, a three-dimensional, multi-physics and multi-phase CFD model is presented and validated on straight single-channel configurations to analyse the influence of the channel/rib width ratio. In the first part, two cases with wide/narrow channel/rib spacing are reproduced from a literature campaign including neutron radiography (NRG) measured water distribution, which is well reproduced in simulations thanks to the novel implementation of an in-house developed macro-homogeneous catalyst layer sub-model. In the second part, the inclusion of an adapted compression model from literature allows to investigate in detail the effect that the deformation of the porous parts (diffusion media and catalyst layers) has on the cell performance, considering two levels of compression (i.e. clamping pressure). All transport properties (flow/energy/charge) are locally modified as a function of the inhomogeneous compression acted by the BPPs, e.g. influencing flow permeability and thermo/electrical conductivity. The obtained numerical results are compared against those from the undeformed geometry, highlighting a relevant operational difference and explaining it as a compression-related oxygen starvation. The study presents a comprehensive model for PEMFC simulation, including an efficient catalyst layer model and demonstrating the relevance of including the often-neglected compression effect on full-scale cell (or stack) models.
2022
- Numerical Comparison of the Performance of Four Cooling Circuit Designs for Proton Exchange Membrane Fuel Cells (PEMFCs)
[Relazione in Atti di Convegno]
Corda, G.; Fontanesi, S.; D'Adamo, A.
abstract
Polymer Electrolyte Membrane Fuel Cell (PEMFC) are
among the most promising technologies as energy
conversion devices for the transportation sector due
to their potential to eliminate, or greatly reduce, the produc-
tion of greenhouse gases. One of the current issues with this
type of technology is thermal management, which is a key
aspect in the design and optimization of PEMFC, whose main
aim is an effective and balanced heat removal, thus avoiding
thermal gradients leading to a cell lifetime reduction as well
as a decrease in the output performance. In addition, a
uniform temperature distribution contributes to the achieve-
ment of a uniform current density, as it affects the rate of the
electrochemical reaction. This is made even more challenging
due to the low operating temperature (80°C), reducing the
temperature difference for heat dissipation, and leaving a
critical role to the design and optimization of the cooling
circuit design.
In this paper, a three-dimensional and multi-physics CFD
approach is used to compare four different liquid cooling flow
fields within the bipolar plates, using a conventional cooling
fluid. Several typical cooling flow rates will be tested and
equalized among all the considered cases, in order to carry
out consistent comparisons. Numerical analyses will include
Index of Uniform Temperature (IUT), minimum and
maximum temperature gradient, coolant circuit pressure
drop, thermal power absorbed by the coolant and performance
of the cell, thus providing a detailed and comprehensive
overview of a PEMFC thermal survey. The study paves the
way for a conjugate fluid-dynamic/thermal characterization
of a full PEMFC stack, thus constituting a fundamental step
towards a CAE-based engineering of fuel cells.
2022
- Numerical Simulation of Advanced Bipolar Plates Materials for Hydrogen-Fueled PEM Fuel Cell
[Relazione in Atti di Convegno]
D'Adamo, A.; Corda, G.
abstract
Hydrogen-fueled Proton Exchange Membrane Fuel
Cells (PEMFC) are considered one of the most prom-
ising 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 allow-
able 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 combus-
tion 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 motivated
the recent research on advanced materials for these
components, aiming at simultaneous elevated electrical and
thermal conductivity, reduced contact resistance, poor oxida-
tion tendency and low density.
In this study a fundamental multi-dimensional and
multi-physics 3D-CFD analysis is carried out to evaluate the
effect on the membrane physical/electrochemical status for
different types of bipolar plates, moving from conventional
graphite to advanced materials, including coated stainless
steel. A detailed analysis is carried out on the fuel cell thermal
management, rationalizing the heat dissipation pathways and
the membrane hydration balance for the considered cases.
The study relevantly shows the effects of advanced research
on bipolar plates materials on a cell-scale, filling a knowledge
gap between the fundamental research on bulk material prop-
erties for bipolar plates and the resulting PEMFC fluid/
thermal processes, thus providing guidelines for PEMFC
engineering advancement.