Large Eddy Simulation  as an Effective Tool for  GDI Nozzle Development

Shi, Junmei; Santos, Eduardo Gomez; Hoffmann, Guy; Dober, Gavin

doi:10.1007/s38313-018-0089-2

Cited by 8 publications

(4 citation statements)

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“…These simulations showed complex vapor structures formed due to the sudden flow blockage caused by the needle closing, even for a condition and nozzle geometry that usually does not exhibit cavitation. The strong correlation between internal nozzle flow and primary spray atomization was shown by various authors in [29,30,31,32]. The location of cavitating vortices inside the nozzle was shown to affect the instantaneous spray pattern.…”

Section: Introductionmentioning

confidence: 80%

A numerical study on the effect of cavitation erosion in a diesel injector

Cristofaro

Edelbauer

Koukouvinis

et al. 2020

Applied Mathematical Modelling

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The consequences of geometry alterations in a Diesel injector caused by cavitation erosion are investigated with numerical simulations. The differences in the results between the nominal design geometry and the eroded one are analyzed for the internal injector flow and spray formation. The flow in the injector is modeled with a 3-phase Eulerian approach using a compressible pressure-based multiphase flow solver. Cavitation is simulated with a non-equilibrium mass transfer rate model based on the simplified form of the Rayleigh-Plesset equation. Slip velocity between the liquid-vapor mixture and the air is included in the model by solving two separate momentum conservation equations. The eroded injector is found to result to a loss in the rate of injection but also lower cavitation volume fraction inside the nozzle. The injected sprays are then simulated with a Lagrangian method considering as initial conditions the predicted flow characteristics at the exit of the nozzle. The obtained results show wider spray dispersion for the eroded injector and shorter spray tip penetration.

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Section: Introductionmentioning

confidence: 80%

A numerical study on the effect of cavitation erosion in a diesel injector

Cristofaro

Edelbauer

Koukouvinis

et al. 2020

Applied Mathematical Modelling

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“…The development and evolution of turbulent vortex structures within GDI nozzles have a significant impact on the characteristics of spray discharge and atomization. [29][30][31] Therefore, under different cavitation number conditions, the Q-criterion is employed to extract the three-dimensional turbulent vortex structures within the nozzle. 32 The primary objective of the Q-criterion is to identify vortical structures within a fluid.…”

Section: Resultsmentioning

confidence: 99%

A comprehensive investigation on the internal flow and outflow characteristics of GDI elliptical divergent nozzles

Yu,

Yin,

Chen

et al. 2024

International Journal of Engine Research

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The substantial demand for enhanced combustion efficiency and achieving near-zero emissions in GDI engines has spurred the introduction of a novel approach employing elliptical divergent nozzle spray technology. This innovative method, which marries the elliptical shape with a divergent nozzle, not only elevates downstream atomization quality but also mitigates nozzle tip wetting. Nevertheless, there exists a dearth of documented research regarding the internal flow and outflow characteristics related to the atomization potential of elliptical divergent nozzles. Numerical investigations have been carried out to scrutinize alterations in the three-dimensional cavitation morphology, the dispersion of turbulent vortex structures, and the nozzle exit flow parameters across a range of cavitation number conditions for both circular and elliptical divergent nozzles. The research findings demonstrate that the cavitation intensity of the elliptical divergent nozzle consistently surpasses that of the circular divergent nozzle. Also, the elliptical divergent nozzle consistently exhibits a greater number of turbulent vortex structures compared to the circular divergent nozzle across all cavitation number conditions. Additionally, as the cavitation number decreases, the difference in turbulence vorticity magnitude between the exits of the circular and elliptical divergent nozzles gradually increases. Furthermore, the elliptical diverging orifices are more susceptible to cavitation compared to their circular counterparts. The elliptical divergent nozzle outperforms the circular nozzle with a substantial 24.6% increase in exit velocity, especially at a cavitation number of 1.016.

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“…Where p is the far field pressure, p sat is the vapour saturation pressure, ρ L the liquid density, R 0 is the initial bubble radius and R is the bubble radius The LES model setting is adapted from the basis of the previous studies on Diesel injection and primary breakup [81,82,83,84,29] and Gasoline [62,85] injection and primary breakup simulations. In order to choose the appropriate filter/mesh size for the LES, the Taylor micro-scales (λ g ) is used entrance.…”

Section: Cavitation Modelmentioning

confidence: 99%