3D Numerical Characterization of a Multi-Holes Injector in a Quiescent Vessel and Its Application in a Single-Cylinder Research Engine Using Ethanol

Braga, Raphael Meireles; Vaz, Marilia Gabriela Justino; Martins, Clarissa de Moraes; Hindi, Gustavo; Huebner, Rudolf

doi:10.4271/2017-36-0360

Cited by 2 publications

(3 citation statements)

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“…The data covered the main spray characteristics used in the vast majority of similar modelling studies. 14,16,19 A schematic drawing of the nozzle is presented in Figure 1 where S ϑ is the circular distance between two near holes, D i is the geometric hole diameter that for the proposed injector was 180 µm, R is the hole distance from the centre and ϑ is the angular distance between two near holes. According to Khan et al, 24 the limiting condition S θ / D i > 3 . 5 prevent the spray plumes from collapsing during the injection, mitigating the phenomena of flash boiling.…”

Section: Methodsmentioning

confidence: 99%

“…where C s2 is the fourth calibration factor of the model. The typical ranges of variation for the calibration factors are summarised in Table 2 based on the most relevant literature 15,18,19 and the Authors' previous experience. 8,10 In particular, the X range was selected considering the diameter of the holes and studying the experimental SMD for all the injection pressure tested.…”

Section: Model Description and Implementationmentioning

confidence: 99%

“…On the contrary, the combination of central flow motion and the stronger break-up produced by KH–RT model led to abnormal spray penetration and morphology. Braga et al 19 used a similar calibration methodology to predict the high-pressure injection of ethanol from a seven-hole injector using the KH–RT instability model. Four levels for each calibration factor were chosen and their effect on spray penetration characteristics analysed in comparison with experimental data.…”

Section: Introductionmentioning

confidence: 99%

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A systematic approach to calibrate spray and break-up models for the simulation of high-pressure fuel injections

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et al. 2021

International Journal of Engine Research

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A novel calibration methodology is presented to accurately predict the fundamental characteristics of high-pressure fuel sprays for Gasoline Direct Injection (GDI) applications. The model was developed within the Siemens Simcenter STAR-CD 3D CFD software environment and used the Lagrangian–Eulerian solution scheme. The simulations were carried out based on a quiescent, constant volume, computational vessel to reproduce the real spray testing environment. A combination of statistic and optimisation methods was used for spray model selection and calibration and the process was supported by a wide range of experimental data. A comparative study was conducted between the two most commonly used models for fuel atomisation: Kelvin–Helmholtz/Rayleigh–Taylor (KH–RT) and Reitz–Diwakar (RD) break-up models. The Rosin–Rammler (RR) mono-modal droplet size distribution was tuned to assign initial spray characteristics at the critical nozzle exit location. A half factorial design was used to reveal how the various model calibration factors influence the spray properties, leading to the selection of the dominant ones. Numerical simulations of the injection process were carried out based on space-filling Design of Experiment (DoE) schedules, which used the dominant factors as input variables. Statistical regression and nested optimisation procedures were then applied to define the optimal levels of the model calibration factors. The method aims to give an alternative to the widely used trial-and-error approach and unveils the correlation between calibration factors and spray characteristics. The results show the importance of the initial droplet size distribution and secondary break-up coefficients to accurately calibrate the entire spray process. RD outperformed KH–RT in terms of prediction when comparing numerical spray tip penetration and droplet size characteristics to the experimental counterparts. The calibrated spray model was able to correctly predict the spray properties over a wide range of injection pressure. The work presented in this paper is part of the APC6 DYNAMO project led by Ford Motor Company.

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