Analysis of diesel spray dynamics using a compressible Eulerian/VOF/LES model and microscopic shadowgraphy

Ghiji, Mohammadmahdi; Goldsworthy, Laurie; Brandner, PA; Garaniya, Vikram; Hield, Peter

doi:10.1016/j.fuel.2016.10.041

Cited by 61 publications

(25 citation statements)

References 59 publications

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“…Surface irregularities, which manifest themselves as opaque regions of the spray, are present within even a single nozzle diameter of the injector exit. Other recent visible light images of diesel sprays [13,40,41] show similar results. The rapid initiation of surface irregularities will rapidly increase the liquid-gas surface area even in close proximity to the nozzle, leading to a rapid decrease in the SMD measured with USAXS.…”

Section: Mpa N-dodecane Fuelsupporting

confidence: 78%

“…While recent work has used high-resolution LES methods to simulate diesel sprays [13], the computational expense of such methods is prohibitive for practical engine simulations; phenomenological methods predominate in these applications. While several phenomenological 4 models have been proposed to calculate droplet size in diesel sprays, one of the most commonlyused models is based on the growth of Kelvin-Helmholtz and Rayleigh-Taylor waves on the liquid exiting the injector [14][15][16], and is commonly termed the KH-RT model.…”

Section: Introductionmentioning

confidence: 99%

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Measurements of droplet size in shear-driven atomization using ultra-small angle x-ray scattering

Kastengren

Ilavský

Viera

et al. 2017

International Journal of Multiphase Flow

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Measurements of droplet size in optically-thick, non-evaporating, shear-driven sprays have been made using ultra-small angle x-ray scattering (USAXS). The sprays are produced by orifice-type nozzles coupled to diesel injectors, with measurements conducted from 1-24 mm from the orifice, spanning from the optically-dense near-nozzle region to more dilute regions where optical diagnostics are feasible. The influence of nozzle diameter, liquid injection pressure, and ambient density were examined. The USAXS measurements reveal few if any nanoscale droplets, in conflict with a popular computational model of diesel spray breakup. The average droplet diameter rapidly decreases with downstream distance from the nozzle until a plateau value is reached, after which only small changes are seen in droplet diameter. This plateau droplet size is consistent with the droplets being small enough to be stable with respect to further breakup. Liquid injection pressure and nozzle diameter have the biggest impact on droplet size, while ambient density has a smaller effect.

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Section: Mpa N-dodecane Fuelsupporting

confidence: 78%

Section: Introductionmentioning

confidence: 99%

Measurements of droplet size in shear-driven atomization using ultra-small angle x-ray scattering

Kastengren

Ilavský

Viera

et al. 2017

International Journal of Multiphase Flow

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“…Kinematic viscosity and thermal and mass diffusivities are taken to be all equal and given by Sutherland's formula. The subgrid terms τ sgs ji , q sgs j , and j sgs α,j are closed with the one-equation-eddy model [34] (implementation details are given elsewhere [35]), and with the use of turbulent Prandtl and Schmidt numbers equal to one. The averaged chemical source termsS H andS α are closed with the partially-stirred-reactor (PaSR) model.…”

Section: Introductionmentioning

confidence: 99%

“…Verification of these numerics is provided 90 elsewhere [37-40]. Finally, note that OpenFOAM solvers or earlier versions have been observed to 91reproduce satisfactory results in a large variety of combustion problems[15,35,[41][42][43][44][45][46][47].…”

mentioning

confidence: 99%

Numerical Simulations of Combustion Instabilities in a Combustor with an Augmentor-Like Geometry

Gonzalez-Juez

2019

Aerospace

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With the goal of assessing the capability of Computational Fluid Dynamics (CFD) to simulate combustion instabilities, the present work considers a premixed, bluff-body-stabilized combustor with well-defined inlet and outlet boundary conditions. The present simulations produce flow behaviors in good qualitative agreement with experimental observations. Notably, the flame flapping and standing acoustic waves seen in the experiments are reproduced by the simulations. Moreover, present predictions for the dominant instability frequency have an error of 7% and those of the rmspressure fluctuations show an error of 16%. In addition, an analysis of simulation results for the limit cycle complements previous experimental analyses by supporting the presence of an active frequency-locking mechanism.

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“…The implications of in-nozzle phenomena at the early beginning and after the end of injection have been related to pollutant emission and to deposit formation within the holes. In such a scenario, where low lifts and short injection shots are usual, some recent contributions have concerned the phenomenology of the very early phases of injection [3], of the primary atomization of the liquid [4] and of the phases in which fuel is trapped in the holes and in the sac at the beginning and at the end of injection [5].…”

Section: Introductionmentioning

confidence: 99%

On the Link between Diesel Spray Asymmetry and Off-Axis Needle Displacement

et al. 2017

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Abstract:Cutting edge experiments and thorough investigations have pointed out that radial components affect the needle lift of diesel nozzles. So far, the effects of such needle "off-axis" have been investigated within the nozzle and immediately downstream from the hole outlet. Here, the focus has been extended to the spray ambient, far outside a multi-hole VCO (Valve Covered Orifice) nozzle. A reference off-axis configuration of the needle has been defined and used to investigate its effects on the spray, in terms of hole-to-hole differences. Indeed, the spray alterations due to the needle position have been addressed for those factors, such as the velocity-coefficient C V and the area-coefficient C A , able to describe the nozzle flow behavior under needle off-axis. The investigation has been based on 3D-CFD (three-dimensional computational fluid dynamics) campaigns. The modeling of diesel nozzle flow has been interfaced to the Eulerian-Eulerian near-nozzle spray simulation, initializing the break-up model on the basis of the transient flow conditions at each hole outlet section. The dense spray simulation has been on-line coupled to the Eulerian-Lagrangian modeling of the dilute spray region. Quantitative results on each fuel spray have been provided (in terms of penetration and Sauter Mean Diameter). The range of variability within the spray characteristics are expected to vary has been found and reported, providing reference information for lumped parameter models and other related investigations.

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Analysis of diesel spray dynamics using a compressible Eulerian/VOF/LES model and microscopic shadowgraphy

Cited by 61 publications

References 59 publications

Measurements of droplet size in shear-driven atomization using ultra-small angle x-ray scattering

Measurements of droplet size in shear-driven atomization using ultra-small angle x-ray scattering

Numerical Simulations of Combustion Instabilities in a Combustor with an Augmentor-Like Geometry

On the Link between Diesel Spray Asymmetry and Off-Axis Needle Displacement

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