Effect of magnetic field on 3D flow and heat transfer during solidification from a melt

Bouabdallah, Saïd; Bessaïh, Rachid

doi:10.1016/j.ijheatfluidflow.2012.07.002

Cited by 34 publications

(12 citation statements)

References 33 publications

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“…The value of the permeability coefficient C can be expected to depend on the morphology of the mushy zone. No consensus was found on the value of the permeability coefficient in the literature [24,[43][44][45][46][47]. The effects of this parameter on numerical results are therefore reported here.…”

Section: Mathematical Formulationmentioning

confidence: 92%

Sensitivity of Numerical Predictions to the Permeability Coefficient in Simulations of Melting and Solidification Using the Enthalpy-Porosity Method

2019

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The high degree of uncertainty and conflicting literature data on the value of the permeability coefficient (also known as the mushy zone constant), which aims to dampen fluid velocities in the mushy zone and suppress them in solid regions, is a critical drawback when using the fixed-grid enthalpy-porosity technique for modelling non-isothermal phase-change processes. In the present study, the sensitivity of numerical predictions to the value of this coefficient was scrutinised. Using finite-volume based numerical simulations of isothermal and non-isothermal melting and solidification problems, the causes of increased sensitivity were identified. It was found that depending on the mushy-zone thickness and the velocity field, the solid–liquid interface morphology and the rate of phase-change are sensitive to the permeability coefficient. It is demonstrated that numerical predictions of an isothermal phase-change problem are independent of the permeability coefficient for sufficiently fine meshes. It is also shown that sensitivity to the choice of permeability coefficient can be assessed by means of an appropriately defined Péclet number.

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Section: Mathematical Formulationmentioning

confidence: 92%

Sensitivity of Numerical Predictions to the Permeability Coefficient in Simulations of Melting and Solidification Using the Enthalpy-Porosity Method

2019

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“…According to the methodology of the study of an oscillatory flow (unsteady) exposed to an external uniform magnetic field (Gelfgat and Yoeseph, [12]; Bessaï h and Bouabdallah, [13]; Bouabdallah and Bessaih, [14]; Ghernaout et al [15]), we consider in this study a magnetic field applied in two directions: horizontal (Bx) and vertical (By), and the Hartmann number varying from Ha = 0, 5, 10, 20, 30, 50 and 100. Whereas, for the molten metals and semi-conductors with the length scale of the cavity (L = 0.15 m), the applied magnetic field is of the order of 0.2 to 0.5 Tesla.…”

Section: Effect Of Magnetic Field On the Oscillatory Flowmentioning

confidence: 99%

“…Stability diagrams were obtained and showed a strong dependence of the critical Grashof number and the dimensionless critical frequency for various values of the Hartmann number. After, Bouabdallah and Bessaih [14] examined the effect of magnetic field on the flow and the three-dimensional heat transfer during phase change of a liquid metal. They have shown that the magnetic field causes a significant control of the shape of the solid/liquid interface, and for high values of the Hartmann number (Ha = 100), the convection is suppressed and the interface is regular.…”

Section: Introductionmentioning

confidence: 99%

Double Diffusive Natural Convection in Binary Mixture Under the Effect of External Magnetic Field: Steady and Oscillatory State

Ghernaout¹,

Bouabdallah²,

Teggar³

et al. 2015

IJHT

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In this paper, double diffusive natural convection in binary mixture under the effect of external magnetic field for the steady and the oscillatory state is numerically investigated. For this end, a square cavity filled with a binary mixture has been considered; the cavity is exposed to opposing solute and thermal gradients. An external uniform magnetic field is applied separately in two directions (i.e. horizontal and vertical). The following flow parameters were considered: Prandtl number Pr = 0.71, Schmidt number Sc = 3.5 and buoyancy ratio N = 0.75, 1.0, and 1.25. The finite volume method with SIMPLER Algorithm was used to solve numerically the mathematical model. The model was validated and showed good agreement with experimental results of the literature. The obtained results showed a strong dependence of the structure of thermal and solutal effect to the buoyancy ratio. The oscillatory double diffusive flow occurs for a periodic time where the phenomenon change around in each period time. A critical thermal Rayleigh number RaTCr and corresponding dominated frequency for the onset of oscillatory double diffusive convection were determined for each N and for different values of Hartman number (0, 25, 50, and 100).

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“…In the last few years, a growth of interest in using of the magnetic fields in processes and unit operations in the scientific community was observed. Externally applied static magnetic field was used primarily to intensify the process of crystal growth [40,41] or during solidification of metal alloys [42,43]. The rotating magnetic field can be successfully used in the crystallization process [44][45][46][47], fluidization [48,49], metallurgy [50,51], or even to increase the intensity of the dissolution process, as an alternative for mechanical mixing.…”

Section: Literature Surveymentioning

confidence: 99%

A Comparison of Mass Transfer Coefficients between Rotating Magnetic Field Mixer and Stirred Tank Reactor

Story¹,

Kordas²,

Rakoczy³

2015

Mass Transfer - Advancement in Process Modelling

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The mass transfer process is the subject of many experimental studies in chemical engineering and also one of the most commonly used processes. Unfortunately, the mechanism of this process is still not fully understood, especially when nonstandard methods of intensification of mass transfer are used. In this investigation, the use of an alternating magnetic field action AMFs causing mass transfer was taking into consideration. As a result of the flow of electrically conductive fluid near the alternating magnetic field, electromagnetic forces can be generated within the liquid.These forces arise as a result of interaction between the magnetic field and the electric current. They are responsible for the rotation and consequently cause movement of the fluid on which they act. Therefore, there is the possibility of using these properties in the construction of a nonintrusive mixing stirrer.The aim of this study is to determine the mixing time, the power consumption and the mixing efficiency in the mass transfer process that is induced under the action of RMF. The present study compared the mass transfer coefficient of two reactor types RMF mixer and stirred tank reactor.

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Effect of magnetic field on 3D flow and heat transfer during solidification from a melt

Cited by 34 publications

References 33 publications

Sensitivity of Numerical Predictions to the Permeability Coefficient in Simulations of Melting and Solidification Using the Enthalpy-Porosity Method

Sensitivity of Numerical Predictions to the Permeability Coefficient in Simulations of Melting and Solidification Using the Enthalpy-Porosity Method

Double Diffusive Natural Convection in Binary Mixture Under the Effect of External Magnetic Field: Steady and Oscillatory State

A Comparison of Mass Transfer Coefficients between Rotating Magnetic Field Mixer and Stirred Tank Reactor

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