An Improved Model for the Flow in an Electromagnetically Stirred Melt during Solidification

Poole, Gregory M.; El-Kaddah, N.

doi:10.1007/s11663-013-9944-3

Cited by 19 publications

(9 citation statements)

References 28 publications

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“…In the equixed zone, the initial nucleus was surrounded by liquid steel and it moved freely with fluid flow. It should be treated as slurry zone and a apparent viscosity model were used to simulate fluid flow, shown as Equation (6) [18]. As the solid fraction exceeded the coherent fraction (f scr = 0.275), equiaxed grains coherent with each other and the mushy zone should be treated as porosity media.…”

Section: Fluid Flow and Mass Transfermentioning

confidence: 99%

Numerical Simulation of Solidification Behavior and Solute Transport in Slab Continuous Casting with S-EMS

Jiang

Zhu

Zhang

2019

Metals

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A 3D numerical model was built to investigate the transport phenomena in slab continuous casting process with secondary electromagnetic stirring (S-EMS). In the model, the columnar grain grew from strand surface and it should be treated as a porous media. While for the equiaxed zone, the nucleated grain moves with fluid flow in the earlier stage and it was regarded as a slurry. The model was validated by measured strand surface temperature and magnetic induction intensity. The results show that the solidification end near the 1/4 width of slab was postponed, due to the liquid flow from a submerged entry nozzle injected to the strand’s narrow face. As the linear stirring in the same direction is applied, liquid moves from side B to side A and then penetrates deep downward with higher temperature. In the later stage, the solidification end near the side A is postponed and the solute element is concentrated. When linear stirring in the opposite direction is used, the solidification end near the side A moves backward, while that near the side B moves forward. Moreover, it is found that the solute segregation in the side B is deteriorated, but that in the side A is reduced. As rotational stirring mode is applied, the evenness of solidification end profile is improved and the centerline segregation is reduced, especially with higher current intensity. Therefore, it is concluded that the linear stirring mode is not appropriated for slab casting, while the rotational stirring mode is more suitable.

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Section: Fluid Flow and Mass Transfermentioning

confidence: 99%

Numerical Simulation of Solidification Behavior and Solute Transport in Slab Continuous Casting with S-EMS

Jiang

Zhu

Zhang

2019

Metals

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“…For the equiaxed dendrite zone, the initial formation of nucleus is surrounded by liquid metal and moves freely with liquid flow induced by solidification shrinkage, gravity and EMS forces. In this period, the mushy zone should be treated as slurry and the varying apparent viscosity model, shown as Equation , is used to simulate the fluid flow through the mushy region. With the decrease of temperature, the equiaxed dendrite grows continuously and secondary dendrite arms gradually contact with one another, which is deemed to be the coherent point, where the solid fraction is defined as f scr and it is determined by the dendrite morphology as Equation , according to Poolea and El‐Kaddah .…”

Section: Mathematical Modelmentioning

confidence: 99%

“…The columnar dendrite region is treated as a porous zone and a generalized approach, which depended on the primary and secondary arm spacing is used to calculate permeability . As the initial growing crystal can move freely with the liquid in equiaxed dendrite zone, a variable apparent viscosity model is used to simulate the fluid flow. In the later stage of equaxied dendrite solidification, the equiaxed zone is also treated as porous media.…”

Section: Introductionmentioning

confidence: 99%

Flow and Solidification in Billet Continuous Casting Machine with Dual Electromagnetic Stirrings of Mold and the Final Solidification

Jiang

Zhu

2014

steel research int.

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A 3D numerical model coupling the electromagnetic field, fluid flow, heat transfer and solidification phenomena was developed to simulate the 160 mm Â 160 mm billet continuous casting process of SWRT82B steel with dual electromagnetic stirrings of mold and the final solidification. The columnar region was treated as a porous zone and a generalized approach was used to calculate permeability, while for the equiaxed zone, a variable apparent viscosity model was applied to simulate the fluid flow at the initial growing stage of equiaxed dendrite. The model was validated by the measured data of magnetic induction intensity in the stirrer center and strand surface temperature. The results show that it is indispensable to consider the solidification phenomenon in the mold zone with EMS, as the fluid flow mechanism near the meniscus is quite different. With the current intensity of M-EMS and F-EMS increasing, the tangential velocity of molten steel rises and the central temperature decreases. As the F-EMS is applied, the nature convection mechanism is destroyed and the temperature is promoted to distribute evenly in the mushy zone. Moreover, the results show that the coherent solid fraction has a significant effect on the temperature distribution and the fluid flow in F-EMS zone.

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“…This formulation will be given in broad outline only, since the derivation of the model equations are given in reference. 26) Even further elaboration on the necessary steps in modeling such systems may be found in other references. 8,10,18) …”

Section: Model Formulationmentioning

confidence: 99%

Effect of Coil Design on the Temperature and Velocity Fields during Solidification in Electromagnetic Stirring Processes

Poole

El-Kaddah

2014

ISIJ Int.

Self Cite

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This paper examines the role of induction coil design on stirring of molten metal in electromagnetic (EM) solidification processes. A model is presented to describe the EM, heat transfer, and fluid flow phenomena in these processes. It is based on a dual-zone description of the mushy region, and accounts for damping of turbulence by the solidified crystallites. The electromagnetic field equations were solved using the mutual inductance technique, while the temperature and turbulent flow fields were calculated using the control volume method. Calculations were performed for solidification of an Al-Cu alloy placed in a stationary magnetic field generated by an induction coil. The effect of coil design on the flow structure was investigated for three different coil positions. It was found that changing the coil position significantly alters the flow pattern from four recirculating loops when the coil is above the midsection of the melt to two loops, typical of a travelling magnetic field, when the coil is at the base of the melt. This significantly modifies the rate of solidification across the ingot, as well as the temperature gradient, in the mushy region. The decay of the velocity and turbulent fields in the mushy region was found to be exponential, with the maximum rate of decay at the solidification front. These results indicate that through changes in coil design, it is possible to control the flow characteristics and solidification behavior in the molten metal.

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An Improved Model for the Flow in an Electromagnetically Stirred Melt during Solidification

Cited by 19 publications

References 28 publications

Numerical Simulation of Solidification Behavior and Solute Transport in Slab Continuous Casting with S-EMS

Numerical Simulation of Solidification Behavior and Solute Transport in Slab Continuous Casting with S-EMS

Flow and Solidification in Billet Continuous Casting Machine with Dual Electromagnetic Stirrings of Mold and the Final Solidification

Effect of Coil Design on the Temperature and Velocity Fields during Solidification in Electromagnetic Stirring Processes

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