Numerical analyses of transient flow characteristics within each nozzle hole of an asymmetric diesel injector

Xue, Fuying; Luo, Fei; Cui, Huifeng; Moro, Adams; Zhou, Ling

doi:10.1016/j.ijheatmasstransfer.2016.08.027

Cited by 27 publications

(9 citation statements)

References 38 publications

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“…In the fourth approach we find works such as Poorghasemi [28], which achieves a model that simulates 3D combustion and predicts emissions for direct injection (DI) and the controlled compression ignition method (RCCI) or Dezhi work Zhou [29] that studies the effect of injection timing on the start injection rate on emissions and combustion characteristics in a direct injection compression engine (DICI). Yu [30] that follows a multiphase model large eddy simulation-volume of fluid (LES-VOF) or the work of Fuying Xue [31] that opts for a homogeneous flow approach and fluid volume method to analyze the flow in each orifice in an asymmetric injection nozzle using a liquid-gas phase flow model. But the trend is clear to opt for CFD analysis, in this group we have worked like those of Marčič [32] who model the liquid jet phase using CFD and effects of eccentric movements [33].…”

Section: Discussionmentioning

confidence: 99%

Injection systems in diesel engines and their theoretical-experimental study: a review

Duarte¹,

Orozco²,

Caicedo³

2018

ces

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The injection systems have had a strong evolution in recent years, going from lowpressure system of a mechanical drive to complex high-pressure electronic systems. The electronics applied to this type of systems has allowed handling sequential injections and increasing the injection pressure. In the present work a review of the evolution of the injection systems in the last 20 years is made and how techniques have been developed to model the hydrodynamic behavior of the injectors in Diesel internal combustion engines. With this review, the trends for the modeling of the injection process are visualized, which has an important impact on the thermodynamic modeling and the prediction of the indicator parameters in Diesel internal combustion engines. This review allows to visualize the future development of this type of systems and the implications they have on the performance of internal combustion engines and the thermodynamic modeling of them. The optimization in the operation of diesel engines is possible by improving the operation of injection systems, which has led to more powerful engines but smaller.

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Section: Discussionmentioning

confidence: 99%

Injection systems in diesel engines and their theoretical-experimental study: a review

Duarte¹,

Orozco²,

Caicedo³

2018

ces

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“…As recently reported in [19], many other contributors [48,49] have considered the experiment of Winklhofer as a significant reference case. This experiment is based on the investigation of an optically accessible channel (inlet section 0.300 × 0.301 mm; outlet section 0.284 × 0.301 mm; 1 mm length, 0.02 mm inlet curvature radius).…”

Section: Cavitation Model Assessmentmentioning

confidence: 99%

“…The results reported in the literature have highlighted that the flow field upstream of the holes is directly affected by the needle position during injection. In more detail, the position of the needle determines the flow characteristics at each hole inlet, influencing the downstream fuel flow [18][19][20].…”

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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“…A group-hole nozzle (GHN) is a variation of this design, in which rather than being uniformly spaced, the nozzle holes are spaced closely together to form a group, with the groups, if more than one, being spaced around the tip. Because of their potential benefits to fuel consumption and emissions [16], GHNs, particularly in the form of a twin-hole nozzle (THN), have recently been a focus of interest [9,10,[16][17][18][19][20]. An important feature of GHNs is they enhance spray to spray interaction whether through direct merging of closely spaced sprays [9], or indirectly through modification to air entrainment into individual but unmerged sprays as they compete for the surrounding air.…”

Section: Introductionmentioning

confidence: 99%

“…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].…”

Section: Introductionmentioning

confidence: 99%

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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Numerical analyses of transient flow characteristics within each nozzle hole of an asymmetric diesel injector

Cited by 27 publications

References 38 publications

Injection systems in diesel engines and their theoretical-experimental study: a review

Injection systems in diesel engines and their theoretical-experimental study: a review

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

Spray flow structure from twin-hole diesel injector nozzles

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