bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrogen and Natural Gas in Pipeline Networks: A Comparative Energy Analysis
Authors: Cava Carmine , Pozzessere Adriano , Caravelli Alessandro , Borello Domenico 
Published: December 2024

Abstract
In this study, a Simscape model for the transmission and distribution pipeline network of natural gas, hydrogen blended into natural gas and pure hydrogen, is developed. The transmission consists of a 250 km pipelines with a diameter of 48 in and two gas compression stations. The distribution network serves six end users. Two simulations are conducted for each gas: the first maintaining equal operational pressure in the transmission pipeline, while the second ensuring equal energy content at the final users by modifying the operational pressure. A comparative energy analysis is carried out to assess the gas mass flow rate, the thermal power delivered, the mechanical power required by compressors and the pressure losses along the pipeline.
Optimizing Hybrid Electric Microcar Design: A Simulation-Based Approach to Fuel-Cell Powertrains Analysis
Authors: Bartolucci Lorenzo , Cennamo Edoardo , Cordiner Stefano , Donnini Marco , Mulone Vincenzo 
Published: December 2024

Abstract
The pressing need to reduce emissions and pollutants requires a significant diversification of mobility solutions and energy sources used to this aim. Light quadricycles with electric powertrains are increasingly recognized in research and industrial sectors as viable alternatives for achieving urban sustainable mobility solutions. Their lightweight design, compact dimensions, simplified prototyping and manufacturing processes, high efficiency, and lower emissions across the entire life cycle contribute to their growing importance.
In line with this trend, integrating a hydrogen fuel cells stack with a battery pack is a promising powertrain solution, leveraging both technologies’ strengths. However, the design and development of such hybrid systems necessitate advanced methodologies that can address the problem of significant prototyping costs and time commitments while still ensuring optimal configurations. The availability of detailed simulation tools integrated with hardware components (vehicle simulation platforms) plays a crucial role in this endeavor, enabling insights on local phenomena which otherwise would be neglected, as such the purge phase, strongly impacting on the global consumption. These test platforms encompass all the main subsystems to account for all the vehicle demands while ensuring very good reliability for the predictions of performance and allowing the validation of the components. This enables the possibility of testing the vehicle under a wide set of operating conditions (e.g., weather conditions and driving cycles) within a simulated environment, thus reducing the costs related to the component sizing issues. In this context, the work presented in this paper, develops the fuel cell stack sizing analysis of a hybrid electric microcar, proposing a methodological approach for the powertrain design process.
A detailed simulation platform is introduced for a hybrid electric microcar. The two energy sources, namely the Li-ion battery pack and the fuel cell stack, have been experimentally characterized and implemented into the model, also considering the experimental performances of the balance of plant elements as of the DC-DC converter.
A linear scale-up method is implemented on the fuel cell stack to consider different configurations, and a deep analysis of the hydrogen consumption, comprising the scale-up of the purge phase, is presented, proposing two different approaches to the problem. From a technological standpoint, different results regarding the choice of fuel cell size have been found. As an example, the role of purging and its relationship with the size of the fuel cell stack may lead to a 14 % increase in the vehicle’s estimated range with respect to the baseline. Cost analyses are then needed to reach a trade-off between the costs and the technological standpoints.
A Novel Hydrogen-Nitrogen Heat Exchanger For Aeronautical Applications
Authors: Domenico Vincenzo Di , Tamburrano Paolo , Sciatti Francesco , Distaso Elia , Foglia Mario Massimo , Amirante Riccardo 
Published: December 2024

Abstract
Renewable fuels are playing an increasingly central role in shaping today’s energy landscape, and within the aviation sector there is a remarkable drive to research and develop engines that harness the potential of these sustainable resources. Looking specifically at hydrogen, a fuel with immense promise, there is a critical need to maximize storage capacity, prompting consideration of storing it in a liquid state. However, before this stored hydrogen can be used for combustion, it must undergo an important process of vaporization. To address this challenge, this paper presents an innovative heat exchanger model. In this model, nitrogen is used as a medium to transfer heat energy to the stored hydrogen, allowing it to be converted to a gaseous state and making it easily usable in the combustion chamber. In addition, to provide a comprehensive understanding of the thermodynamic processes involved, a detailed and thorough thermodynamic model is presented that properly captures the exchange of heat flow rates. Moreover, the pipe-in-pipe architecture is adopted, and the assumed geometrical data are validated numerically.
Feasibility study and sizing of TES coupled with Metal Hydrides storage for H2 fuelled ships
Authors: Barberis Stefano , Rivarolo Massimo 
Published: December 2024

Abstract
The International Maritime Organization (IMO) established a challenging global strategy in 2023 to reduce greenhouse gas (GHG) emissions from international shipping by 70% by 2040. Achieving these targets necessitates radical actions, including the use of carbon free fuels and hybrid-alternative propulsion systems. The NEREHYDES (Novel hEat REcovery solutions on board of fuel cell equipped vessels for metal HYDridES storage optimal management) national research project aims to optimize the design and management of a hybrid system with hydrogen fuelled Proton Exchange Membrane Fuel Cells (PEMFC) and diesel Internal Combustion Engines (ICE) on board short-travel ferries for zero-emission operation in coastal and harbour areas. Hydrogen would be stored on board via metal hydrides storage (MH), allowing for the H2 storage at low pressure and close to room temperature.. The new PEMFC - MH system is designed to operate mostly in harbour, while the traditional ICE operates during navigation in open sea. In this way, Waste heat produced by the engine could be stored on board of TES to be then used to properly manage the metal hydrides discharging once in harbour to properly operate the PEMFC: once the PEMFC will be fully operative, the waste heat produced by the FC could be exploited in order to minimize TES size.
The study consists of a pre-feasibility analysis for sizing the TES on board based on above mentioned operational strategy of the integrated system (ICE-TES-MH-PEMFC) towards the minimization of the volumes. At this purpose two different type of TES (sensible heat with hot water and latent heat with identified PCM suitable to manage the MH discharge) will be compared, analysing the volume and cost needs for both of them.
The study is carried out considering the requirements of a real vessel operating in Stretto di Messina - Sicily (Italy) and its daily travelling routes, aiming to compare the sizing architectures of the integrated system via a heat transfer modelling tool developed by the Thermochemical Power Group (TPG) at the University of Genoa.
Hydrogen Valleys for Local Energy System Decarbonization: An Assessment of the Environmental and Economic Aspects
Authors: Bekele Endeshaw , Ciancio Alessandro , Massulli Axel Riccardo , Santoli Livio de 
Published: December 2024

Abstract
The necessity to address the adverse impact of global climate change has led to the widespread adoption of clean energy and the prioritization of decarbonising “hard-to-abate” sectors. This work aims to investigate the environmental and economic aspects of a Hydrogen Valley to facilitate the decarbonization of local energy systems and to integrate the hydrogen value chain across various stages from production to utilization. The southern Italian province of Taranto was selected for the case study, and the energy system is modelled in EnergyPLAN software considering the ‘business as usual’ scenario. The levelized cost of hydrogen (LCOH) is calculated, and its variation with the installation cost of the electrolyser is analysed. The result shows that the carbon emissions and total annual costs of the business-as-usual scenario are 4.098 Mt of CO2 emissions and 0.98 billion euros, respectively. The levelized cost of hydrogen is found to be 4.09 €/kg. A 71.4% reduction in capital expenditure (CAPEX) will decrease the levelized cost of hydrogen (LCOH) to 2.78 €/kg, highlighting the crucial role of cost reductions in electrolyser technologies for achieving a lower levelized cost of hydrogen.
Numerical analysis of the aspect ratio effect on mixed convection in vertical channels asymmetrically heated with nanofluids with assisting and opposing moving plate
Authors: Buonomo Bernardo , Manca Oronzio , Nardini Sergio , Sarli Gianluca 
Published: December 2024

Abstract
In this study, a numerical investigation on mixed convection in vertical channel with water-alumina (Al2O3) nanofluids due to the interaction between a buoyancy-driven flow and a moving plate-induced one in a vertical channel is performed. One of the plates that bound the channel is heated by a constant heat flux, while the other, considered adiabatic, moves with a constant velocity in the direction of the buoyancy force or in the opposite direction, with a comparison between the two options. The nanofluid is modelled using the Single-Phase Model. The thermophysical properties are assumed to be constant with temperature, and the fluid flow is considered laminar and incompressible. The governing equations are numerically solved with the finite volume method by means of the ANSYS-FLUENT code. The channel can have three different aspect ratios, ranging between 5 to 20, while the two external reservoirs allow simulating the external ambient and assigning a velocity of zero and the ambient temperature at the boundary of the reservoirs. The impacts of the different values of aspect ratio of the channel, wall heat flux, moving plate velocity, and concentration of the nanoparticles are investigated. Results in terms of temperature and velocity are provided. Finally, correlations for predicting of the average Nusselt number along the heated plate are proposed.
Estimating the minimum ignition energy of spark-ignited fuel/air mixtures: preliminary steps towards a novel modelling approach
Authors: Pretto Marco , Betta Enrico De , Giannattasio Pietro 
Published: December 2024

Abstract
In spark-ignition (SI) engines, the achievement of a fast combustion with low cycle-to-cycle variation is highly dependent on the successful initiation of a flame kernel from the spark plug. Its growth can be sped up by increasing the electrical energy supply, but at the cost of higher plug wear, whereas too little energy may result in an ignition failure. Therefore, knowledge of the minimum ignition energy (MIE) of a fuel/air mixture is of key importance to guarantee a proper combustion process at minimal cost. To model the MIE several approaches have been proposed in literature, primarily derived from the experiments conducted by Lewis and Von Elbe and their resulting theory of quenching distances. However, these approaches appear in conflict with more recent experimental outcomes, and the impact of the ignition device is neglected. This work proposes a novel approach for modelling the MIE, which is based on a flame kernel expansion model recently proposed in another paper. In this approach, the proposed model, which has general validity, is specialized to the particular case of the estimation of the MIE, supplied via an electrical breakdown. A model advancement is also included that consists in the quantification, albeit at a preliminary level, of the impact of different gap distances and spark plug quenching effects on the flame kernel development. The results are validated against literature models and experimental data for two fuels, propane and hydrogen, and multiple equivalence ratios. In contrast with the noticeable MIE overestimation of literature models, for propane the proposed approach leads to better results compared to the experiments. Instead, for hydrogen a tendency towards a MIE underestimation is observed, especially for lean mixtures. The model is also tested for SI-engine-relevant conditions, showing satisfactory overall trends. The key source of error seems related to the very complex kernel-electrode interaction, the modelling of which will be improved in future developments.
Chemical kinetics calculation of H2 Laminar Flame Speed: assessment of the performance of public available mechanisms at engine relevant conditions
Authors: Baudone Antonio Denny , Madia Manuel , Pavan Nicolò , Cordisco Ilario , Patrizi Veronica , Marini Alessandro 
Published: December 2024

Abstract
The laminar flame speed (LFS) of actual fuels is a critical property to consider when approaching the computational fluid dynamics (CFD) simulation of turbulent flame propagation in internal combustion engines. A significant gap persists between the conditions under which LFS can be measured and the engine conditions, particularly in terms of pressure and temperature, at high loads in high-specific power engines. Chemical kinetics simulations can be employed to calculate LFS at high pressures and temperatures by using mechanisms that cannot, however, be validated under such conditions due to the unavailability of experimental data. In this study, a literature review was conducted to identify measured values of H2 LFS to be compared with calculated ones through chemical kinetics simulations, using various published chemical schemes. A methodology is developed to assess the reliability of the tested mechanisms for CFD engine simulations, considering more relevant experimental data at higher pressures and temperatures, low dilution, and near-stoichiometric conditions. At low pressures and temperatures (i.e. at part-load engine conditions), all the considered chemical mechanisms yield similar results consistent with those of the Verhelst correlation. However, as the physical conditions move toward a high-load representative one, the choice of chemical scheme for LFS calculation can significantly impact the prediction of turbulent flame speed in actual engines, leading to non-negligible discrepancies.
Experimental and numerical analysis of a waste-gated turbine for automotive turbocharged engine
Authors: Cordalonga Carla , Usai Vittorio , Marelli Silvia 
Published: December 2024

Abstract
This work presents the results of an experimental campaign focused on the steady state behaviour of a waste-gated turbocharger turbine for spark ignition engine. In a first step, the turbine behaviour under different openings of the waste-gate valve is analysed through an experimental campaign performed at the test rig for components of propulsion systems of the University of Genoa.
Based on this experimental activity, a specific numerical model is developed to study the interaction between the rotor channel and the waste-gate valve.
A 1D schematization of the experimental test rig is implemented within the commercial GT-Power code, including the turbine, the waste-gate valve, and the upstream and downstream circuits. In the turbine schematization, the “wheel-map”, estimated by means of the 1D software, is utilized.
A preliminary tuning is carried out based on the turbine characteristic map measured with the waste-gate valve in the fully closed position. Then, the influence of various positions of the by-pass valve on the definition of turbine characteristic curves is investigated under steady flow condition.
A refined model of the waste-gate system reveals to be necessary to correctly reproduce the swallowing capacity of the by-pass port. The waste-gate model is tuned against the experimental findings for a completely closed turbine wheel and various settings of the waste-gate valve.
Finally, once the 1D models of the turbine and of the waste-gate system are independently tuned, their behaviour under parallel flow is analysed. The proposed numerical and experimental results demonstrate the mutual interaction of the two components. In addition, it is highlighted that the turbine and the waste-gate circuit cannot be considered as two systems working in parallel under the same pressure ratio, as usually assumed in 1D codes.
Experimental analysis of the performance of a turbocharger compressor under pulsating flow condition
Authors: Nannetti Federico , Usai Vittorio , Cordalonga Carla , Marelli Silvia 
Published: December 2024

Abstract
To achieve zero CO2 emissions in the transport sector, hydrogen internal combustion engines (H2 ICE) appear to be one of the most promising solutions, particularly for heavy-duty applications. Achieving low NOx emissions requires ultra-lean combustion, which necessitates the use of high air-to-fuel ratios. To obtain this result, suitable boosting systems are required. This study aims to understand the behaviour of a turbocharger compressor. The performance of the compressor is strongly influenced by the unsteady flow generated by the motion of the engine’s intake valves. Achieving a more accurate prediction of engine performance in simulation models requires a deeper understanding of the pulsating flow performance. This understanding can be obtained through measurements conducted in specialized test facilities using appropriate measuring equipment. All the analyses reported in this paper take place at the Test Bench for Components of Propulsion System of the Department of Mechanical, Energy, Management and Transportation Engineering (DIME) of the University of Genoa. Following a short description of the instrumentations adopted, the actual experimental layout, the results obtained from the investigations on the compressor, operating under both steady and unsteady flow conditions, are outlined. The tested turbocharger compressor is coupled to the automotive engine intake circuit, where pulsating flow is generated by a motor-driven cylinder head. Different levels of turbocharger and camshaft rotational speeds are analyzed. For each operating condition, the unsteady performance of the compressor is assessed by measuring several instantaneous parameters, including inlet and outlet static pressure, mass flow rate, and turbocharger rotational speed. Furthermore, the effects of the intake circuit and its interaction with the compressor is deeply analyzed. In particular, the energy content associated with the pulses generated by the intake valves motion is taken into account, considering the hysteresis loops on the compressor map.
Impact of Ozone Addition to Gasoline Surrogates Combustion in Spark Ignition Engine
Authors: Anaclerio Fabio , Camporeale Sergio Mario , Magi Vinicio , Fornarelli Francesco 
Published: December 2024

Abstract
Based on the experimental results, a 3-D Computational Fluid Dynamics investigation is carried out to evaluate the influence of ozone on the combustion process in spark ignition engine fueled with gasoline/air mixtures. Ozone (O3) is a chemically reactive species capable of improving the laminar flame speed, reducing the ignition delay time, and stabilizing combustion variability. With the aim of proposing a 3-D numerical model to simulate combustion of fuel mixtures under ultra-lean conditions, two numerical correlations are proposed to reproduce the chemical properties of gasoline/air/ozone mixtures in terms of laminar flame speed. A chemical kinetic mechanism for Toluene Reference Fuel oxidation (iso-octane, n-heptane, toluene, 63/20/17% by mol.) modified with an ozone sub-mechanism is used to perform several 1-D numerical simulations. The laminar flame speed correlation estimates an enhancement of 3.4% at 600 K and 10 bar under ultra-lean condition (ϕ = 0.6). For the 3-D numerical simulations, the G-Equation model is used to reproduce the premixed combustion process in internal combustion engines. The results suggest that the numerical correlations can predict the combustion properties of gasoline/air mixtures without and with ozone addition. The presence of ozone traduces in a higher laminar flame speed, leading to an increase in the in-cylinder pressure peak and the rate of fuel consumption. Furthermore, the numerical analysis reveals that the greatest improvement is observed for fluid regions within the cylinder characterized by low turbulent flame speed.
Two-phase flow pattern recognition inside tubes by a novel diagnostic technique
Authors: Amoresano A. , Barrasso M. , Langella G. , Quaremba G. , Dedes M. , Iodice P. 
Published: December 2024

Abstract
A two-phase (liquid-gas) flow represents a highly complex regime influenced by factors such as the mass flow rate of each phase, fluid dynamic and thermal conditions, viscosity, density, and surface tension. The presence and distribution of bubbles within the liquid phase significantly impact heat transfer mechanisms and the performance of components like pumps, valves, and nozzles. This study aims to develop and validate a method for identifying the flow regime within a horizontal duct and accurately quantifying flow parameters. The authors have developed a sensing methodology and instrumentation capable of detecting and analysing the vibrational modes of ducts. This approach enables the identification of flow patterns and serves as a sensor for two-phase flow in Direct Steam Generation (hereafter DSG) solar fields. In the experimental by regulating the pump’s rotational speed, inlet gas pressure, and volumetric flow rate, various two-phase flow configurations were replicated. The flow patterns were characterized using independent statistical indices such as crest factors, shape factors, medians, and modes, to define an objective function capable of describing bubble cluster behaviour on a phase diagram (Poincare map), in which more than 76 % of cases were correctly processed. This analysis employs Poincare’s topological theory and the “within-between approach” in multivariate analysis.