Ultrafast X-ray study of multi-hole GDI injector sprays: Effects of nozzle hole length and number on initial spray formation

Moon, Seoksu; Komada, Keisuke; Sato, Kiyotaka; Yokohata, Hideaki; Wada, Yoshitaka; Yasuda, Nobuhiro

doi:10.1016/j.expthermflusci.2015.03.027

Cited by 56 publications

(28 citation statements)

References 21 publications

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“…However, the 170 strong fluctuations in the radiography data suggest that this is not simply a measurement error. Moon et al [69] have observed that multi-hole GDIs experience more pronounced transient fluctuations than diesel injectors, and propose that the low needle lift may be responsible for this phenomenon. Recent simulations [70] which reveal the complexity of the flow past the needle seat and in the sac support the hypothesis that GDIs exhibit strong and persistent transients in ROI under more realistic operating conditions.…”

Section: Hydraulic and Mechanical Charaterizationmentioning

confidence: 99%

Internal and near nozzle measurements of Engine Combustion Network “Spray G” gasoline direct injectors

Duke

Kastengren

Matusik

et al. 2017

Experimental Thermal and Fluid Science

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Gasoline direct injection (GDI) sprays are complex multiphase flows. When compared to multi-hole diesel sprays, the plumes are closely spaced, and the sprays are more likely to interact. The effects of multi-jet interaction on entrainment and spray targeting can be influenced by small variations in the mass fluxes from the holes, which in turn depend on transients in the needle movement and small-scale details of the internal geometry. In this paper, we present a comprehensive overview of a multi-institutional effort to experimentally characterize the internal geometry and near-nozzle flow of the Engine Combustion Network (ECN) Spray G gasoline injector. In order to develop a complete picture of the near-nozzle flow, a standardized setup was shared between facilities. A wide range of techniques were employed, including both x-ray and visible-light diagnostics. The novel aspects of this work include both new experimental measurements, and a comparison of the results across different techniques and facilities. The breadth and depth of the data reveal phenomena which were not apparent from analysis of the individual data sets. We show that plume-to-plume variations in the mass fluxes from the holes can cause large-scale asymmetries in the entrainment field and spray structure.Both internal flow transients and small-scale geometric features can have an effect on the external flow. The sharp turning angle of the flow into the holes also causes an inward vectoring of the plumes relative to the hole drill angle, which increases with time due to entrainment of gas into a low-pressure region between the plumes. These factors increase the likelihood of spray collapse with longer injection durations.

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Section: Hydraulic and Mechanical Charaterizationmentioning

confidence: 99%

Internal and near nozzle measurements of Engine Combustion Network “Spray G” gasoline direct injectors

Duke

Kastengren

Matusik

et al. 2017

Experimental Thermal and Fluid Science

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show abstract

“…The SHN also shows a positive change in mean penetration gradient at around 30 ls, while for the THNs, this is delayed to around 90-100 ms. Slower needle lift has been observed for multi-hole nozzles relative to a similar SHN [13] with the possible cause being lower nozzle sac pressure due to their higher mass flow requirements. Although not shown in Fig.…”

Section: Transient Resultsmentioning

confidence: 94%

“…Aside from altering nozzle exit velocities [13], this could also alter the nozzle needle lift profile particularly affecting the initial opening and closing transients [13,21]. Hole number and hole position have also been shown to strongly influence spray stability and near field spray breakup [13,18,20,21]. This influence is thought to arise from modification to the internal flow structure which accompanies change to these parameters.…”

Section: Introductionmentioning

confidence: 96%

“…For example, relative to a SHN with the same orifice diameter, the increased mass discharge which accompanies the increased number of holes in a GHN is likely to lead to reduced nozzle sac pressure [17]. Aside from altering nozzle exit velocities [13], this could also alter the nozzle needle lift profile particularly affecting the initial opening and closing transients [13,21]. Hole number and hole position have also been shown to strongly influence spray stability and near field spray breakup [13,18,20,21].…”

Section: Introductionmentioning

confidence: 96%

“…There is however a growing recognition of the need to study nozzles which are more representative of the multi-hole nozzles used in engines (e.g. [8][9][10][11][12][13][14][15]) if advances are to be made in our understanding of spray structure and dynamics, and to improve engine performance.…”

Section: Introductionmentioning

confidence: 99%

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Spray flow structure from twin-hole diesel injector nozzles

Nguyen

Duke

Kastengren

et al. 2017

Experimental Thermal and Fluid Science

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a b s t r a c tTwo techniques were used to study non-evaporating diesel sprays from common rail injectors which were equipped with twin-hole and single-hole nozzles for comparison. To characterise the sprays, high speed optical imaging and X-ray radiography were used. The former was performed at the Laboratory for Turbulence Research in Aerospace and Combustion (LTRAC) at Monash University, while the latter was performed at the 7-BM beamline of the Advanced Photon Source (APS) at Argonne National Laboratory. The optical imaging made use of high temporal, high spatial resolution spray recordings on a digital camera from which peripheral parameters in the initial injection phase were investigated based on edge detection. The X-ray radiography was used to explore quantitative mass distributions, which were measured on a point-wise basis at roughly similar sampling rate. Three twin-hole nozzles of different subtended angles and a single-hole nozzle were investigated at injection pressure of 1000 bar in environments of 20 bar back pressure. Evidence of strong cavitation was found for all nozzles examined with their C D ranging from 0.62 to 0.69. Penetration of the twin-hole nozzles was found to lag the single-hole nozzle, before the sprays merged. Switching in hole dominance was observed from one twin-hole nozzle, and this was accompanied by greater instability in mass flow during the transient opening phase of the injectors.

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X-Ray Phase Contrast Methods

Mayo¹,

Endrizzi²

2019

Handbook of Advanced Nondestructive Evaluation

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Ultrafast X-ray study of multi-hole GDI injector sprays: Effects of nozzle hole length and number on initial spray formation

Cited by 56 publications

References 21 publications

Internal and near nozzle measurements of Engine Combustion Network “Spray G” gasoline direct injectors

Internal and near nozzle measurements of Engine Combustion Network “Spray G” gasoline direct injectors

Spray flow structure from twin-hole diesel injector nozzles

X-Ray Phase Contrast Methods

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