Coupling level set/VOF/ghost fluid methods: Validation and application to 3D simulation of the primary break-up of a liquid jet

Ménard, Thibaut; Tanguy, Sébastien; Berlemont, Alain

doi:10.1016/j.ijmultiphaseflow.2006.11.001

Cited by 434 publications

(349 citation statements)

References 19 publications

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“…To simulate such flow, we use an in-house code generally applied for the study of liquid jet atomization [13]. The following incompressible Navier-Stokes equations are solved thanks to a projection method and coupled with interface transport equation performed by a CLSVOF method [14,13]:…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Comparison between numerical and experimental water-in-oil dispersion in a microchannel

Desjonquéres

Ménard

Tarlet

et al. 2017

Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems

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The dispersion of water inside a flow of oil is investigated in a microfluidic device, producing a water-in-oil emulsion. The liquid-liquid flow mainly differs from those presented in existing literature through its high capillary number (between 3 and 14), and in the head-on collision between water and oil streams. By comparing with experimental data, numerical simulations can provide more information about the topology of the flow. A coupled Volume of Fluid and Level Set method (CLSVOF) is used to treat the interface between both phases and incompressible Navier-Stokes equations are solved. Three set of parameters, close to those in the experimental setup, are investigated to compare experimental and numerical results. The comparison between experiments and simulation provides a precise knowledge of the liquid-liquid dispersion process and the overall flow pattern within the microfluidic device. KeywordsMicrochannel, water-in-oil dispersion, liquid-liquid flow Introduction Liquid-liquid dispersion within microfluidic devices has become an important issue over the last decade [1]. An emulsion is defined as the temporarily stable dispersion of a liquid into another one that is not miscible [2]. When the scale of the liquid-liquid flow is smaller than its capillary length [3], interfacial tension dominates over shear stress and gravity [4], making the dispersion highly reproducible in slow conditions [5]. These slow conditions ensure a highly monodisperse emulsion [6], that is usually appropriate for targeted applications like microreaction synthesis [7]. However, other application like high flow-rate biofuel production [8] benefit from the considerably increased surface-to-volume ratio [9,10] of microfluidic liquid-liquid dispersion. In order to better understand the physics of microfluidic in high flow-rate liquid-liquid dispersion, experimental results of the obtained mean diameter and liquid-liquid flow photographies [8] are compared to numerical results. At the present stage, a quantitative validation of the model is not obtained, but we present a qualitative comparison of the liquid-liquid flow pattern. In a first part, experimental material and methods are presented, then numerical methods used to investigate such flows are briefly detailed. Finally, first comparisons are discussed.

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Section: Methodsmentioning

confidence: 99%

“…The following incompressible Navier-Stokes equations are solved thanks to a projection method and coupled with interface transport equation performed by a CLSVOF method [14,13]:…”

Section: Methodsmentioning

confidence: 99%

Comparison between numerical and experimental water-in-oil dispersion in a microchannel

Desjonquéres

Ménard

Tarlet

et al. 2017

Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems

View full text Add to dashboard Cite

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“…Direct numerical simulation (DNS) describes the whole atomization process from the larger scales to the smaller ones. They are generally based on sharp interface computed by Level-Set method [17], Volume-of-Fluid [18], and derived methods such as Refined Level-Set [19] and Coupled Level-Set and Volume-of-Fluid [20]- [21]. These approaches require a large computational effort and can be combined with AMR method [22] to reduce the number of cells in the numerical domain or Euler-Lagrangian coupling (in a discrete element sense) [23].…”

Section: Numerical Approachesmentioning

confidence: 99%

Multi-scale Eulerian-Lagrangian simulation of a liquid jet in cross-flow under acoustic perturbations

Thuillet¹,

Zuzio²,

Rouzaud³

et al. 2017

Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems

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The design of modern aeronautical propulsion systems is constantly optimized to reduce pollutant emissions while increasing fuel combustion efficiency. In order to get a proper mixing of fuel and air, Liquid Jets Injected in gaseous Crossflows (LJICF) are found in numerous injection devices. However, should combustion instabilities appear in the combustion chamber, the response of the liquid jet and its primary atomization is still largely unknown. Coupling between an unstable combustion and the fuel injection process has not been well understood and can result from multiple basic interactions. The aim of this work is to predict by numerical simulation the effect of an acoustic perturbation of the shearing air flow on the primary breakup of a liquid jet. Being the DNS approach too expensive for the simulation of complex injector geometries, this paper proposes a numerical simulation of a LJICF based on a multiscale approach which can be easily integrated in industrial LES of combustion chambers. This approach results in coupling of two models: a two-fluid model, based on the Navier-Stokes equations for compressible fluids, able to capture the largest scales of the jet atomization and the breakup process of the liquid column; and a dispersed phase approach, used for describing the cloud of droplets created by the atomization of the liquid jet. The coupling of these two approaches is provided by an atomization and re-impact models, which ensure liquid transfer between the two-fluid model and the spray model. The resulting numerical method is meant to capture the main jet body characteristics, the generation of the liquid spray and the formation of a liquid film whenever the spray impacts a solid wall. Three main features of the LJICF can be used to describe, in a steady state flow as well as under the effect of the acoustic perturbation, the jet atomization behavior: the jet trajectory, the jet breakup length and droplets size and distribution. The steady state simulations provide good agreement with ONERA experiments conducted under the same conditions, characterized by a high Weber number (We>150). The multiscale computation gives the good trajectory of the liquid column and a good estimation of the column breakup location, for different liquid to air momentum flux ratios. The analysis of the droplet distribution in space is currently undergoing. A preliminary unsteady simulation was able to capture the oscillation of the jet trajectory, and the unsteady droplets generation responding to the acoustic perturbation. Keywords multiscale numerical simulation, liquid jet in gaseous crossflow, acoustic perturbation, Euler-Lagrange coupling IntroductionThe liquid jet in crossflow (LJICF) configuration covers several applications in engineering systems, such as combustion, chemical or even agriculture fields. Particularly in aircraft combustion chambers, systems where the fuel jet is injected normally into an air crossflow are commonly used. Compared with a free jet into a quiescent flow, this configuration enab...

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“…On the other hand, engine sprays, and sprays in general, could be better described using a continuum for both the liquid and the gas phases, where conservation laws are solved under Eulerian flow assumptions and grid is refined until its resolution allows for solving droplets or bubbles without introducing any conceptual particles. In such a case, a transport equation for an indicator function is used to track the liquid-gas interface [11,12,13]. In this work the Volume-of-fluid (VOF) approach is adopted: governing equations are solved for a fluid whose thermophysical properties are a weighted average of the liquid and the vapor phases according to the liquid fraction.…”

Section: Introductionmentioning

confidence: 99%

VOF Simulation of The Cavitating Flow in High Pressure GDI Injectors

Giussani¹,

Montorfano²,

Piscaglia³

et al. 2017

Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems

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The paper describes the development in the OpenFOAM ® technology of a dynamic multiphase Volume-of-Fluid (VoF) solver, supporting mesh handling with topological changes, that has been used for the study of the physics of the primary jet breakup and of the flow disturbance induced by the nozzle geometry during the injector opening event in high-pressure Gasoline Direct Injection (GDI) engines. Turbulence modeling based on a scale-resolving approach has been applied, while phase change of fuel is accounted by means of a cavitation model that has been coupled with the VOF solver. Simulations have been carried out on a 6-hole prototype injector, especially developed for investigations in the framework of the collaborative project FUI MAGIE and provided by Continental Automotive SAS. Special attention has been paid to the domain decomposition strategy and to the code development of the solver, to ensure good load balancing and to minimize inter-processor communication, to achieve good performance and also high scalability on large computing clusters. KeywordsVolume-of-fluid, GDI injectors, topologically changing mesh, hybrid RANS/LES, cavitation, OpenFOAM ® Introduction Turbulence certainly has a direct impact on thermodynamic efficiency, brake power and emissions of the engine, since its influence extends from volumetric efficiency to air/fuel mixing, combustion and heat transfer. In a gasoline engine, there are two strategies for injecting the fuel: Port Fuel Injection (PFI), a well known technology to favor air/fuel mixing, and Gasoline Direct Injection (GDI), which consists in injecting the fuel directly into the cylinder. GDI is becoming a common solution in automotive industry since it allows for a great flexibility in the air/fuel ratio, leading to low fuel consumption and emissions at light loads (lean or stratified mode) and high power output during rapid accelerations and heavy loads (power mode) [1,2]. These different conditions are not only related to the amount of fuel injected into the combustion chamber, but also to the way the injection is performed: level of atomization, penetration and diffusion of fuel. Experimental campaigns showed that spray formation is mainly influenced by the geometry of the injector itself (L/D ratio, number of holes, internal geometry, etc.) [3,4], the operating pressure and the needle lift curve [5]. Fuel is characterized by high velocities (order of hundreds of meters per second) and reduced timescales, so that time-transient phenomena play an important role. Moreover, because of the strong acceleration of the liquid phase inside the injector nozzle, pressure may drop below the saturation value causing the onset of cavitation, which strongly modifies the internal flow field due to the presence of bubbles. Hence, a better comprehension of spray characteristics could help to improve engine performance and injector design. Simulating the injector opening event and the spray primary breakup are still on the frontier of modern modeling science. Since primary breakup is ...

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Coupling level set/VOF/ghost fluid methods: Validation and application to 3D simulation of the primary break-up of a liquid jet

Cited by 434 publications

References 19 publications

Comparison between numerical and experimental water-in-oil dispersion in a microchannel

Comparison between numerical and experimental water-in-oil dispersion in a microchannel

Multi-scale Eulerian-Lagrangian simulation of a liquid jet in cross-flow under acoustic perturbations

VOF Simulation of The Cavitating Flow in High Pressure GDI Injectors

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