A zonal secondary break-up model for 3D-CFD simulations of GDI sprays

Berni, Fabio; Sparacino, Simone; Riccardi, Marco; Cavicchi, Andrea; Postrioti, Lucio; Borghi, Massimo; Fontanesi, Stefano

doi:10.1016/j.fuel.2021.122064

Cited by 13 publications

(6 citation statements)

References 73 publications

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“…The primary droplets so formed can undergo further atomization in the secondary breakup region, as well as collision/coalescence phenomena. (Jenny et al 2012;Banerjee and Rutland 2015;Linne 2013;Bravo and Kweon 2014;Berni et al 2022). This region is characterized by strong droplet-gas fluid dynamic interactions, which promote air/fuel mixing and the onset and growth of turbulent structures in the gas phase (Mitroglou et al 2007;Ghasemi et al 2014;Lee and Park 2014;Li et al 2022).…”

Section: D Tomographic Reconstructionmentioning

confidence: 99%

Shadowgraph Tomography of a High Pressure GDI Spray

Lazzaro,

Alfuso,

Ianniello

2024

Preprint

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An isooctane spray from a high-pressure multi-hole GDI injector (Bosch HDEV6) was characterized by means of optical extinction tomography, relying on parallel illumination by a focused-shadowgraph setup. The tests were carried out in air at ambient conditions at an injection pressure of 300 bar. Extinction images of the spray were acquired over a 180-degree angular range in 1-degree increments. The critical issues of optical extinction tomography of sprays, related to the strong light extinction by the dense liquid core of fuel jets, were addressed. To mitigate artifacts arising from the reconstruction process, the extinction data were subjected to spatially-variant filtering steps of both the raw and post-log data, before being analytically inverted through the inverse Radon transform. This made it possible to process extinction data for very large optical depths. A nearly complete three-dimensional reconstruction of the spray was obtained, providing significant details of the spray morphology and the internal structure of the jets throughout the spray development. The different phases of the atomization process from the near-field to far-field regions of the spray were observed.

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Section: D Tomographic Reconstructionmentioning

confidence: 99%

Shadowgraph Tomography of a High Pressure GDI Spray

Lazzaro,

Alfuso,

Ianniello

2024

Preprint

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“…Fuel is single-component and the properties are user-coded and provided by the fuel supplier. The syringe-like effect described in Postrioti et al 62 is taken into account to improve the numerical outcomes during the first stage of the injection. As a consequence of this effect, the initial mass flow rates are characterized by non-zero values.…”

Section: Numerical Set-upmentioning

confidence: 99%

Modeling of gaseous emissions and soot in 3D-CFD in-cylinder simulations of spark-ignition engines: A methodology to correlate numerical results and experimental data

Berni

Pessina

Paltrinieri

et al. 2022

International Journal of Engine Research

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In order to reduce development costs and time-to market, 1D and 3D CFD tools can support engine design providing reliable estimations of the tailpipe emissions. In particular, 3D-CFD in-cylinder simulations can evaluate formation of both soot and gaseous pollutants inside the combustion chamber. The main issue in such kind of simulations is the validation against experimental findings. In fact, the complexity of the emission measurements does not allow a straightforward one-to-one comparison between numerical and experimental results. Therefore the present paper aims at providing, on the one hand, a robust numerical framework for both gaseous and solid emissions, on the other hand a dedicated post-processing for a fair comparison between simulations and experiments. From a numerical standpoint, a simplified approach is dedicated to gaseous emissions, while a more detailed one is reserved to soot modeling. The latter is based on the Sectional Method, whose reaction rates are tabulated following 0D chemical kinetic simulations of a purposely designed surrogate in a constant pressure reactor. Simulations and experiments proposed in the present analysis are referred to a high-performance turbocharged direct-injection spark-ignition engine operated at part-load and low rpms. On equal performance, revving speed and mean mixture quality, different injection timings are investigated. The developed numerical approach and post-processing ensure a good agreement between simulations and experiments.

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“…Large angle spray is favored and is formed by short spray core and break-up length. Long break-up length, on the other hand, is avoided as it causes a narrow unsteady spray [68][69][70][71]. Moreover, due to its longer spray characteristics, the fuel might stick to the inner side of the chamber when it is impinged to the in-cylinder wall, leading to high hydrocarbon and particulate matter emissions.…”

Section: Spray Atomizationmentioning

confidence: 99%

Diesel Spray: Development of Spray in Diesel Engine

Djamari

Idris²,

Paristiawan³

et al. 2022

Sustainability

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Research and development in the internal combustion engine (ICE) has been growing progressively. Issues such as air pollution, fuel cost, and market competitiveness have driven the automotive industry to develop and manufacture automobiles that meet new regulation and customers’ needs. The diesel engine has some advantages over the gasoline or spark ignition engine, including higher engine efficiency, greater power output, as well as reliability. Since the early stage of the diesel engine’s development phase, the quest to obtain better atomization, proper fuel supply, and accurate timing control, have triggered numerous innovations. In the last two decades, owing to the development of optical technology, the visualization of spray atomization has been made possible using visual diagnostics techniques. This advancement has greatly improved research in spray evolution. Yet, a more comprehensive understanding related to these aspects has not yet been agreed upon. Diesel spray, in particular, is considered a complicated phenomenon to observe because of its high-speed, high pressure, as well as its high temperature working condition. Nevertheless, several mechanisms have been successfully explained using fundamental studies, providing several suggestions in the area, such as liquid atomization and two-phase spray flow. There are still many aspects that have not yet been agreed upon. This paper comprehensively reviews the current status of theoretical diesel spray and modelling, including some important numerical and experimental aspects.

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A zonal secondary break-up model for 3D-CFD simulations of GDI sprays

Cited by 13 publications

References 73 publications

Shadowgraph Tomography of a High Pressure GDI Spray

Shadowgraph Tomography of a High Pressure GDI Spray

Modeling of gaseous emissions and soot in 3D-CFD in-cylinder simulations of spark-ignition engines: A methodology to correlate numerical results and experimental data

Diesel Spray: Development of Spray in Diesel Engine

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