An experimental study of droplet-particle collisions

Pawar, SK Sandip; Henrikson, Filip; Finotello, Giulia; Padding, JT Johan; Deen, NG Niels; Jongsma, Alfred; Innings, Fredrik; Kuipers, J.A.M.

doi:10.1016/j.powtec.2016.06.005

Cited by 82 publications

(73 citation statements)

References 13 publications

(17 reference statements)

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“…The contact angle between distilled water and glass was measured between 59 • and 67 • . This is somewhat lower than the 70 • -80 • range for water on glass contact angle reported by Pawar et al (2016). Three particle diameters, D 0 , were considered, namely, 500 µm, 1000 µm, and 2000 µm, making the particle greater than the diameter of the colliding droplet.…”

Section: Experimental Arrangement and Methodsmentioning

confidence: 89%

“…Also, since research of droplet-particle collisions is generally limited to smooth particles, comparison of the results obtained here with the results of previous investigations [for example, Liang et al (2014) considered particles with surface roughness less than 50 nm] is made possible. Finally, even for investigations with ultimate interest in spray drying applications, smooth glass particles have also been used in the past (Pawar et al, 2016).…”

Section: Experimental Arrangement and Methodsmentioning

confidence: 99%

“…The ratio of the area covered by the liquid film was shown to increase by decreasing the droplet/particle curvature ratio, while the Weber number was found to have only a minor effect. Pawar et al (2016) considered the collisions of droplets with a diameter of 2.9 mm with particles with diameters of 2.5 mm or 4.0 mm, respectively, in the Weber number range between 0.34 and 52. The collision outcomes were classified as either agglomeration, where the whole particle being engulfed by the droplet, or stretching separation, where only part of the liquid droplet attaches to the particle after the collision.…”

Section: Introductionmentioning

confidence: 99%

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Collisions of droplets on spherical particles

Charalampous

Hardalupas

2017

Physics of Fluids

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Head-on collisions between droplets and spherical particles are examined for water droplets in the diameter range between 170 μm and 280 μm and spherical particles in the diameter range between 500 μm and 2000 μm. The droplet velocities range between 6 m/s and 11 m/s, while the spherical particles are fixed in space. The Weber and Ohnesorge numbers and ratio of droplet to particle diameter were between 92 < We < 1015, 0.0070 < Oh < 0.0089, and 0.09 < Ω < 0.55, respectively. The droplet-particle collisions are first quantified in terms of the outcome. In addition to the conventional deposition and splashing regimes, a regime is observed in the intermediate region, where the droplet forms a stable crown, which does not breakup but propagates along the particle surface and passes around the particle. This regime is prevalent when the droplets collide on small particles. The characteristics of the collision at the onset of rim instability are also described in terms of the location of the film on the particle surface and the orientation and length of the ejected crown. Proper orthogonal decomposition identified that the first 2 modes are enough to capture the overall morphology of the crown at the splashing threshold.

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Section: Experimental Arrangement and Methodsmentioning

confidence: 89%

Section: Experimental Arrangement and Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Collisions of droplets on spherical particles

Charalampous

Hardalupas

2017

Physics of Fluids

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“…In contrast to the drop-drop collisions [13][14][15][16][17][18], here we distinguished two regimes. In the first regime, the first drop spreads and all the successively impinging drops merge into a liquid layer on the surface.…”

Section: Of 19mentioning

confidence: 83%

“…The second regime involves a fine aerosol generated by the drop impact on the wall. When drops collide with each other, four regimes are identified [13][14][15][16][17][18], namely, coalescence, rebound, separation, and breakup. Rebound means that drops approach each other and then move apart without immediate contact because the kinetic energy is not enough for drops to pass across the gas-vapor layer between them.…”

Section: Of 19mentioning

confidence: 99%

The Impact of Single- and Multicomponent Liquid Drops on a Heated Wall: Child Droplets

et al. 2020

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This paper presents the experimental research into the impingement of single-and multicomponent liquid drops on a solid wall. We focus on studying the conditions and characteristics of two impact scenarios: rebound and breakup. We performed a comprehensive analysis of the effect of a group of factors on the drop transformation and fragmentation characteristics. These factors include the drop velocity and size, Weber number, impinging angle, wall temperature, thermophysical properties of the wall material, surface roughness, hydrophilic and hydrophobic behavior of the surface, homogeneity and inhomogeneity of the drop composition, as well as viscosity and surface tension of the liquid. We compared the outcomes of one, two, and three drops with the same total volume on a wall. Histograms were plotted of the number and size distribution of the emerging secondary droplets. The results include the critical conditions for the intense breakup of drops. Such factors as wall heating, its roughness, impinging angle, drop size and velocity affected the breakup conditions most notably. The variation of a group of these factors could provide a 2-25-fold increase in the liquid surface area as a result of the impact. up after impinging on the surface. If We < 30, drop rebound took place. At 50 < We < 80, the drop spread over the surface and the resulting lamella disintegrated to form secondary droplets. Moreover, Liang and Mudawar [1] demonstrated the snapshots illustrating details of the drop spreading over a heated surface.The contact time of a drop with a surface also depends on its hydrophobicity. For example, Tang et al. [5] studied the behavior of a water drop when interacting with superhydrophobic surfaces in the presence of a cold airflow. Experimental studies were carried out at an ambient temperature ranging from −10 • C to 30 • C to investigate the effect of the airflow on a water drop. In the case of superhydrophobic surfaces, a decrease in the contact time of a drop with a surface was observed.Liang and Mudawar [2] and Šikalo et al.[3] studied heat transfer mechanisms when a drop impinged on a heated surface. An increase in the impact velocity accelerated the spreading velocity during film boiling. In turn, this led to a decrease in the size of secondary droplets. However, the elevated viscosity contributed to an increase in the size of secondary droplets, while a reduction in the surface roughness decreased their size by more than 15%. Moreover, the factor of changing an impingement angle was examined. In particular, the size of child droplets did not depend much on the impingement angle, when it was ϕ > 45 • . However, at ϕ < 15 • , secondary droplets became much smaller.An experimental study by Clavijo et al. [6] considered the effect of the surface inclination angle on the propagation dynamics of a drop over the surface after an impact. After the drop spreads and reaches its maximum diameter, reverse processes occur, i.e., a drop is formed from the film. For example, a surface slope angle of 67.4 • provides ma...

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Mass transfer characterization for hydrocarbon liquid–particle collision based on sensitive tracing of fluorescent probe

Sun

Wang

et al. 2022

AIChE Journal

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The heat and mass transfer characteristics during the collision process of hydrocarbon droplets and polyethylene particles in a liquid‐containing gas–solid polyethylene fluidized bed reactor significantly affect the product quality. In this work, the mass transfer process of single‐component hydrocarbon and bi‐component hydrocarbon liquid films on the polyethylene particle surface were quantitatively characterized by a newly developed experimental approach, based on a novel synthesized hydrocarbon liquid soluble fluorescent probe for sensitive tracing of hydrocarbon liquid diffusion. It was found that the boiling point and surface tension of the liquid as well as the surface temperature of the particle are the key factors affecting the mass transfer properties of the liquid film. Marangoni convection was observed and characterized on the particle surface. The critical time for the onset of Marangoni flow is between 4 and 8 s.

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An experimental study of droplet-particle collisions

Cited by 82 publications

References 13 publications

Collisions of droplets on spherical particles

Collisions of droplets on spherical particles

The Impact of Single- and Multicomponent Liquid Drops on a Heated Wall: Child Droplets

Mass transfer characterization for hydrocarbon liquid–particle collision based on sensitive tracing of fluorescent probe

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