The Fully Lagrangian Approach to the Analysis of Particle/Droplet Dynamics: Implementation Into Ansys Fluent and Application to Gasoline Sprays

Zaripov, Timur; Gilfanov, A. K.; Begg, Steven; Rybdylova, Oyuna; Sazhin, Sergei; Heikal, Morgan

doi:10.1615/atomizspr.2017019354

Cited by 19 publications

(21 citation statements)

References 16 publications

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“…The preliminary results of the application of the new code to the analysis of sprays in gasoline engine-like conditions are shown in Figure 8. The results presented in this figure agree with the results of experimental observations of these sprays [5]. Depending on the distance from the orifice, the computational mesh is refined 2 to 3 times at a sector around the spray, 3 to 4 times at areas of high strain rate and 4 to 5 times for cells that contain droplets.…”

Section: Application To Gasoline Fuel Spraysupporting

confidence: 84%

“…Measurements of the spray shape (geometry and thickness of plume) and its droplet size and velocity distributions were carried out using high-speed photography and Phase Doppler Anemometry, respectively. The experimental set-up and measurement procedure have been described in [5]. The fuel used in our analysis is iso-octane injected at a pressure of 100 bar for a duration of 1 msec.…”

Section: Application To Gasoline Fuel Spraymentioning

confidence: 99%

“…Although various approaches to modelling this coupling have been suggested [1,2,3,4,5], this problem is far from being solved. The main focus of this paper is on the description of the new approach to this coupling and the application of this approach to modelling realistic sprays in gasoline-engine-like conditions.…”

Section: Introductionmentioning

confidence: 99%

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A new approach to modelling the two way coupling for momentum transfer in a hollow-cone spray

Papoutsakis

Sazhin

Begg

et al. 2017

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

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A new approach to modelling the interaction between droplets and the carrier phase is suggested. The new model is applied to the analysis of a spray injected into a chamber of quiescent air, using an Eulerian-Lagrangian approach. The conservative formulation of the equations for mass, momentum and energy transport is used for the analysis of the carrier phase. The dispersed phase is modelled using the Lagrangian approach with droplets represented by individual parcels. The implementation of the Discontinuous Galerkin method (ForestDG), based on a topological representation of the computational mesh by a hierarchical structure consisting of oct-quad-and binary trees, is used in our analysis. Adaptive mesh refinement (h-refinement) enables us to increase the spatial resolution for the computational mesh in the vicinity of the points of interest such as interfaces, geometrical features, or flow discontinuities. The local increase in the expansion order (p-refinement) at areas of high strain rates or vorticity magnitude results in an increase of the order of the accuracy of discretisation of shear layers and vortices. The initial domain consists of a graph of unitarian-trees representing hexahedral, prismatic and tetrahedral elements. The ancestral elements of the mesh can be split into self-similar elements allowing each tree to grow branches to an arbitrary level of refinement. The connectivity of the elements, their genealogy and their partitioning are described by linked lists of pointers. These are attached to the tree data structure which facilitates the on-the-fly splitting, merging and repartitioning of the computational mesh by rearranging the links of each node of the tree. This enables us to refine the computational mesh in the vicinity of the droplet parcels aiming to accurately resolve the coupling between the two phases. KeywordsDroplets, Sprays, Vortex Rings, Discontinuous Galerkin, Adaptive Mesh Refinement. IntroductionThe need to accurately model the interaction between droplets and carrier phase (coupling) in various engineering applications is well known [1]. Although various approaches to modelling this coupling have been suggested [1,2,3,4,5], this problem is far from being solved. The main focus of this paper is on the description of the new approach to this coupling and the application of this approach to modelling realistic sprays in gasoline-engine-like conditions. This new approach is based on the application of the adaptive mesh refinement in the vicinity of the droplet parcels. The Discontinuous Galerkin (DG) method [6,7,8,9] is used for solving the equations for the carrier phase. The latter method combines high order accuracy with the ability to handle complex geometries described by hybrid unstructured meshes by incorporating a minimal computational stencil. However, the computational efficiency of this method (alongside the spectral volume [8,10] and spectral difference [8,11,12] methods is generally believed to be inferior to more commonly used methods as the Finite Differenc...

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Section: Application To Gasoline Fuel Spraysupporting

confidence: 84%

Section: Application To Gasoline Fuel Spraymentioning

confidence: 99%

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A new approach to modelling the two way coupling for momentum transfer in a hollow-cone spray

Papoutsakis

Sazhin

Begg

et al. 2017

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

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show abstract

“…An Eulerian approach is typically used for modelling of such flows [84]. Hybrid Lagrangian-Eulerian approaches [83,87,88,89,90], however, offer more realistic modelling of the dispersed continuum which can be multi-valued. The fuel used in our analysis is iso-octane, injected at a pressure of 100 bar for a duration of T = 1 ms. Injection mass flow rateṁ (measured experimentally using a rate tube) increased linearly from zero up to a maximum value oḟ m 0 = 30 g/s in 0.1 ms. During the following 0.8 ms the mass flow rate remains constant and decreases to zero during the last 0.1 ms.…”

Section: Application To a Gasoline Fuel Spraymentioning

confidence: 99%

“…Measurements of the spray shape (geometry and thickness of plume) and droplet size and velocity distributions were carried out using high-speed photography and Phase Doppler Anemometry, respectively. The experimental set-up and measurement procedure are described in [90]. The computational mesh is refined 2 times in the vicinity of the spray, 3 to 4 times in areas of high vorticity and 4 times in the cells that contain droplets.…”

Section: Application To a Gasoline Fuel Spraymentioning

confidence: 99%

An efficient Adaptive Mesh Refinement (AMR) algorithm for the Discontinuous Galerkin method: Applications for the computation of compressible two-phase flows

Papoutsakis

Sazhin

Begg

et al. 2018

Journal of Computational Physics

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We present an Adaptive Mesh Refinement (AMR) method suitable for hybrid unstructured meshes that allows for local refinement and de-refinement of the computational grid during the evolution of the flow. The adaptive implementation of the Discontinuous Galerkin (DG) method introduced in this work (ForestDG) is based on a topological representation of the computational mesh by a hierarchical structure consisting of oct-quad-and binary trees. Adaptive mesh refinement (h-refinement) enables us to increase the spatial resolution of the computational mesh in the vicinity of the points of interest such as interfaces, geometrical features, or flow discontinuities. The local increase in the expansion order (p-refinement) at areas of high strain rates or vorticity magnitude results in an increase of the order of accuracy in the region of shear layers and vortices. A graph of unitarian-trees, representing hexahedral, prismatic and tetrahedral elements is used for the representation of the initial domain. The ancestral elements of the mesh can be split into self-similar elements allowing each tree to grow branches to an arbitrary level of refinement. The connectivity of the elements, their genealogy and their partitioning are described by linked lists of pointers. An explicit calculation of these relations, presented in this paper, facilitates the on-the-fly splitting, merging and repartitioning of the computational mesh by rearranging the links of each node of the tree with a minimal computational overhead. The modal basis used in the DG implementation facilitates the mapping of the fluxes across the non conformal faces. The AMR methodology is presented and assessed using a series of inviscid and viscous test cases. Also, the AMR methodology is used for the modelling of the interaction between droplets and the carrier phase in a two-phase flow. This approach is applied to the analysis of a spray injected into a chamber of quiescent air, using the Eulerian-Lagrangian approach. This enables us to refine the computational mesh in the vicinity of the droplet parcels and accurately resolve the coupling between the two phases.

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Robust interpolation for dispersed gas‐droplet flows using statistical learning with the fully Lagrangian approach

2023

Numerical Methods in Fluids

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SummaryA novel methodology is presented for reconstructing the Eulerian number density field of dispersed gas‐droplet flows modelled using the fully Lagrangian approach (FLA). In this work, the nonparametric framework of kernel regression is used to accumulate the FLA number density contributions of individual droplets in accordance with the spatial structure of the dispersed phase. The high variation which is observed in the droplet number density field for unsteady flows is accounted for by using the Eulerian‐Lagrangian transformation tensor, which is central to the FLA, to specify the size and shape of the kernel associated with each droplet. This procedure enables a high level of structural detail to be retained, and it is demonstrated that far fewer droplets have to be tracked in order to reconstruct a faithful Eulerian representation of the dispersed phase. Furthermore, the kernel regression procedure is easily extended to higher dimensions, and inclusion of the droplet radius within the phase space description using the generalised fully Lagrangian approach (gFLA) additionally enables statistics of the droplet size distribution to be determined for polydisperse flows. The developed methodology is applied to a range of one‐dimensional and two‐dimensional steady‐state and transient flows, for both monodisperse and polydisperse droplets, and it is shown that kernel regression performs well across this variety of cases. A comparison is made against conventional direct trajectory methods to determine the saving in computational expense which can be gained, and it is found that times fewer droplet realisations are needed to reconstruct a qualitatively similar representation of the number density field.

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The Fully Lagrangian Approach to the Analysis of Particle/Droplet Dynamics: Implementation Into Ansys Fluent and Application to Gasoline Sprays

Cited by 19 publications

References 16 publications

A new approach to modelling the two way coupling for momentum transfer in a hollow-cone spray

A new approach to modelling the two way coupling for momentum transfer in a hollow-cone spray

An efficient Adaptive Mesh Refinement (AMR) algorithm for the Discontinuous Galerkin method: Applications for the computation of compressible two-phase flows

Robust interpolation for dispersed gas‐droplet flows using statistical learning with the fully Lagrangian approach

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