Adaptive collision meshing and satellite droplet formation in spray simulations

Hou, Shuhai; Schmidt, David P.

doi:10.1016/j.ijmultiphaseflow.2006.02.013

Cited by 43 publications

(15 citation statements)

References 29 publications

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“…Grid convergence studies for fuel spray with a Reynolds Averaged Navier Stokes (RANS) turbulence model were conducted by Senecal et al [16][17] on finest mesh resolutions of 0.03125mm by using AMR and fixed embedding techniques. Schmidt and Senecal [18] and Hou and Schmidt [19] developed a new collision algorithm with a secondary collision mesh. Schmidt and Rutland [20] and Are et al [21] developed a collision sub model, a collision mesh approach, and second-order gas-to-liquid coupling to better predict the dense spray on a typical mesh size using the RANS approach within the Lagrangian-Eulerian framework.…”

Section: Introductionmentioning

confidence: 99%

Eulerian CFD Modeling of Coupled Nozzle Flow and Spray with Validation Against X-Ray Radiography Data

Xue

Battistoni

Som

et al. 2014

SAE Int. J. Engines

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High injection pressure and direct injection techniques are extensively implemented to achieve better air-fuel mixture formation for controlling combustion and pollutant formation processes. This has necessitated further understanding of the in-nozzle flow and near-nozzle spray phenomena both experimentally and numerically. For example, researchers across the world have made many contributions in these areas in the Engine Combustion Network (ECN) [4] in the past few years.The discrete droplet method (DDM) [5] has been widely used in the traditional Lagrangian-Eulerian approach for modeling fuel sprays in Internal Combustion Engines (ICEs). The Lagrangian-Eulerian approach treats the gas-phase in an Eulerian manner while the liquid phase is modeled in a Abstract This paper implements a coupled approach to integrate the internal nozzle flow and the ensuing fuel spray using a Volume-of-Fluid (VOF) method in the CONVERGE CFD software. A VOF method was used to model the internal nozzle two-phase flow with a cavitation description closed by the homogeneous relaxation model of Bilicki and Kestin [1]. An Eulerian single velocity field approach by Vallet et al. [2] was implemented for near-nozzle spray modeling. This Eulerian approach considers the liquid and gas phases as a complex mixture with a highly variable density to describe near nozzle dense sprays. The mean density is obtained from the Favreaveraged liquid mass fraction. The liquid mass fraction is transported with a model for the turbulent liquid diffusion flux into the gas. Simulations were performed in three dimensions and the data for validation were obtained from the x-ray radiography measurements Kastengren et al. [3] at Argonne National Laboratory for a diesel fuel surrogate n-dodecane. The quantitative and time-resolved data consisting of fuel mass distribution and spray velocity in the near nozzle dense spray region are used to validate the coupled Eulerian approach. A standard k-ε Reynolds Averaged Navier Stokes based turbulence models is implemented in this study and the influence of model constants are evaluated. The effect of grid size is also evaluated by comparing the fuel distribution against experimental data. Finally, the fuel distribution predicted by the coupled Eulerian approach is compared against classical Lagrangian spray model results. The coupled Eulerian approach provides a unique way of coupling the nozzle flow and sprays so that the effects of in-nozzle flow can be directly realized on the fuel spray.

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Section: Introductionmentioning

confidence: 99%

Eulerian CFD Modeling of Coupled Nozzle Flow and Spray with Validation Against X-Ray Radiography Data

Xue

Battistoni

Som

et al. 2014

SAE Int. J. Engines

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“…Grid convergence studies for fuel spray were conducted by Senecal et al (2013a) with a Reynolds Averaged Navier Stokes (RANS) turbulence model and by Senecal et al (2013b); Xue et al (2013b); Senecal et al (2014) with different sub-grid scale models in large eddy simulations (LES) on finest mesh resolutions of 0.03125mm by using AMR and fixed embedding techniques. Schmidt and Senecal (2002) and Hou and Schmidt (2006) developed a new collision algorithm with a secondary collision mesh. Schmidt and Rutland (2004) and Are et al (2005) developed a collision sub model, a collision mesh approach, and secondorder gas-to-liquid coupling to better predict the dense spray on a typical mesh size using the RANS approach within the Lagrangian-Eulerian framework.…”

mentioning

confidence: 99%

An Eulerian CFD model and X-ray radiography for coupled nozzle flow and spray in internal combustion engines

Xue

Battistoni

Powell

et al. 2015

International Journal of Multiphase Flow

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This paper implements a coupled approach to integrate the internal nozzle flow and the ensuing fuel spray using a Volume-of-Fluid (VOF) method in the finite-volume framework. A VOF method is used to model the internal nozzle two-phase flow with a cavitation description closed by the homogeneous relaxation model of Bilicki and Kestin (1990). An Eulerian single velocity field approach by Vallet et al. (2001) is implemented for near-nozzle spray modeling. This Eulerian approach considers the liquid and gas phases as a complex mixture with a highly variable density to describe near nozzle dense sprays. The liquid mass fraction is transported with a model for the turbulent liquid diffusion flux into the gas. Fully-coupled nozzle flow and spray simulations are performed in three dimensions and validated against the x-ray radiography measurements of Kastengren et al. (2014) for a diesel fuel surrogate. A standard k − ǫ Reynolds Averaged Navier Stokes based turbulence model is used in this study and the influence of model constants is evaluated. First, the grid convergence study is performed. The effect of grid size is also evaluated by comparing the fuel distribution against experimental data. Finally, the fuel distribution predicted by the coupled Eulerian approach is compared against that by Lagrangian-Eulerian spray model along with experimental data. The coupled Eulerian approach provides a unique way of coupling the nozzle flow and sprays so that the effects of in-nozzle flow can be directly realized on the fuel spray. Both experiment and numerical simulations show noncavitation occurring for this injector with convergent nozzle geometry. The study shows that the Eulerian approach has advantages over near-field dense spray distributions.

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“…As pictured at figure 2.17(a) this model disregards parcel direction. This methodology has a strong mesh and time step dependence which can be resolved with adaptive mesh refinements 52 [HS06] …”

Section: Collision and Coalescencementioning

confidence: 99%

Agent-supported simulation environment for intelligent manufacturing and warehouse management systems

Ruiz

Giret

Botti

et al. 2011

International Journal of Production Research

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The main objective of this PhD thesis is the study of Diesel sprays under evaporative conditions by means of Large Eddy Simulations (LES) techniques. This study has been performed implementing a precise, low-demanding LES model in the free, full-purpose Computational Fluid Dynamics (CFD) code OpenFOAM.The starting point was a careful and exhaustive review of the physical processes involved in sprays. An emphasis in CFD methodology, particularly for LES methods, was essential for the thesis, as we were able to find the possible problems and limitations of our approximation. Moreover, as the most widely used techniques for the industrial simulation of sprays are based on the Reynolds-Averaged Navier-Stokes models, we have highlighted the many advantages of LES modeling. As the latter are, by definition, more computationally expensive than RANS, we made an optimal configuration that, while it is able to recover accurately the experimental results, its characteristic time is in the same order of magnitude that RANS ones. As applicability is a must in this thesis, we use the surname "Engineering" LES.One of the key points of the thesis has been the correct configuration of the flow turbulent conditions on the inlet. In order to get accurate results, the turbulent structures coming from this inlet need to be time-and spacecoherent. An adequate calibration of this conditions is needed to perform any spray simulation.Last but not least, all the simulations performed where validated against experiments, obtaining a very good agreement even close to the nozzle. vi ResumenEl objetivo principal de esta tesis es el estudio del modelado numérico de chorros diesel evaporativos mediante la técnica de la simulación de grandes remolinos (LES por sus siglas en inglés). Este estudio se ha realizado mediante la implementación de un modelo LES de altas prestaciones y poco consumo informático en el código libre de dinámica de fluidos computacional (CFD) OpenFOAM.El trabajo de esta tesis ha partido de una revisión exhaustiva de los procesos físicos que tienen lugar en el chorro desde la perspectiva del modelado CFD en general y LES en particular. Esta revisión nos ha permitido identificar los problemas y limitaciones de nuestro planteamiento. Además, dado que la principal técnica CFD usada para el modelado de chorro diesel en procesos industriales son los modelos basados en las ecuaciones promediadas de Reynolds (RANS), se ha incidido en la tesis sobre las ventajas del modelado LES. Dado que estas técnicas son inherentemente más caras que los métodos RANS, se ha hecho hincapié en conseguir una configuraciónóptima que, siendo lo más fiel posible a los resultados experimentales, esté cercana a los tiempos propios de las técnicas RANS. Entendiendo que se quiere hacerénfasis en la aplicabilidad del modelo, se habla de "Engineering" LES.Uno de los puntos claves de la tesis es la adecuada configuración de las condiciones de contorno turbulentas a la entrada de la tobera, que necesitan ser coherentes tanto en espacio como en tiempo. L...

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Adaptive collision meshing and satellite droplet formation in spray simulations

Cited by 43 publications

References 29 publications

Eulerian CFD Modeling of Coupled Nozzle Flow and Spray with Validation Against X-Ray Radiography Data

Eulerian CFD Modeling of Coupled Nozzle Flow and Spray with Validation Against X-Ray Radiography Data

An Eulerian CFD model and X-ray radiography for coupled nozzle flow and spray in internal combustion engines

Agent-supported simulation environment for intelligent manufacturing and warehouse management systems

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