Numerical simulation of diesel injector nozzle flow and in-cylinder spray evolution

Anvari, Simin; Taghavifar, Hadi; Khalilarya, Shahram; Jafarmadar, Samad; Shervani-Tabar, Mohammad T.

doi:10.1016/j.apm.2016.05.017

Cited by 18 publications

(16 citation statements)

References 37 publications

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“…The intricate multiphase flow and microscale dimension of the nozzle hole as well as the highly turbulent flow of injector demonstrate the significance of numerical simulation in this particular application. The formation of bubbly fuel vapor known as cavitation at the nozzle entrance is desirable in enhancement of spray development, and thus the attempt is targeted to increase the cavitated area and its extension toward the exit section [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Numerical characterization of transient two-phase flow of nozzle under the impact of diesel fuel temperature and injector backpressure

Taghavifar

2020

J Braz. Soc. Mech. Sci. Eng.

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The inner fluid flow within the micro-sac injector is investigated numerically via AVL-Fire CFD code particularly in a microscale dimension of nozzle hole is carried out in the present work. The structural parameters of the injector are left unchanged, while the physical properties of the fluid such as pressure gradient and fluid temperature are taken into account to survey their influence on vapor volume fraction evolution, vapor mass flow rate, cavitation inception, and discharge coefficient. The reliability of modeling results is confirmed by comparing obtained data with experimental one and numerical results of Payri et al. and a close match served as an indication for the accuracy of the methodology. The multiphase modality is activated for the two-fluid model application in the nozzle segment, while the interfacial source term accounts for the momentum exchange of phases in the cavitation drag model. According to results, increasing the fuel temperature is a factor for increasing turbulent kinetic energy; meanwhile, vapor volume fraction at different times shows a different trend. Concerning the discharge coefficient, it seems that increasing the fluid temperature reduces this parameter. In contrast, increasing the pressure gradient leads to a considerable increase in the discharge coefficient.

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Section: Introductionmentioning

confidence: 99%

Numerical characterization of transient two-phase flow of nozzle under the impact of diesel fuel temperature and injector backpressure

Taghavifar

2020

J Braz. Soc. Mech. Sci. Eng.

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“…A computational fluid dynamics (CFD) model was conducted by Zhou et al [20] using a Taylor Analogy Breakup (TAB) model to study atomization with three different types of mesh accuracies. Comparing the Reynoldsaveraged Navier-Stokes (RANS) and large eddy simulation (LES) models, it was also concluded that random variations of three-dimensional turbulent vortices could be easily captured through the LES model in the fluid field [20,21]. However, the process of deformation and shedding of spray columns could not be directly obtained through the discrete droplet model (DDM) method [20].…”

Section: Introductionmentioning

confidence: 99%

Influence of sac structure on cavitation and gas ingestion at the end of injection

Hua

et al. 2020

J Braz. Soc. Mech. Sci. Eng.

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A comparative study using different sac structures was conducted focusing on the cavitation morphology inside a diesel nozzle. Cavitation phenomena play important roles in the flow field during fuel injection at the end of injection, which causes high-temperature gas ingestion. This can lead to coke formation inside the orifice (a hole of the nozzle where cavitation mainly occurs), further influencing the injection atomization in the cylinder. Using visual experiments and a finite volume method two-phase, three-component multiphase flow solver, the flow process in the nozzle at the end of injection was tested and simulated, and the influence of sacs with three different wall curvatures on the cavitation and gas ingestion was analyzed. The results demonstrated that cavitation occurred successively in the orifice and sac at the end of injection. The cavitation amount in the sac was larger, and two cavitation forms were produced: vortex and bulk cavitation. For narrow and straight sacs, bulk cavitation played an important role, and the amount of cavitation increased. The prolongation of the lower pressure duration inside of the nozzle decreased the fuel outflow, eventually leading to a decrease in gas ingestion. When vortex cavitation occurred in the sac, the second matrix invariant Q of the velocity gradient tensor ∇V was positively correlated with the volume of the vortex cavitation. The smaller the vortex core zone was, the lower the friction dissipation in the flow field was; under these conditions, cavitation occurred more easily in the sac.

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“…For example, Reynolds Averaged Navier-Stokes (RANS) is commonly used in CFD to perform 3D simulations [7,8], characterized by reasonable computational costs. However, it allows the no origins, e.g., cyclic variabilities [9]. Large Eddy Simulation (LES) seems to be better adapted to such situations [10].…”

Section: Introductionmentioning

confidence: 99%

Spray dynamics of HVO and EN590 diesel fuels

Cheng

Hulkkonen

Kaario

et al. 2019

Fuel

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This investigation aims at quantifying the spray dynamics of diesel-like injection at the steady stage. A 1D model based on momentum flux conservation and combined with Gaussian radial profiles is derived to predict the axial and radial velocity, fuel concentration, liquid volume fraction and density distribution within the steady spray field. To validate the model over a range of conditions, global quantities such as spray tip penetration, spray cone angle, spray tip velocity, and spray volume was measured by diffused back-illumination imaging. The spray characteristics of hydrotreated vegetable oil (HVO) and European standard diesel fuel (EN590) under different ambient air conditions (36kg/m 3 and 115kg/m 3 ) are compared to further predict the local velocity, fuel concentration, liquid volume fraction and density distribution. The present results indicate that an accurate model of diesellike spray evolution can be obtained for different fuel types and ambient air densities.

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Numerical simulation of diesel injector nozzle flow and in-cylinder spray evolution

Cited by 18 publications

References 37 publications

Numerical characterization of transient two-phase flow of nozzle under the impact of diesel fuel temperature and injector backpressure

Numerical characterization of transient two-phase flow of nozzle under the impact of diesel fuel temperature and injector backpressure

Influence of sac structure on cavitation and gas ingestion at the end of injection

Spray dynamics of HVO and EN590 diesel fuels

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