Drag coefficient fluctuation prediction of a single bubble rising in water

Yan, Xiang-Ping; Yan, Jia; Wang, Lijun; Cao, Yijun

doi:10.1016/j.cej.2017.01.137

Cited by 63 publications

(35 citation statements)

References 34 publications

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“…The bubble shape, which plays a key role in bubble dynamics, is determined by the physical properties of the fluid, the bubble size, and its velocity. The aspect ratio and the drag coefficient (a dimensionless quantity that is used to quantify the drag force) are two fundamental parameters for predicting the velocity of a rising bubble and thus for modeling bubbly flows. , Different models have been proposed for the prediction of these parameters, e.g., correlations combining Weber number with Eötvös number and Weber number with Reynolds number have been shown to satisfactorily predict aspect ratios, whereas a correlation that combines Reynolds number, Eötvös number, and Weber number has been proposed to calculate the fluctuation of drag coefficient …”

Section: Introductionmentioning

confidence: 99%

Effect of Particle Size on the Rising Behavior of Particle-Laden Bubbles

2019

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The rising behavior of bubbles, initially half and fully coated with glass beads of various sizes, was investigated. The bubble velocity, aspect ratio and oscillation periods were determined using high-speed photography and image analysis. In addition, the acting forces, drag modification factor and modified drag coefficient were calculated and interpreted. Results show that the aspect ratio oscillation of the rising bubbles is similar, irrespective of the attached particle size. As the particle size is increased, the rising bubbles have a lower velocity and aspect ratio amplitude, with the time from release to each aspect ratio peak increasing. Higher particle coverage is shown to decrease the bubble velocity and dampen the oscillations, reducing the number of aspect ratio peaks observed. The highest rise velocities correspond to the lowest aspect ratios and vice versa, whereas a constant aspect ratio yields a constant rise velocity, independent of the particle size. Force analysis shows that the particle drag modification factor increases with the increased particle size and is greatest for fully laden bubbles. The modified drag coefficient of particle-laden bubbles increases with the increased particle size, although it decreases with Reynolds number independent of the particle size. The drag force exerted by the particles plays a more dominant role in decreasing bubble velocities as the particle size increases. The results and interpretation produced a quantitative description of the behavior of rising particle-laden bubbles and the development of correlations will enhance the modeling of industrial applications.

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Section: Introductionmentioning

confidence: 99%

Effect of Particle Size on the Rising Behavior of Particle-Laden Bubbles

2019

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“…Compared with solid particles, bubbles are considered as deformable particles with a movable interface, and their dispersion in flotation turbulent systems is more complicated 103 . The dispersion process of bubble is a comprehensive function of turbulence, bubble characteristics, and gas–liquid interface properties.…”

Section: Computational Fluid Dynamics Numerical Simulation Of Flotation Processmentioning

confidence: 99%

Recent advances in computational fluid dynamics simulation of flotation: a review

Wang

Yan

et al. 2021

Asia-Pacific J Chem Eng

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Flotation process is a multi‐phase and multi‐scale complex flow system, in which hydrodynamics plays an indispensable role. In recent years, computational fluid dynamics (CFD) numerical simulation has gradually become a powerful tool for studying flotation. In this review, the theories of CFD numerical simulation in flotation research were reviewed, involving various turbulence models and multi‐phase flow simulation approaches. An attempt has been made to analyze and discuss the characteristics and applicability of different turbulence models and multi‐phase flow simulation approaches in flotation researches in detail. The CFD simulation of two commonly used flotation devices, that is, mechanically agitated flotation machine and flotation column, has been reviewed in detail. The detailed principles, operation, and hydrodynamic of flotation devices were discussed from the viewpoint of CFD. The advances made in CFD simulation for studying flotation process, including particle suspension, bubble dispersion, particle–bubble collision, attachment, and detachment subprocesses have been critically analyzed. Focused analysis was given on the influence mechanism of turbulence on the particle–bubble interactions. Finally, the gaps in the available literature are discussed and potential research directions are also proposed.

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“…A drag coefficient for bubbles can still be defined. However, experiments on the rising of a single bubble in water demonstrated that the drag coefficient C d shows fluctuation and C d is not only related to the Reynolds number but also to the geometry of the bubble (Tomiyama et al 1998;Yan et al 2017). The variations of the drag coefficient could thus affect the scaling of the contraction velocity (see § 4.1).…”

Section: Asymptotic Contraction Velocitymentioning

confidence: 99%