Experimental investigation of dynamic binary collision of ethanol droplets – a model for droplet coalescence and bouncing

Estrade, J.-P.; Carentz, Hervé; Lavergne, G.; Biscos, Y.

doi:10.1016/s0142-727x(99)00036-3

Cited by 169 publications

(171 citation statements)

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“…The variation of the bouncing boundary in dependence of the size ratio is shown in Figure 2 a). With decreasing size ratio = dS/dL the boundary line is slightly shifted upward and to the left in accordance with the measurements presented by Estrade et al (1999). However, the question is whether the proposed correlation is also valid for small size ratios which are likely to be found in spraying systems as will be shown below.…”

Section: Theoretical Boundary Linessupporting

confidence: 86%

“…This point was identified by Sommerfeld and Kuschel (2016) and Sommerfeld (2016) to have a characteristic movement with increasing viscosity. The third characteristic point results from the lower boundary of bouncing intercepting with the horizontal axis (Estrade et al 1999). In some studies and for some liquids also a coalescence region for very low We over a wide range of impact parameters was found (Qian and Law 1997, Chen 2007and Huang and Pan 2015, which however will not considered here for the moment.…”

Section: Characteristic Points In the Collision Mapsmentioning

confidence: 93%

“…Based on an energy balance Estrade et al (1999) developed the lower boundary of bouncing. For that it was assumed that the initial droplet kinetic energy of the deformation region does not exceed the surface energy difference to produce a certain deformation.…”

Section: Theoretical Boundary Linesmentioning

confidence: 99%

“…Hence the shape factor should be depending on liquid dynamic viscosity. The correlation of Estrade et al (1999) is given by:…”

Section: Theoretical Boundary Linesmentioning

confidence: 99%

“…For the upper boundary of reflexive separation the shifted Ashgriz and Poo (1990) correlation is used. It was however so far not possible to predict the lower bouncing boundary through the Estrade et al (1999) boundary line correctly. The proposed boundary-line models were validated for various liquid, however still considering only a size ratio of one.…”

Section: Introductionmentioning

confidence: 99%

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Numerical analysis of sprays with an advanced collision model

Sommerfeld

Laı́n

2017

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

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Modelling of collisions between liquid droplets in the frame of a Lagrangian spray simulation has still many open issues, especially when considering higher viscous droplets and if colliding droplets have a large size difference. A generalisation of the collision maps is attempted based on the behaviour of characteristic points, namely the triple point where bouncing, coalescence and stretching separation coincide and the critical Weber-number where reflexive separation first occurs in head-on collisions. This is done by correlating experimental data with respect to the Capillary number with the Ohnesorge-number for the triple point and the critical Weber-number is also well described by a correlation the Ohnesorge-number. Based on these results the boundary line between stretching separation and coalescence is found by adapting the Jiang et al. (1992) correlation. For the upper boundary of reflexive separation the shifted Ashgriz and Poo (1990) correlation is used. It was however so far not possible to predict the lower bouncing boundary through the Estrade et al. (1999) boundary line correctly. The proposed boundary-line models were validated for various liquid, however still considering only a size ratio of one. With the developed three-line boundary model Euler/Lagrange numerical calculations for a simple spray system were conducted and the droplet collisions were analysed with respect to their occurrence. Droplet collision modelling is performed on the basis of the stochastic droplet collision model, also considering the influence of impact efficiency, which so far was neglected for most spray simulations. The comparison with measurements showed reasonable good agreement for all properties. KeywordsDroplet collisions, stochastic collision model, impact efficiency, collision outcomes, Euler/Lagrange calculations, spray simulations. IntroductionIn numerous technical and industrial spraying systems higher viscous liquids, suspensions or solutions are being atomised. Examples are liquid fuels (including bio-fluids) in combustion systems, liquid melts or other mineral melts in the field of materiel science and spray drying of foodstuff or pharmaceutical materials. Therefore, in a numerical calculation of such spraying systems, mostly done with an Euler/Lagrange approach, the resulting different liquid properties have to be accounted for. Here the focus is related to droplet collision modelling. Hence, established droplet collision models have to be generalized regarding liquid properties, mainly viscosity and surface tension. Since colliding droplets may have considerable different size also the droplet size ratio is an important parameter to be considered in droplet collision modelling. In order to model droplet collisions in the frame of the Lagrangian droplet parcel concept, where only pointmasses are tracked, applied to spraying systems several elementary processes have to be considered (Sommerfeld and Kuschel 2016). The first step is the detection of possible collisions between two droplets. In orde...

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Section: Theoretical Boundary Linessupporting

confidence: 86%

Section: Characteristic Points In the Collision Mapsmentioning

confidence: 93%

Section: Theoretical Boundary Linesmentioning

confidence: 99%

“…Hence the shape factor should be depending on liquid dynamic viscosity. The correlation of Estrade et al (1999) is given by:…”

Section: Theoretical Boundary Linesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Numerical analysis of sprays with an advanced collision model

Sommerfeld

Laı́n

2017

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

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Droplet collision of hypergolic propellants

He,

Zhang

2024

Droplet

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In the present mini‐review, droplet impacting on a liquid pool, jet impingement, and binary droplet collision of nonreacting liquids are first summarized in terms of basic phenomena and the corresponding nondimensional parameters. Then, two representative hypergolic bipropellant systems, a hypergolic fuel of N,N,N′,N′‐tetramethylethylenediamine (TMEDA) and an oxidizer of white fuming nitric acid (WFNA) and a monoethanolamine‐based fuel (MEA‐NaBH4) and a high‐density hydrogen peroxide (H2O2), are discussed in detail to unveil the rich underlying physics such as liquid‐phase reaction, heat transfer, phase change, and gas‐phase reaction. This review focuses on quantifying and interpreting the parametric dependence of the gas‐phase ignition induced by droplet collision of liquid hypergolic propellants. The advances in droplet collision of hypergolic propellants are important for modeling the real hypergolic impinging‐jet (spray) combustion and for the design optimization of orbit‐maneuver rocket engines.

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Droplet Collision

Brenn

2010

Handbook of Atomization and Sprays

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Experimental investigation of dynamic binary collision of ethanol droplets – a model for droplet coalescence and bouncing

Cited by 169 publications

References 2 publications

Numerical analysis of sprays with an advanced collision model

Numerical analysis of sprays with an advanced collision model

Droplet collision of hypergolic propellants

Droplet Collision

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