Multiple Drop Impact onto a Dry Solid Substrate

Roisman, Ilia V.; Prunet-Foch, B.; Tropea, Cameron; Vignes-Adler, M.

doi:10.1006/jcis.2002.8683

Cited by 103 publications

(64 citation statements)

References 17 publications

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“…[30] However, to the best of our knowledge, nothing similar has been reported in the case of interest to secondary cooling where small drops arrive randomly at the substrate in conditions of high waterimpact density that make difficult the visual observation of the events happening on the substrate. However, knowing the drop diameter and the water-impact flux can give an approximate picture of how an originally dry solid surface may look after being impinged during a short period of time at the start of spraying.…”

Section: Drop Impaction and Arrival Onto A Solid Surfacementioning

confidence: 88%

“…As mentioned widely in the literature, [5][6][7]17,30] for single drops or drops in dilute sprays, the relative importance of the drop kinetic energy to its surface energy, as given by the We zs number, is the major factor influencing its impaction dynamics and its heat-extraction effectiveness. For We zs £ 1, the drops would practically deposit on the surface; at 1 < We zs £ 30, the drops impact in a nonwetting elastic-rebounding mode; at 30 < We zs £ 80, the drops deform plastically, and their rebounding is less intense, and these characteristics are more acute as We zs increases; finally, for We zs > 80, the drops spread in a thin film that breaks into several secondary drops.…”

Section: Drop Impaction and Arrival Onto A Solid Surfacementioning

confidence: 99%

“…The factors that would distinguish interacting from noninteracting drops at the surface would be w, d d , and the speed at which the drops are removed from the surface. Considering the derivation of Toda [30] of the time period, s d , at which consecutive drops fall over the same position onto the substrate, it has been shown elsewhere [28] that the areas in Figure 17 would be completely covered by a water film after this time has elapsed and if the preceding drops are not removed. The rapid flooding of the surface is consistent with the little increase in heat flux that has been observed to occur after w exceeds a certain value.…”

Section: Drop Impaction and Arrival Onto A Solid Surfacementioning

confidence: 99%

See 2 more Smart Citations

The Fluid Dynamics of Secondary Cooling Air-Mist Jets

C.¹,

G.²,

E.³

et al. 2008

Metall Mater Trans B

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For the conditions of thin-slab continuous casting, air-mist secondary cooling occurs in the transition-boiling regime, possibly as a result of an enhanced intermittent contact of highmomentum water drops with the hot metallic surface. The dynamics of the intermittent contact or wetting/dewetting process should be primarily dependent on the drop size, drop impactvelocity and -angle and water-impact flux, which results from the nozzle design and the interaction of the drops with the conveying and entrained air stream. The aim of this article was to develop a model for predicting the last three parameters based on the design and operating characteristics of air-mist nozzles and on experimentally determined drop-size distributions. To do this, the Eulerian fluid-flow field of the air in three dimensions and steady state and the Lagrangian velocities and trajectories of water drops were computed by solving the turbulent Navier-Stokes equation for the air coupled to the motion equation for the water drops. In setting this model, it was particularly important to specify appropriately the air-velocity profile at the nozzle orifice, as well as, the water-flux distribution, and the velocities (magnitude and angle) and exit positions of drops with the different sizes generated, hence special attention was given to these aspects. The computed drop velocities, water-impact flux distributions, and airmist impact-pressure fields compared well with detailed laboratory measurements carried out at ambient temperature. The results indicate that under practical nozzle-operating conditions, the impinging-droplet Weber numbers are high, over most of the water footprint, suggesting that the droplets should establish an intimate contact with the solid surface. However, the associated high mean-droplet fluxes hint that this contact may be obstructed by drop interference at the surface, which would undermine the heat-extraction effectiveness of the impinging mist. The model also points out that a large proportion of fine drops would be prevented by the air-flow pattern from reaching the surface. The numerical analysis of air-mist jets under conditions relevant to secondary cooling had not been addressed before, and it constitutes a first step in an effort to develop a model to describe the dynamic and thermal interaction of dense-drop media with hot metallic surfaces.

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Section: Drop Impaction and Arrival Onto A Solid Surfacementioning

confidence: 88%

Section: Drop Impaction and Arrival Onto A Solid Surfacementioning

confidence: 99%

Section: Drop Impaction and Arrival Onto A Solid Surfacementioning

confidence: 99%

See 1 more Smart Citation

The Fluid Dynamics of Secondary Cooling Air-Mist Jets

C.¹,

G.²,

E.³

et al. 2008

Metall Mater Trans B

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show abstract

“…They are deposition, prompt splash, corona splash, receding breakup, partial rebound and complete rebound. Roisman et al [13] experimentally and theoretically studied the impact of multiple droplets onto a dry substrate by considering the effects of surface tension, wettability, viscosity, gravity and inertia. Tanaka et al [14] performed two-dimensional numerical simulations of collision dynamics of an impacting droplet with a stationary droplet on a solid surface by using a two-phase LBM.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of falling droplets impact on a liquid film: Hybrid lattice Boltzmann simulation

Liu

Zhao

2015

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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“…In actual applications, however, the effects of the inertial force between the coalescing droplets, the hydrophilic property of the surface, and the drop interval between liquid droplets are very important. For the inertiadominant situation, Roisman et al (2002) established a droplet coalescence model corresponding to the case in which the Re and We numbers were high and the interaction between the liquid droplets was small. The results of the model well matched the experimental results.…”

Section: Introductionmentioning

confidence: 99%

On the Dynamic Behavior of a Liquid Droplet Impacting upon a Wall Having Obstacles

Kang

2015

JAFM

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In this paper, the effects of a step edge and a stationary droplet on the dynamic behavior of a droplet impacting upon a wall are experimentally studied. The main parameters were the distance from the step edge to the center of the impacting droplet and the center-to-center distance between the stationary and impacting droplets. Photographic images showed the coalescence dynamics, shape evolution and contact line movement of the impacting droplet. The spread length is presented for the step edge and two coalescing droplets. The droplets exhibited much different dynamic behavior depending on the location of the step edge. The momentum of the impacting droplet was better transferred to the stationary droplet as the center-to-center distance between the two droplets was reduced, resulting in more spreading of the coalescing droplet. Keywords

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Multiple Drop Impact onto a Dry Solid Substrate

Cited by 103 publications

References 17 publications

The Fluid Dynamics of Secondary Cooling Air-Mist Jets

The Fluid Dynamics of Secondary Cooling Air-Mist Jets

Dynamics of falling droplets impact on a liquid film: Hybrid lattice Boltzmann simulation

On the Dynamic Behavior of a Liquid Droplet Impacting upon a Wall Having Obstacles

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