Experimental Study of Cavitation in the Nozzle Hole of Diesel Injectors Using Transparent Nozzles

Chaves, H.; Knapp, Marcus; Kubitzek, A.; Obermeier, F.; Schneider, Torsten

doi:10.4271/950290

Cited by 228 publications

(127 citation statements)

References 9 publications

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“…Some of the research conducted in real-size and model injectors with optical access has led to questions as to whether cavitation phenomena in injectors are directly scalable, even when Reynolds and cavitation numbers have been matched on models. Arcoumanis et al [19] made a comparison between large-scale and real-size Diesel nozzles and found that cavitation in models occurred in the form of foamy clouds of bubbles, similar to those of Soteriou et al [21]; in real-size injectors though, cavitation appeared in the form of large clear voids, similar to those of Chaves et al [6]. Such results suggest that the nature of cavitation inception may change in scaled-up models and that bubble scaling factors are not well understood.…”

Section: Introductionmentioning

confidence: 82%

“…the fuel does not simply 'flash boil' upon release into the atmosphere, but the process of 'boiling' begins inside the injector. Although the effect of two-phase flow 13 inside the nozzles has been shown to affect primary break-up [6,17,18] and spray cone angles, the coupling with flash-boiling is not well understood and must be investigated further in optical nozzles.…”

Section: Macroscopic and Near-nozzle Imagingmentioning

confidence: 99%

“…Most previous studies have focused on cavitation imaging in optical models of Diesel nozzles, typically enlarged 20, with few studies on real-size nozzles [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. Moreover, only limited work can be found on quantitative flow data in scaled-up or real Diesel and gasoline injectors, e.g.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Cavitation, primary break-up and flash boiling of gasoline, iso-octane and n-pentane with a real-size optical direct-injection nozzle

Serras-Pereira

Romunde

Aleiferis

et al. 2010

Fuel

130

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Improvements to the direct-injection spark-ignition combustion system are necessary if the potential reductions in fuel consumption and emissions are to be fully realized in the near future. One critical link in the optimization process is the design and performance of the injectors used for fuel atomization. Multi-hole injectors have become the state-of-the-art choice for gasoline direct injection engines due to their flexibility in fuel targeting by selection of the number and angle of the nozzle holes, as well as due to their demonstrated stability of performance under a wide range of operating conditions. Recently there has been increased attention devoted to the study of the flow through the internal passages of injectors because of the presence of particular fluid phenomena, such as large scale vortical motion and cavitation patterns, which have been shown to influence the characteristics of primary break-up. Understanding how cavitation can be used to improve spray atomisation is essential for optimising mixture preparation quality under early injection and stratified engine operating conditions but currently no data exist for injector-body temperatures representative of real engine operation, particularly at low-load conditions that can also lead to phase change due to fuel flash boiling. This paper outlines results from an experimental imaging investigation into the effects of fuel properties, temperature and pressure conditions on the extent of cavitation, flash boiling and, subsequently, primary break-up. This was achieved by the use of a real-size transparent nozzle of a gasoline injector from a modern direct-injection combustion system. Gasoline, iso-octane and n-pentane fuels were used at 20 and 90 °C injector-body temperatures for ambient pressures of 0.5 bar and 1.0 bar in order to simulate early homogeneous injection strategies for part-load and wide-open-throttle engine operation.3

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Section: Introductionmentioning

confidence: 82%

Section: Macroscopic and Near-nozzle Imagingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Cavitation, primary break-up and flash boiling of gasoline, iso-octane and n-pentane with a real-size optical direct-injection nozzle

Serras-Pereira

Romunde

Aleiferis

et al. 2010

Fuel

130

View full text Add to dashboard Cite

show abstract

“…However, other researches [5][6][7][8][9][10][11] point to the visualization of the flow inside the nozzle with the goal to observe the cavitation phenomenon and its influence in the spray development. In these researches, different nozzle models have been developed with optical materials that allow the visualization inside the hole such as quartz (fused silica, SiO2) and methacrylate.…”

Section: Introductionmentioning

confidence: 99%

A Technique to Match the Refractive Index of Different Diesel Fuels with the Refractive Index of Transparent Materials to Improve the Experimental Visualization

2016

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“…Different nozzle prototypes have been realized with optical materials, such as quartz and methacrylate, which allow the velocity components inside the nozzles to be visualized [24]: some studies have been performed with planar nozzles, in order to be able to observe cavitation more easily [25][26][27][28], while others have been conducted with large-scale cylindrical nozzles [23,[29][30][31][32], in order to facilitate the visualization of the phenomena. Observations in the laboratory can be extrapolated to naturalscale flows [33][34][35][36], through the use of a scale model and different fuels, and the obtained results can then be integrated with data from a few experimental studies on cavitation in real-size orifices [35,37,38].…”

Section: Introductionmentioning

confidence: 99%

Fluid dynamics of acoustic and hydrodynamic cavitation in hydraulic power systems

Ferrari¹

2017

Proc. R. Soc. A.

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Cavitation is the transition from a liquid to a vapour phase, due to a drop in pressure to the level of the vapour tension of the fluid. Two kinds of cavitation have been reviewed here: acoustic cavitation and hydrodynamic cavitation. As acoustic cavitation in engineering systems is related to the propagation of waves through a region subjected to liquid vaporization, the available expressions of the sound speed are discussed. One of the main effects of hydrodynamic cavitation in the nozzles and orifices of hydraulic power systems is a reduction in flow permeability. Different discharge coefficient formulae are analysed in this paper: the Reynolds number and the cavitation number result to be the key fluid dynamical parameters for liquid and cavitating flows, respectively. The latest advances in the characterization of different cavitation regimes in a nozzle, as the cavitation number reduces, are presented. The physical cause of choked flows is explained, and an analogy between cavitation and supersonic aerodynamic flows is proposed. The main approaches to cavitation modelling in hydraulic power systems are also reviewed: these are divided into homogeneous-mixture and twophase models. The homogeneous-mixture models are further subdivided into barotropic and baroclinic models. The advantages and disadvantages of an implementation of the complete Rayleigh-Plesset equation are examined.

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Experimental Study of Cavitation in the Nozzle Hole of Diesel Injectors Using Transparent Nozzles

Cited by 228 publications

References 9 publications

Cavitation, primary break-up and flash boiling of gasoline, iso-octane and n-pentane with a real-size optical direct-injection nozzle

Cavitation, primary break-up and flash boiling of gasoline, iso-octane and n-pentane with a real-size optical direct-injection nozzle

A Technique to Match the Refractive Index of Different Diesel Fuels with the Refractive Index of Transparent Materials to Improve the Experimental Visualization

Fluid dynamics of acoustic and hydrodynamic cavitation in hydraulic power systems

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