Model Experiment on Inclusion Removal by Bubble Flotation Accompanied by Particle Coagulation in Turbulent Flow

We design and experimentally demonstrate a migration of electrically neutral particles in liquids driven by electric current according to the discrepancies of their electrical conductivities. A force from electric current to electrically neutral particles has been identified to drive the particles toward the lateral surface from the centre of suspension via three distinguishable zones, namely pushing, trapping and expelling zones. The driving force can overtake gravity in practical cases. The property of the force is found neither similar to that of the force in electromagnetophoresis nor similar to that of the electromigration force in terms of direction and magnitude. An expression for the force at the pushing zone has been developed based on the numerical calculation of the thermodynamics of suspension fluids.The excellent agreement between numerical calculations and experimental data demonstrates that our calculation provides fundamental and predictive insight into particles separation from the liquids. Therefore, it is possible to use the force in many engineering applications such as separation of particles according to the differences of their electrical conductivities. *Corresponding authors.

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“…[17][18][19][20] As mentioned in Fig.1 . The suspension is subject to an electrical potential difference.…”

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confidence: 98%

Electric current-driven migration of electrically neutral particles in liquids

Zhang

Qin

2014

Applied Physics Letters

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“…It is well known that gas blowing has been widely applied in metallurgical processes to enhance the inclusion removal and metallurgical reaction rates and to homogenize the temperature and composition of the melt, and the number, arrangement and gas flow rate of bottom blowing have a great impact on these transport phenomena. Hence, the study of inclusions removal behavior and mixing phenomena under different arrangement of gas blowing in gas-stirred system is necessary and has received considerable attention [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] over the years. Inclusion behavior in gas-stirred system involves complex phenomena, such as inclusion transport due to liquid flow, inclusion growth due to inclusion-inclusion collision and inclusion removal due to flotation and attachment to bubbles, and some models have been proposed to describe these behaviors.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulations of Inclusion Behavior and Mixing Phenomena in Gas-stirred Ladles with Different Arrangement of Tuyeres

Lou

Zhu

2014

ISIJ Int.

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A CFD-PBM (Computational Fluid Dynamic-Population Balance Model) coupled model has been developed to investigate the effects of different number and position of bottom tuyeres and gas flow rate on the bubbly plume flow, inclusion removal and mixing phenomena in gas-stirred ladle. It is found that the dual blowing gives a shorter mixing time and higher inclusion removal ratio in comparison with the center blowing or eccentric blowing with one tuyere. With the increasing of separation angle of two tuyeres, the inclusion removal ratio increases, while mixing time decreases first and then increases. With the increasing of radial position of two tuyeres, the inclusion removal first increases and then decreases, and the mixing time decreases until the radial position exceeds 0.7R from the bottom center, where R is the bottom radius of ladle. It is recommended to use the two tuyeres placed at radial position of 0.6R and the angle of 135 deg in ladle to improve the joint efficiency both the inclusion removal and mixing. With the gas flow rate increasing, the efficiency both mixing and inclusion removal with the optimized tuyeres arrangement increases, however when the gas flow rate exceeds 300 NL/min in 150 ton ladle, the removal ratio and mixing time change little.

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“…[1][2][3][4][5][6][7][8] Some research has been carried out to remove inclusions in molten steel during a ladle treatment as well as during a tundish operation. [9][10][11][12] However, it is impossible to obtain a completely clean steel with the current steel production technology. Clogging is closely related to the inclusion behavior in steel.…”

Section: Introductionmentioning

confidence: 99%

Turbulent Flow Phenomena and Ce2O3 Behavior during a Steel Teeming Process

Jonsson

Ersson

et al. 2013

ISIJ Int.

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Steel flow phenomena and Ce2O3 inclusion behavior are presented in this paper. A three-dimensional model was developed to describe the steel flow phenomena and the inclusion behavior during a teeming process. The Kim-Chen modified k-ε turbulent model was used to simulate the turbulence properties and the Height-of-Liquid model was used to capture the interface between gas and steel. A Lagrangian method was then used to track the inclusions and to compare the behaviors of different-size inclusions in the steel flow. In addition, a statistical analysis was carried out by the use of a stochastic turbulence model to investigate the behaviors of different-size inclusions at different nozzle regions. The results show that the steel flow was the most turbulent at the connection region of the straight pipe part and the expanding part of the nozzle. All inclusions with a diameter smaller than 20 μ m were found to have a similar trajectory and velocity distribution in the nozzle. However, inertia force and buoyancy force were found to play an important role for the behaviors of large-size inclusions/clusters. The statistical analysis results indicate that the regions close to the connection region between different angled nozzle parts seem to be very sensitive with respect to deposition of inclusions.

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Model Experiment on Inclusion Removal by Bubble Flotation Accompanied by Particle Coagulation in Turbulent Flow

Cited by 58 publications

References 30 publications

Electric current-driven migration of electrically neutral particles in liquids

Electric current-driven migration of electrically neutral particles in liquids

Numerical Simulations of Inclusion Behavior and Mixing Phenomena in Gas-stirred Ladles with Different Arrangement of Tuyeres

Turbulent Flow Phenomena and Ce2O3 Behavior during a Steel Teeming Process

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