Interactions in droplet and particle system of near unity size ratio

Mitra, Subhasish; Evans, Geoffrey M.; Doroodchi, Elham; Pareek, Vishnu; Joshi, Jyeshtharaj B.

doi:10.1016/j.ces.2017.03.059

Cited by 48 publications

(30 citation statements)

References 38 publications

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“…The experimental setup consists of a droplet–particle collision system and an image capture system shown in Figure with reference of Mitra's . In the collision system, 6.2 mm polyethylene particle is used as the spherical target.…”

Section: Experimental Setup and Methodsmentioning

confidence: 99%

“…The experimental setup consists of a droplet-particle collision system and an image capture system shown in Figure 1 with reference of Mitra's. 26 In the collision system, 6.2 mm polyethylene particle is used as the spherical target. The T-type thermocouple passes through the particle center from bottom by a semichannel locating the temperature measurement point at 2/3, which response time is 0.5 s. In addition to the thermocouple, a thermal imager is used to proof the results of the thermocouple.…”

Section: Experimental Setup and Methodsmentioning

confidence: 99%

“…This group observed rebound and complete disintegration under 250–350°C, which were divided by a critical Weber number range rather than a single threshold. They also studied the droplet–particle with the size ratio close to 1 under normal and elaborated on the nucleate boiling, and gave a time‐dependent scheme for different stages. They then studied heat transfer in the film boiling state and measured dynamic contact angles, whose continuous time varying profile was used as a wall boundary condition for the cold interactions.…”

Section: Introductionmentioning

confidence: 99%

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Experimental characterization of liquid film behavior during droplets–polyethylene particle collision

et al. 2020

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Nowadays, the droplet–particle collision characteristics in the gas‐phase ethylene polymerization process are still unclear. The high‐speed photography and a quasi‐circle imaging approach are employed to study the collision interaction characteristics between liquid droplets and polyethylene particles. The liquid film evolution is studied through variations of the film thickness on the particle north pole, the dynamic contact angle, center angle and film thickness at the maximum extension. Results have found that for n‐hexane the threshold temperature of the recoil happening increases with increasing initial Weber number, but for 1‐hexene it is stable. Over 70°C evaporation and splash occurs immediately. Under low Weber numbers, the water droplet stays for damping oscillations, the reference stable height of which is linearly related to temperatures. Moreover, three regimes of film thickness variation with time are identified and mathematically described, while Regime 3 characteristics are found strongly dependent on the liquid species, Weber number, and particle temperature.

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Section: Experimental Setup and Methodsmentioning

confidence: 99%

Section: Experimental Setup and Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental characterization of liquid film behavior during droplets–polyethylene particle collision

et al. 2020

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“…Dynamic wetting of particle surface is an important research aspect in the area of multiphase flows. Ample process applications such as spray coating of tablets in pharmaceutical applications (Hardalupas et al, 1999 ), vaporization of vacuum gas oil feed droplets in contact with catalyst particles in fluid catalytic cracking unit (Ge and Fan, 2007 ; Mitra et al, 2013 , 2015 , 2016 , 2017 ; Nguyen et al, 2015 ; Banitabaei and Amirfazli, 2017 ), spray drying (Charalampous and Hardalupas, 2017 ), thermal cracking of bitumen feed in fluid coking unit, scrubbing of particulate matters from off-gas stream (Mitra et al, 2013 , 2015 , 2016 , 2017 ) require adequate surface wetting of particles. Dynamic wetting of particle surface resulting from such interactions contribute significantly to the liquid distribution on particle surface, associated heat-mass transport processes, and chemical reactions each of which governs the process performance.…”

Section: Introductionmentioning

confidence: 99%

“…Central to the surface wetting behavior is the three-phase contact line motion which changes drastically as a consequence of the several outcomes that are possible based on interacting droplet-particle size ratio (Δ) such as deposition, rebound, disintegration (Δ < 1) (Ge and Fan, 2007 ; Mitra et al, 2013 , 2016 ); capture, penetration, disintegration (Δ> 1) (Mitra et al, 2015 ), deposition, film formation and disintegration (Δ ~ 1) (Bakshi et al, 2007 ; Gac and Gradon, 2014 ; Banitabaei and Amirfazli, 2017 ; Mitra et al, 2017 ). For Δ < 1 scenario, upon impact on the solid surface, droplet spreads into a liquid lamella wherein the impact kinetic energy is transformed into the surface energy and the spreading process continues until the kinetic energy is completely dissipated and a maximum spreading state is reached.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Surface Wetting and Heat Transfer in a Droplet-Particle System of Less Than Unity Size Ratio

Mitra

Evans

2018

Front. Chem.

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Dynamic surface wetting of particles in contact with droplet is a complex phenomenon ubiquitously encountered in many multiphase systems of industrial importance. In this study, we address this aspect by investigating impact behavior of a water droplet (diameter = 2.9 ± 0.1 mm) in the Weber number (We) range from ~4 to 104 on a stationary spherical brass particle (diameter = 10 mm) with and without heat transfer using a combination of high speed imaging and computational fluid dynamics (CFD) modeling approach. In cold state interactions (20°C), droplet exhibited oscillatory interfacial motion comprising periodic spreading and recoiling motion. Interactions involving heat transfer were studied in film boiling regime (350°C) and two outcomes were noted—droplet rebound and disintegration. A coupled Level Set and Volume of Fluid (VOF) approach based multiphase CFD model was utilized to predict the dynamic spread ratio and transient evolution of droplet shape during the interaction. To capture the complex contact line motion realistically, a continuous time varying profile of experimentally measured dynamic contact angles was used as a wall boundary condition for the cold interactions which provided good agreement with experimentally measured droplet spread ratio. In film boiling regime, droplet spread ratio was correlated to impact Weber number and a power law trend was obtained. Rebound and disintegration outcomes were characterized by the droplet-particle contact time. For simulating interactions in film boiling regime, a constant contact angle in the limit of super-hydrophobic surface was implemented in the CFD model to account for the apparent non-wetting effect due to vapor film formation at the contact area. A sensitivity analysis was performed involving three different contact angle boundary conditions (θs = 150, 160, and 170°) to represent the surface hydrophobicity. CFD model predicted interaction outcomes and droplet spread ratios were in reasonable agreement with the experiment at different impact Weber numbers. Increase in spherical surface heat flux and corresponding rise in droplet temperature at different impact Weber numbers were also quantified which showed an increasing trend up to a critical Weber number for droplet disintegration.

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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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Interactions in droplet and particle system of near unity size ratio

Cited by 48 publications

References 38 publications

Experimental characterization of liquid film behavior during droplets–polyethylene particle collision

Experimental characterization of liquid film behavior during droplets–polyethylene particle collision

Dynamic Surface Wetting and Heat Transfer in a Droplet-Particle System of Less Than Unity Size Ratio

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

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