Numerical simulation of incipient cavitation flow in a nozzle of fuel injector

Sou, Akira; Biçer, Barış; Tomiyama, Akio

doi:10.1016/j.compfluid.2014.07.011

Cited by 89 publications

(76 citation statements)

References 12 publications

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“…Duke et al 35 expect that large vortical structures within the nozzle flows strongly interact with cavitation structures and therefore suggest to perform Large-Eddy Simulations (LESs). Recent studies of Salvador et al 36 and Sou et al 37 present incompressible LES of turbulent, cavitating flows using a Euler-Lagrangian Rayleigh-Plesset model. Schnerr et al 30 present a compressible framework for the simulation of cavitating flows.…”

Section: -2 öRley Et Almentioning

confidence: 99%

Large-eddy simulation of cavitating nozzle flow and primary jet break-up

et al. 2015

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We employ a barotropic two-phase/two-fluid model to study the primary break-up of cavitating liquid jets emanating from a rectangular nozzle, which resembles a high aspect-ratio slot flow. All components (i.e., gas, liquid, and vapor) are represented by a homogeneous mixture approach. The cavitating fluid model is based on a thermodynamic-equilibrium assumption. Compressibility of all phases enables full resolution of collapse-induced pressure wave dynamics. The thermodynamic model is embedded into an implicit large-eddy simulation (LES) environment. The considered configuration follows the general setup of a reference experiment and is a generic reproduction of a scaled-up fuel injector or control valve as found in an automotive engine. Due to the experimental conditions, it operates, however, at significantly lower pressures. LES results are compared to the experimental reference for validation. Three different operating points are studied, which differ in terms of the development of cavitation regions and the jet break-up characteristics. Observed differences between experimental and numerical data in some of the investigated cases can be caused by uncertainties in meeting nominal parameters by the experiment. The investigation reveals that three main mechanisms promote primary jet break-up: collapse-induced turbulent fluctuations near the outlet, entrainment of free gas into the nozzle, and collapse events inside the jet near the liquid-gas interface. C 2015 AIP Publishing LLC. [http://dx

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Section: -2 öRley Et Almentioning

confidence: 99%

Large-eddy simulation of cavitating nozzle flow and primary jet break-up

et al. 2015

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“…On the other hand, when the outflow is into a gas, experiments [23,63] have shown that the liquid flow is unable to reattach to the nozzle walls at the lowest CN values. Cavitation disappears, and a jet that consists entirely of liquid (a glass-like flow [63]) becomes completely detached from the nozzle walls: this regime is referred to as hydraulic flip [18,64]. The latter circumstance causes minimum values of the discharge coefficient [63], and thus reduces the liquid flow penetration in the downstream environment, which in turn results in altered spray characteristics.…”

Section: Different Hydrodynamic Cavitation Regimes In Nozzlesmentioning

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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“…The cavitation model adopted for the current investigation and the related settings have been assessed simulating two reference cases, i.e., the experiment proposed by Winklhofer et al [46] and the more recent experiment proposed by Sou et al [47]. As recently reported in [19], many other contributors [48,49] have considered the experiment of Winklhofer as a significant reference case.…”

Section: Cavitation Model Assessmentmentioning

confidence: 99%

“…The incipience and the development of cavitation is well reproduced by the simulation, as indicated by the contours of liquid mass fraction shown in Figure 8. The quantitative comparison between the experiment and the simulation is reported in Figure 9, where the available data on velocity profile provided by Sou [47] are compared with the simulations. The Moving to the second assessment phase, the experiment of Sou [47] has been reproduced by simulation.…”

Section: Cavitation Model Assessmentmentioning

confidence: 99%

“…On the other side, the cavitation patterns related to the three fundamental conditions, as evidenced in [46], have been consistently reproduced, as reported in Figure 7; it has to be explicitly mentioned that the cavitation patterns observed by Winklhofer were fluctuating, due to the highly turbulent flow environment and they have been obtained by an ensemble averaging process of a set of twenty images taken under the same operating conditions. Moving to the second assessment phase, the experiment of Sou [47] has been reproduced by simulation. The experiment consists of a flow through a transparent channel allowing the visualization (based on Laser Doppler Velocimetry) of cavitation incipience and development.…”

Section: Cavitation Model Assessmentmentioning

confidence: 99%

See 1 more Smart Citation

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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Numerical simulation of incipient cavitation flow in a nozzle of fuel injector

Cited by 89 publications

References 12 publications

Large-eddy simulation of cavitating nozzle flow and primary jet break-up

Large-eddy simulation of cavitating nozzle flow and primary jet break-up

Fluid dynamics of acoustic and hydrodynamic cavitation in hydraulic power systems

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

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