Mathematical modeling and computer simulation of molten metal cleansing by the rotating impeller degasser

Warke, Virendra S.; Tryggvason, Grétar; Makhlouf, M. M.

doi:10.1016/j.jmatprotec.2004.10.017

Cited by 44 publications

(36 citation statements)

References 5 publications

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“…Several approaches have been developed for degassing in the last several decades; for example, re-melting degassing [7], vacuum degassing [8,9], ultrasonic degassing [10,11], and spray degassing [12,13], as well as rotary impeller degassing with nitrogen, argon, or a mixture of the inert gases and chlorine as a purge gas [14][15][16]. Nevertheless, the research on technology and equipment of high-efficiency degassing depends on reliable physical property data and parameters of degassing mechanisms, which are still incompletely understood.…”

Section: Introductionmentioning

confidence: 99%

Study of Adsorption of Hydrogen on Al, Cu, Mg, Ti Surfaces in Al Alloy Melt via First Principles Calculation

Liu

Huang

Xiao

et al. 2017

Metals

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Adsorption of hydrogen on Al(111), Cu(111), Mg(0001), and Ti(0001) surfaces have been investigated by means of first principles calculation. The calculation of surface energy indicates that Mg(0001) is the most stable surface, while Ti(0001) is the most unstable surface among all the four calculated surfaces. The obtained adsorption energy shows that the interaction between Al and H atoms should be energetically unfavorable, and the adsorption of hydrogen on Mg(0001) surface was found to be energetically preferred. Besides, the stability of hydrogen adsorption on studied surfaces increased in the order of Al (111), Ti(0001), Cu(111), Mg(0001). Calculation results also reveal that hydrogen adsorption on fcc and hcp sites are energetically stable compared with top and bridge sites for Ti(0001), Cu(111), and Mg(0001), while hydrogen adsorbing at the top site of Al (111)

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Section: Introductionmentioning

confidence: 99%

Study of Adsorption of Hydrogen on Al, Cu, Mg, Ti Surfaces in Al Alloy Melt via First Principles Calculation

Liu

Huang

Xiao

et al. 2017

Metals

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“…Furthermore, the study included the movement of the melt surface, showing the formation of the vortex, even though it used a two-dimensional geometry model. The last relevant contribution to the modeling of rotary degassing was the model of Warke et al [10,11] who simulated the turbulent multiphase flow field that develops in the melt during rotary degassing calculating the mean turbulence dissipation energy and the distribution of gas bubbles in the melt and used both quantities as input into other mathematical models to simulate the removal of dissolved hydrogen and impure solid particles from the melt.…”

Section: Introductionmentioning

confidence: 99%

“…These have been done using commercial codes such as FIDAP [12], Fluent [10,13], Phoenics [1], and others [14]. Although these models are complex and help to understand the agitation phenomena inside the reactor, they do not provide a proper connection between the fluid flow and mass transport phenomena to predict the removal of solid inclusions and dissolved hydrogen.…”

Section: Introductionmentioning

confidence: 99%

“…Although these models are complex and help to understand the agitation phenomena inside the reactor, they do not provide a proper connection between the fluid flow and mass transport phenomena to predict the removal of solid inclusions and dissolved hydrogen. Warke [10,11] modeled degassing by the rotor injector technique dividing the system into three separate but interconnected subsystems which included the turbulent flow fields caused by the impeller rotation, the gas flow injected, and the removal dynamics of particles and dissolved hydrogen. The approach was done using a standard turbulence model and the Eulerian approach for the multiphase fluid, and the connection of the subsystems was performed with parameters like turbulent energy dissipation and bubble distribution.…”

Section: Introductionmentioning

confidence: 99%

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Effect of the Impeller Design on Degasification Kinetics Using the Impeller Injector Technique Assisted by Mathematical Modeling

Abreú-López

Amaro-Villeda

Acosta-González

et al. 2017

Metals

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A mathematical model was developed to describe the hydrodynamics of a batch reactor for aluminum degassing utilizing the rotor-injector technique. The mathematical model uses the Eulerian algorithm to represent the two-phase system including the simulation of vortex formation at the free surface, and the use of the RNG k-ε model to account for the turbulence in the system. The model was employed to test the performances of three different impeller designs, two of which are available commercially, while the third one is a new design proposed in previous work. The model simulates the hydrodynamics and consequently helps to explain and connect the performances in terms of degassing kinetics and gas consumption found in physical modeling previously reported. Therefore, the model simulates a water physical model. The model reveals that the new impeller design distributes the bubbles more uniformly throughout the ladle, and exhibits a better-agitated bath, since the transfer of momentum to the fluids is better. Gas is evenly distributed with this design because both phases, gas and liquid, are dragged to the bottom of the ladle as a result of the higher pumping effect in comparison to the commercial designs.

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“…Agglomeration is not considered in this study. More recently, a Worcester Polytechnic Institute (Worcester, MA) crew [5,[16][17][18] investigated aluminum purification treatment; both agglomeration and flotation were considered through a population balance approach. Their approach is based on the assumption of a perfectly stirred reactor.…”

Section: Introductionmentioning

confidence: 99%

Mathematical Modeling and Computer Simulation of Molten Aluminum Purification by Flotation in Stirred Reactor

Mirgaux

Ablitzer

Waz³

et al. 2009

Metall Mater Trans B

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The removal of inclusions by flotation in mechanically agitated vessels is widely used in liquid aluminum treatments. Originating from different sources (oxide skins, refractory, or recycling wastes), inclusions may have disastrous repercussions such as deterioration of the physical properties of the cast products or difficulties during forging processes. With the aim of both a better understanding of the physical processes acting during flotation and the optimization of the refining process, a mathematical modeling of the behavior of the population of inclusions has been set up. Transport phenomena, agglomeration of inclusions, and flotation are considered here. The model combines population balance with convective transport of the inclusions, in order to calculate the time evolution of the inclusion size distribution. An operator-splitting technique is employed to solve the coupled population balance equation (PBE) and the transport equation. The transport equation is solved using a finite volume technique associated with a total variation diminishing scheme, whereas the PBE resolution relies on the fixed pivot technique developed by Kumar and Ramkrishna. A laboratory-scale flotation vessel is modeled and the results of a two-dimensional (2-D) simulation are presented.

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Mathematical modeling and computer simulation of molten metal cleansing by the rotating impeller degasser

Cited by 44 publications

References 5 publications

Study of Adsorption of Hydrogen on Al, Cu, Mg, Ti Surfaces in Al Alloy Melt via First Principles Calculation

Study of Adsorption of Hydrogen on Al, Cu, Mg, Ti Surfaces in Al Alloy Melt via First Principles Calculation

Effect of the Impeller Design on Degasification Kinetics Using the Impeller Injector Technique Assisted by Mathematical Modeling

Mathematical Modeling and Computer Simulation of Molten Aluminum Purification by Flotation in Stirred Reactor

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