Reynolds Number Effects on Particle Agglomeration in Turbulent Channel Flow

Afkhami, Mohammad; Hassanpour, Ali; Fairweather, Michael; Njobuenwu, Derrick O.

doi:10.1016/b978-0-444-63456-6.50162-9

Cited by 4 publications

(2 citation statements)

References 7 publications

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“…In 2015, they further investigated particle deposition and resuspension behavior in gas-cooled reactors (Barth et al 2015). In addition, Afkhami et al (2014Afkhami et al ( , 2015 employed LES and the discrete element method to study particle dispersion and agglomeration behavior in a horizontal channel flow and concluded that both particle-particle interactions and Reynolds number have a significant effect on these particle behaviors across the flow Reb range considered (2100-8260). Li et al (2016) also used direct numerical simulation to study particleflow turbulence interaction in the wall region of a flat plate boundary layer.…”

Section: Introductionmentioning

confidence: 99%

Reynolds number dependence of particle resuspension in turbulent duct flows

Zhao

Wang

et al. 2018

Chemical Engineering Science

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Particle resuspension in a fully developed turbulent square duct flow is simulated using oneway coupled large eddy simulation coupled with a Lagrangian particle tracking technique for a range of bulk Reynolds numbers (36.5k, 83k and 250k) and four particle sizes ranging from 5 to 500 m (St=0.01~2415) considered. Results obtained for the single-phase flow show good agreement with experimental data. Predictions of the time-dependent particle-laden flows demonstrate that the secondary flow mainly dominates particle resuspension in the regions near the center and sidewalls of the duct. It is found that particle resuspension decreases with particle size. The smaller particles tend to be more prone to resuspension, and are resuspended for a longer duration than larger particles. The mean particle resuspension velocity is found to increase with the duct height. In addition, particle resuspension in the vertical direction increases with Reynolds number while the effect of particle size on particle resuspension decreases. The resuspension rate in the spanwise direction fluctuates more as the Reynolds number increases. It is also found that the average particle resuspension rate in the lower half of the duct is always close to 0.5, and is independent of time, particle size and Reynolds number. Based on a dynamic analysis, the drag force is found to dominate the resuspension of small particles, while the lift force tends to dominate particle resuspension with increasing particle size. For low Reynolds number (36.5k and 83k) flows, the drag force plays an important role in the upper regions of the lower half of the duct, but the lift force dominates particle behaviour in the lower regions. It can be concluded that the effects of duct height on particle behaviour decline significantly with Reynolds number.

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Section: Introductionmentioning

confidence: 99%

Reynolds number dependence of particle resuspension in turbulent duct flows

Zhao

Wang

et al. 2018

Chemical Engineering Science

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“…Turbulence and agitation may also result in re-agglomeration of particles [25]. Further, it is to be noted that the flow velocities can effect segregation, depending on the local flow patterns.…”

Section: Supplementary Video#1mentioning

confidence: 99%

Synchrotron radiographic studies of ultrasonic melt processing of metal matrix nano composites

Mirihanage

Tamayo-Ariztondo

et al. 2016

Materials Letters

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Fast synchrotron radiography was used to investigate ultrasonic cavitation bubble formation and their dynamics during liquid metal processing of Al-Cu metal matrix nano composites (MMNC) in comparison with conventional alloys. The experimental observations showed enhanced cavitation potential in MMNC melts, due to the presence of Al 2 O 3 nano particles which believed to be acting as heterogeneous nuclei for bubble formation. Quantitative image analysis demonstrates that the addition of nano particles increases melt agitation partially, while introducing higher flow velocity variations across the melt. This suggests that the presence of nano particles may substantially alter propensity for ultrasonic treatment effects during solidification processing of MMNCs. Highlights• Fast X-ray imaging of ultrasound cavitation in Al-Cu metal matrix nano composite melts.• Nano particles significantly enhance the ultrasonic cavitation bubble formation potential.• Higher flow velocity variation across the melt with increased cavitation activity was found from the experimental observations.

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Physical methods of processing melts of metal matrix composites: Сurrent state and prospects

Деев

Прусов

2022

Izv.VUZ. Tsvet. Met.

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This review focuses on the known theoretical and experimental results in the field of obtaining metal matrix composite materials by processing the melts using physical methods in the conditions of casting and metallurgical processes. The possibilities, advantages and disadvantages of various physical impact methods are considered from the standpoint of their effect on the structural and morphological characteristics, physicomechanical and operational properties of cast composite materials based on aluminum and its alloys. The paper provides a classification and a detailed description of physical methods used for melt processing when obtaining metal matrix composites depending on the melt state during processing (melting, pouring and crystallization) and according to the physical principle of the effects applied (thermal, electromagnetic, cavitation, mechanical, etc). The paper describes a contemporary view of the laws and mechanisms of the effect exerted by melt processing using physical methods on the structure and phase formation processes of as-cast metal matrix composites. The currently known effects of the impact on their structure are described from a qualitative and quantitative point of view, in particular, effects associated with a change in the wettability of particles, their distribution, dispersion and morphology, as well as with a change in the structural state of the matrix material. The paper systematizes the data on the properties of metal matrix composites obtained using physical impacts on the melt during melting and crystallization. The research shows the prospects for the development and practical application of physical impact methods for melts in the production of metal matrix composites based on various matrix materials and reinforcement systems including endogenously, exogenously and integrally reinforced composite materials. Priority areas of theoretical research and experimental development are discussed highlighting discussion areas and issues in the field of obtaining metal matrix composites using physical impacts on melts during melting and crystallization. Areas for future research in this field are proposed based on the systematic analysis of key problems limiting the widespread industrial use of physical methods for melt processing.

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Reynolds Number Effects on Particle Agglomeration in Turbulent Channel Flow

Cited by 4 publications

References 7 publications

Reynolds number dependence of particle resuspension in turbulent duct flows

Reynolds number dependence of particle resuspension in turbulent duct flows

Synchrotron radiographic studies of ultrasonic melt processing of metal matrix nano composites

Physical methods of processing melts of metal matrix composites: Сurrent state and prospects

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