Transient needle motion of an outwardly opening GDI injector and its effects on initial spray formation

Komada, Keisuke; Moon, Seoksu

doi:10.1016/j.fuel.2016.05.012

Cited by 12 publications

(5 citation statements)

References 15 publications

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“…Schmidt et al, 41 Sun et al, 43 Guo et al, 47 Yu et al, 48 Battistoni et al 49 Effect of needle motion on cavitation and spray He et al, 17 Komada et al, 51 Zhang et al, 52 Battistoni et al, 53 Gao et al, 62 Multiple injection strategy How et al, 54 Roth et al, 55 Gold et al, 56 Park et al, 57 Wang et al, 58,59,61,63 Yehliu et al 60 Table 2. The topics of the related numerical studies.…”

Section: Simulation On Cavitationmentioning

confidence: 99%

“…The flow was not quite steady at low needle lift and induced high vorticity in the nozzle. 50 Komada et al 51 studied the axial transient need motion effect on the flow and spray through an outward opening injector under dry and wet conditions. It was reported that the breakup process of spray was slow at the initial needle opening stage and the spray passage contracted in closing stages, leading to the increase of turbulence flow and injection velocity.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Dynamics of the in sac cavitating flow for diesel spray with split injection strategy

Liu

Wang

et al. 2020

International Journal of Engine Research

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IC engines consume a large amount of fuel and produce plenty of emissions, thus reducing fuel consumption, and emissions are important. Nozzle internal flow which dominates spray breakup is the key to improve spray atomization and reduce fuel consumption. In this study, microscopic imaging technique was employed to investigate the effects of needle oscillation and injection strategy on the nozzle internal flow under cold (20°C) and hot (140°C) conditions. Needle oscillation was found to affect spray morphology, leading to obvious spray asymmetry under both cold and hot conditions with stronger spray radial propagation under hot condition. Cavitation in the sac appeared when needle oscillated due to enhanced turbulence. Besides, cavitation in the sac was introduced when the needle was insufficiently open due to throttling, especially under hot condition because of reduced viscosity. By contrast, when the split-injection strategy was employed, cavitation was considerably boosted because of the consistent flow transition and the resultant throttling effect. Effective injection duration of the first injection governed the corresponding peak relative cavitation area. The appearance of cavitation was delayed during the initial stage for each split injection after the fuel flows out due to laminar flow regime.

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Section: Simulation On Cavitationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dynamics of the in sac cavitating flow for diesel spray with split injection strategy

Liu

Wang

et al. 2020

International Journal of Engine Research

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“…Komada et al [30] investigated the effect of the transient needle motion on the initial spray formation, using X-ray phase-contrast imaging technique. An obvious needle vibration was found to result in perturbation of the near-nozzle flow and thus to alter the spray intact liquid length and flow breakup.…”

Section: Research Regarding the Effects Of Needle Movement On Spray Cmentioning

confidence: 99%

A Review of Engine Fuel Injection Studies Using Synchrotron Radiation X-ray Imaging

Zhao

et al. 2019

Automot. Innov.

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Fuel spray characteristics directly determine the formation pattern and quality of the fuel/air mixture in an engine, and thus affect the combustion process. For this reason, the improvement and optimization of fuel injection systems is crucial to the development of engine technologies. The fuel jet breakup and atomization process is a complex liquid-gas two-phase turbulent flow system that has not yet been fully elucidated. Owing to the limitations of standard optical measurement techniques, the spray breakup mechanism and its interaction with the nozzle internal flow are still unclear. However, in recent years synchrotron radiation (SR) X-ray imaging technologies have been widely applied in engine fuel injection studies because of the higher energy and brilliance of third-generation SR light sources. This review provides a brief introduction to the development of SR technology and compares the critical parameters of the primary third-generation SR light sources available worldwide. The basic principles and applications of various X-ray imaging technologies with regard to nozzle internal structure measurements, visualization of in-nozzle flow characteristics and quantitative analyses of near-field spray transient dynamics are examined in detail.

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“…The XPCI approach has been also used for investigations of dense sprays. 11,24,25 As the dense spray is directly accessible to the X-ray photons, the energy of the X-ray beam required is typically in the range of 5–14 keV, which is weaker than for the purpose of the internal flow imaging.…”

Section: Introductionmentioning

confidence: 99%

The effect of transient needle lift on the internal flow and near-nozzle spray characteristics for modern GDI systems investigated by high-speed X-ray imaging

Mamaikin

Knorsch

Rogler

et al. 2021

International Journal of Engine Research

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The development of the injector nozzle is a dynamic area in regard of several technical aspects. At first, the internal flow influences the near-field spray characteristics via various phenomena such as cavitation and turbulence. However, these phenomena are not fully understood due to their extremely fast, complex and multiscale nature. Furthermore, it governs the spray targeting inside the combustion chamber. High-speed X-ray imaging of GDI injector nozzles is performed in this study. The experimental results presented are related to the internal flow and primary breakup of discharged liquid jets. The injectors used are equipped with nozzles made of aluminum which have been specially developed for these investigations to enhance optical accessibility. The visualization of the needle motion, in-nozzle flow and the primary breakup region provides several exciting observations. First, the needle lift tracking exhibits short overshooting right before the steady-state of the injection phase. This event leads to a short-term, however, significant change in the associated performance of the breakup. This phenomenon is found to be a consequence of the transient behavior of the in-nozzle flow. It is shown that under some circumstances hydraulic flip may occur during this overshooting period. The primary jet breakup region is visualized and evaluated by means of image processing. Thus, the transient behavior of liquid jet expansion is quantified in the vicinity of the nozzle. It is observed that the liquid jet direction deviates from the hole axis already at the nozzle outlet, which is caused by internal flow characteristics.

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Transient needle motion of an outwardly opening GDI injector and its effects on initial spray formation

Cited by 12 publications

References 15 publications

Dynamics of the in sac cavitating flow for diesel spray with split injection strategy

Dynamics of the in sac cavitating flow for diesel spray with split injection strategy

A Review of Engine Fuel Injection Studies Using Synchrotron Radiation X-ray Imaging

The effect of transient needle lift on the internal flow and near-nozzle spray characteristics for modern GDI systems investigated by high-speed X-ray imaging

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