Towards an interpretation of the scale diffusivity in liquid atomization process: An experimental approach

Dumouchel, Christophe; Ménard, Thibaut; Aniszewski, Wojciech

doi:10.1016/j.physa.2015.07.008

Cited by 7 publications

(13 citation statements)

References 16 publications

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“…The presentation is restricted to the elements relevant for the present work. (More details are available in [6][7][8][9].) The 2D multi-scale description of a liquid system consists in…”

Section: D Multi-scale Descriptionmentioning

confidence: 99%

“…Quite often this detection is made easier by imposing the perturbation frequency that annihilates the temporal and spatial variabilities of the jet behavior [5]. This constraint may be skipped by using a multi-scale tool such as the one recently introduced to describe and analyze timedependent fluid domains in atomization processes [6][7][8]. In this technique, any fluid region delimited by an interface is described by a scale distribution that is measured as a function of time.…”

Section: Introductionmentioning

confidence: 99%

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Multi-scale analysis of a viscoelastic liquid jet

Tirel

Renoult

Dumouchel

et al. 2017

Journal of Non-Newtonian Fluid Mechanics

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A multi-scale analyzing tool is now available to investigate the temporal evolution of two phase flows such as liquid systems experiencing an atomization process. Thanks to its multi-scale and global nature, it allows identifying all dynamics simultaneously involved in the process with no restriction of the liquid system shape. In the present work this multi-scale tool is applied on 2D visualizations of free falling jets of a low-viscosity viscoelastic solution. The jets are produced from a cylindrical discharge orifice and the liquid is a very dilute polymer solution containing 5 PPM of Poly(ethylene oxide). High spatial resolution images of the free falling jets are performed as a function of the velocity and at several distances from the discharge orifice. For every operating condition, the liquid jet remains cylindrical first, then shows the development of a sinusoidal perturbation and finally adopts a beads-on-a-string pattern before breakup occurs. The multi-scale analysis is performed on a high number of images and at several spatial positions in order to return statistical and temporal information, respectively. The results of this analysis show that during the sinusoidal perturbation stage, the large-scale region follows an exponential increase as predicted by the linear stability theory and during the beads-on-a-string

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“…The presentation is restricted to the elements relevant for the present work. (More details are available in [6][7][8][9].) The 2D multi-scale description of a liquid system consists in…”

Section: D Multi-scale Descriptionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Multi-scale analysis of a viscoelastic liquid jet

Tirel

Renoult

Dumouchel

et al. 2017

Journal of Non-Newtonian Fluid Mechanics

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“…A similar idea has been also explored by Dumouchel et al (2015Dumouchel et al ( , 2017 with the concept of scale distribution, E 3 (d). The definition of this function for a given object (for instance a droplet) is based on the total object volume V 0 and the volume V (d) defined by all points at a distance d or greater to the object surface.…”

Section: An Extended Definition Of the Drop Size Distributionmentioning

confidence: 99%

Where does the droplet size distribution come from?

Canu

Puggelli

Essadki

et al. 2018

International Journal of Multiphase Flow

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This study employs DNS of two-phase flows to enhance primary atomization understanding and modeling to be used in numerical simulation in RANS or LES framework. In particular, the work has been aimed at improving the information on the liquid-gas interface evolution for modeling approaches, such as the Eulerian-Lagrangian Spray Atomization (ELSA) framework. Even though this approach has been already successfully employed to describe the complete liquid atomization process from the primary region to the dilute spray, improvements are still expected on the derivation of the drop size distribution (DSD). The main aim of the present work is the introduction of a new framework to achieve a continuous description of the DSD formation during the atomization process. The attention is here focused on the extraction from DNS data of the behavior of geometrical variable of the liquid-gas interface, such as the mean (H) and Gauss (G) surface curvatures. The use of a Surface Curvature Distribution is also proposed and studied. A Rayleigh-Plateau instability along a column of liquid and a droplet collision case are first of all considered to analyze and to verify the capabilities of the code to correctly predicting the curvature distributions. A statistical analysis

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“…However, this distribution can be clearly identified on a given geometric object and in particular for a spherical droplet. Indeed, this idea has been explored by Dumouchel and co-workers [12,13] with the concept of scale distribution, 3 ( ). The definition of this function for a given object (for instance a droplet) is based on the total object volume 0 and the volume ( ) defined by all points at a distance or greater to the object surface.…”

Section: An Extended Definition Of the Drop Size Distributionmentioning

confidence: 99%

Where does the drop size distribution come from?

Canu

Dumouchel

Duret

et al. 2017

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

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This study employs DNS of two-phase flows to enhance primary atomization understanding and modelling to be used in numerical simulation in RANS or LES framework. In particular, the work has been aimed at improving the information on the liquid-gas interface evolution available inside the Eulerian-Lagrangian Spray Atomization (ELSA) framework. Even though this approach has been successful to describe the complete liquid atomization process from the primary region to the dilute spray, major improvements are expected on the establishment of the drop size distribution (DSD). Indeed, the DSD is easily defined once the spray is formed, but its appearance and even the mathematical framework to describe its creation during the initial breakup of the continuous liquid phase in a set of individual liquid parcels is missing. This is the main aim of the present work to review proposals to achieve a continuous description of the DSD formation during the atomization process. The attention is here focused on the extraction from DNS data of the behaviour of geometrical variable of the liquidgas interface, such as the mean and Gauss surface curvatures. A DNS database on curvature evolution has been generated. A Rayleigh-Plateau instability along a column of liquid is considered to analyse and to verify the capabilities of the code in correctly predicting the curvature distribution. A statistical analysis on the curvatures data, in terms of probability density function, was performed in order to determine the physical parameters that control the curvatures on this test case. Two different methods are presented to compute the curvature distribution and in addition, the probability to be at a given distance of the interface is studied. This approach finally links the new tools proposed to follow the formation of the spray with the pioneering work done on scale distribution analysis. Birth of drop size distributionA standard output expected from any atomization model or theory is the drop size distribution (DSD). There are several definitions of this function. Most generally, it is ( ) in such way that ( ′ )is the number of droplet per unit of volume with a diameter ∈ [ ′ , ′ + [ . In this case, it is the number diameter distribution (NDD) and it may be also normalized to define a probability density function ( ). The function ( ) requires the possibility to count the number of droplets. Thus, it is necessary to separate the liquid phase in a set of discrete elements. Usual atomization starts with a continuous liquid flow (for instance a liquid jet) and during the atomization process the splitting of the continuous liquid phase occurs. This phase of the atomization process can be associated to the so-called primary breakup. Once it is created, for fixed external conditions and generally considering the whole spray, the NDD may evolve towards an asymptotic state, for which numerous theoretical and experimental works are reported in the literature [1]. To address more complex situations or to determine its function in space an...

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Towards an interpretation of the scale diffusivity in liquid atomization process: An experimental approach

Cited by 7 publications

References 16 publications

Multi-scale analysis of a viscoelastic liquid jet

Multi-scale analysis of a viscoelastic liquid jet

Where does the droplet size distribution come from?

Where does the drop size distribution come from?

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