Numerical characterization of hydrogen under-expanded jets with a focus on Internal Combustion Engines applications

Anaclerio, Giuseppe; Capurso, Tommaso; Torresi, Marco; Camporeale, Sergio Mario

doi:10.1177/14680874221148789

Cited by 5 publications

(5 citation statements)

References 51 publications

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“…The same conclusion has been drawn by the authors for a 10 bar injection in a previous work (see Anaclerio et al. 2023) and, thus, the Redlich–Kwong EoS has been here adopted. The Redlich–Kwong EoS is one of the cubic EoS available in ANSYS Fluent ® , whose general form is where , , , and are parameters related to the fluid critical pressure and critical temperature (, ), to the acentric factor and specific volume .…”

Section: Numerical Model and Validationsupporting

confidence: 54%

“…Indeed, as previously verified by the authors (see Anaclerio et al. 2023), the characteristic variation of the NPR during the injection in ICE applications is too small to produce hysteretic effects. Therefore, features of the shock system can be analysed by means of a steady computation.…”

Section: Numerical Model and Validationsupporting

confidence: 54%

“…When comparing the ideal-gas model with the real-gas models for a high pressure injection (750 bar), Bonelli observed a higher intensity of the Mach disk shock when using the real-gas models. The same conclusion has been drawn by the authors for a 10 bar injection in a previous work (see Anaclerio et al 2023) and, thus, the Redlich-Kwong EoS has been here adopted. The Redlich-Kwong EoS is one of the cubic EoS available in ANSYS Fluent ® , whose general form is…”

Section: Numerical Model and Validationmentioning

confidence: 52%

“…A mean cell size of 50 µm has been applied in the near-field zone of the jet, where intense gas-dynamic phenomena are expected to occur. Externally to the near-field zone, an average cell size of 100 µm has been deemed sufficient to effectively capture the mixing layer of the jet, responsible for the diffusion of the H 2 into the ambient fluid (see Anaclerio et al 2023). The general physics behaviour of the flow is described by the following mass, momentum and energy equations:…”

Section: Numerical Model and Validationmentioning

confidence: 99%

“…Externally to the near-field zone, an average cell size of 100 m has been deemed sufficient to effectively capture the mixing layer of the jet, responsible for the diffusion of the H into the ambient fluid (see Anaclerio et al. 2023). The general physics behaviour of the flow is described by the following mass, momentum and energy equations: Here is the local flow density, the velocity vector, the static pressure, the deviatoric stress tensor, the mass forces vector, the internal energy, the enthalpy, the thermal conductivity, the temperature, the enthalpy of the th species and the diffusion flux of the th species (see (3.5)).…”

Section: Numerical Model and Validationmentioning

confidence: 99%

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Gas-dynamic and mixing analysis of under-expanded hydrogen jets: effect of the cross section shape

Anaclerio,

Capurso,

Torresi

2023

J. Fluid Mech.

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Green hydrogen is expected to have a key role in the transition towards a carbon-neutral society, particularly in the transportation sector. Exploration of novel solutions for the direct injection of hydrogen in internal combustion engines (ICEs) is a main topic for both academia and industry. Here, the authors explore the gas-dynamic and mixing features of hydrogen under-expanded jets exiting from non-axisymmetric cross-sections, with the aim to provide guidelines for designing novel generations of ICE hydrogen injectors. Triangular and star shapes have been compared with elliptical and rectangular sections with different aspect ratios. Differences in the shock wave systems are reported, and explanations of the gas-dynamic mechanisms developed by each section are proposed. Non-uniformity in the radial expansion of the jet boundary has been noticed in all of the non-axisymmetric sections, leading to an axis switching of the jet in some cases. Differences in the radial mixing and axial jet penetration have been reported too, and a robust correlation with the vorticity distribution along the jet boundary has been observed.

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Section: Numerical Model and Validationsupporting

confidence: 54%

Section: Numerical Model and Validationsupporting

confidence: 54%

Section: Numerical Model and Validationmentioning

confidence: 52%

Section: Numerical Model and Validationmentioning

confidence: 99%

Section: Numerical Model and Validationmentioning

confidence: 99%

See 3 more Smart Citations

Gas-dynamic and mixing analysis of under-expanded hydrogen jets: effect of the cross section shape

Anaclerio,

Capurso,

Torresi

2023

J. Fluid Mech.

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A Fast and Reliable CFD Approach to Design Hydrogen SI Engines for Industrial Applications

Ramognino¹,

Sforza²,

Cerri³

et al. 2023

SAE Technical Paper Series

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<div class="section abstract"><div class="htmlview paragraph">SI engines fueled with hydrogen represent a promising powertrain solution to meet the ambitious target of carbon-free emissions at the tailpipe. Therefore, fast and reliable numerical tools can significantly support the automotive industry in the optimization of such technology. In this work, a 1D-3D methodology is presented to simulate in detail the combustion process with minimal computational effort. First, a 1D analysis of the complete engine cycle is carried out on the user-defined powertrain configuration. The purpose is to achieve reliable boundary conditions for the combustion chamber, based on realistic engine parameters. Then, a 3D simulation of the power-cycle is performed to mimic the combustion process. The flow velocity and turbulence distributions are initialized without the need of simulating the gas exchange process, according to a validated technique. However, coupled 1D-3D simulations of the engine scavenging can be carried out as well to increase the accuracy of the predicted intake valve closing (IVC) flow fields. The proposed methodology was validated against experimental measurements from a pent-roof single-cylinder spark-ignition (SI) engine, in which different values of hydrogen-air dilution were investigated. The achieved results were able to capture the measured pressure and heat release trends, demonstrating the industrial applicability of the presented methodology.</div></div>

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CFD Modelling of Hydrogen-Fueled SI Engines for Light-Duty Applications

Ramognino,

Sforza,

D'Errico

et al. 2023

SAE Technical Paper Series

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<div class="section abstract"><div class="htmlview paragraph">The employment of hydrogen as energy carrier for transportation sector represents a significant challenge for powertrains. Spark-ignition (SI) engines are feasible and low-cost devices to convert the hydrogen chemical energy into mechanical work. However, significant efforts are needed to successfully retrofit the available configurations. The computational fluid dynamics (CFD) modelling represents a useful tool to support experiments, clarifying the impact of the engine characteristics on both the mixture preparation and the combustion development. In this work, a CFD investigation is carried out on typical light-duty SI engine configurations, exploring the two main strategies of hydrogen addition: port fuel injection (PFI) and direct injection (DI). The purpose is to assess the behaviour of widely-used numerical models and methodologies when hydrogen is employed instead of traditional carbon-based fuels. First, the DI process is investigated on a research pent-roof SI engine, in which hydrogen is introduced by a single-hole injector. Numerical simulations are carried out to understand the behaviour of two turbulence models and two mesh resolutions on the prediction of the hydrogen stratification, when a non-oriented hexahedral-dominant mesh is employed with layer addition-removal for the piston motion. Results show how the experimental jet penetration is properly predicted by both selected turbulence models, while high mesh resolutions in the injection region allow to capture the shock-waves dynamics of the under-expanded jet but they have negligible effects on the global mixture stratification. Then, the PFI operation is analyzed on a pent-roof single-cylinder SI engine under highly diluted hydrogenair mixtures. Experimental measurements are used to assess the impact of both the laminar flame speed and the flame-wall interaction modeling, with no fuel stratification. Results clarified that in presence of ultra-lean conditions the correlations for the laminar flame speed prediction are more restrictive than the tabulation approach, while higher mesh refinements at walls improve the heat losses prediction.</div></div>

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Numerical characterization of hydrogen under-expanded jets with a focus on Internal Combustion Engines applications

Cited by 5 publications

References 51 publications

Gas-dynamic and mixing analysis of under-expanded hydrogen jets: effect of the cross section shape

Gas-dynamic and mixing analysis of under-expanded hydrogen jets: effect of the cross section shape

A Fast and Reliable CFD Approach to Design Hydrogen SI Engines for Industrial Applications

CFD Modelling of Hydrogen-Fueled SI Engines for Light-Duty Applications

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