A Combined Fully Lagrangian Approach to Mesh-Free Modelling of Transient Two-Phase Flows

Лебедева, Н. А.; Осипцов, А. Н.; Sazhin, Sergei

doi:10.1615/atomizspr.2013006269

Cited by 18 publications

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“…A combined meshless method for modelling gas-particle flows was considered by Chen and Marshall (1999); Walther and Koumoutsakos (2001). Lebedeva et al (2013) proposed a method combining the viscous-vortex method for the carrier phase and the Fully Lagrangian approach (Osiptsov, 2000) for particles. This method combines the 10 advantages of both the viscous-vortex and the Fully Lagrangian approaches.…”

Section: Introductionmentioning

confidence: 99%

“…However, in many engineering applications, including automotive applications (Sazhina et al, 2000;Sazhin et al, 2014), the effects of heat and mass transfer are significant. The objective of the present study is to generalise the approach described in Lebedeva et al (2013) to take into 20 account some of these effects. The phase transitions on the droplet surface are described using a simple model developed in Osiptsov and Shapiro (1993); Wang and Osiptsov (2002).…”

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confidence: 99%

“…The droplet trajectories and the fields of droplet velocities, temperature, and sizes are calculated using the Lagrangian approach, which makes it possible to calculate correctly regions with intersecting droplet trajectories and to simulate correctly the mixing of droplets in the carrier phase 60 and the spatial variation of droplet sizes due to evaporation. As shown in Lebedeva et al (2013), the appearance of the regions with crossing trajectories is typical of impulse jet flows, and standard Eulerian approaches fail to describe correctly the distribution of droplet parameters in these regions.…”

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confidence: 99%

“…The accuracy of calculations depends on the choice of the form of the cut-off function ζ ε i (r). In contrast to Lebedeva et al (2013), where a very simple cut-off function was used, we used the 4th order cut-off function, recommended in Cottet and Koumoutsakos (2000):…”

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A combined viscous-vortex, thermal-blob and Lagrangian method for non-isothermal, two-phase flow modelling

Rybdylova

Осипцов

Sazhin

et al. 2016

International Journal of Heat and Fluid Flow

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A meshless method for modelling of 2D transient, non-isothermal, gas-droplet flows with phase transitions, based on a combination of the viscous-vortex and thermal-blob methods for the carrier phase with the Lagrangian approach for the dispersed phase, is developed. The one-way coupled, two-fluid approach is used in the analysis. The method makes it possible to avoid the 'remeshing' procedure (recalculation of flow parameters from Eulerian to Lagrangian grids) and reduces the problem to the solution of three systems of ordinary differential equations, describing the motion of viscous-vortex blobs, thermal blobs, and evaporating droplets. The gas velocity field is restored using the Biot-Savart integral. The numerical algorithm is verified against the analytical solution for a non-isothermal Lamb vortex and some asymptotic results known in the literature. The method is applied to modelling of an impulse two-phase cold jet injected into a quiescent hot gas, taking into account droplet evaporation. Various flow patterns are obtained in the calculations, depending on the initial droplet size: (i) low-inertia droplets, evaporating at a higher rate, form ring-like structures and are accumulated only behind the vortex pair; (ii) large droplets move closer to the jet axis, with their sizes remaining almost unchanged; and (iii) intermediate-size droplets are accumulated in a curved band whose ends trail in the periphery behind the head * Corresponding author Email address: O.Rybdylova@brighton.ac.uk (O. Rybdylova)Preprint submitted to International Journal of Heat and Fluid Flow October 28, 2015 of the cloud, with larger droplets being collected at the front of the two-phase region.

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Section: Introductionmentioning

confidence: 99%

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A combined viscous-vortex, thermal-blob and Lagrangian method for non-isothermal, two-phase flow modelling

Rybdylova

Осипцов

Sazhin

et al. 2016

International Journal of Heat and Fluid Flow

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“…These methods make it possible to develop fully meshless methods for two-phase flows as well. In [2] a method combining the viscous-vortex and the Fully Lagrangian [3,4] approaches was suggested to simulate particle-laden flows for which accurate calculations of the particle number density are required. In the present study, the viscous-vortex method is developed to model 2D transient, non-isothermal, 'gas -droplet' flows.…”

Section: Introductionmentioning

confidence: 99%

A fully meshless method for ‘gas – evaporating droplet’ flow modelling

Rybdylova

Осипцов

Sazhin

et al. 2015

Proc Appl Math and Mech

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A meshless method for modelling two-phase flows with phase transition is described. The method is based on consideration of three systems: viscous-vortex blobs, thermal-blobs and droplets; and can be applied for numerical simulation of 2D nonisothermal flows of 'gas-evaporating droplets' in the framework of the one-way coupled two-fluid approach. The carrier phase is viscous incompressible gas. The dispersed phase is presented by a cloud of identical spherical droplets, and, due to evaporation, the radius and mass of droplets are time dependent. The carrier phase parameters are calculated using the viscous-vortex and thermal-blob method; the dispersed phase parameters are calculated using the Lagrangian approach. Two applications have been considered: (i) a standard benchmark -Lamb vortex; (ii) a cold spray injected into a hot quiescent gas. In the latter problem three cases corresponding to three droplet sizes were investigated. The smallest droplets (of the three cases considered) are more readily entrained by the carrier phase and form ring-like structures; the flow shows better mixing. Larger droplets evaporate less intensively. The medium sized droplets collect into two narrow bands stretched along the jet axis. The largest droplets form a two-phase jet, which remains close to the jet axis.

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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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A Combined Fully Lagrangian Approach to Mesh-Free Modelling of Transient Two-Phase Flows

Cited by 18 publications

References 0 publications

A combined viscous-vortex, thermal-blob and Lagrangian method for non-isothermal, two-phase flow modelling

A combined viscous-vortex, thermal-blob and Lagrangian method for non-isothermal, two-phase flow modelling

A fully meshless method for ‘gas – evaporating droplet’ flow modelling

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

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