Numerical study of melting in an enclosure with discrete protruding heat sources

Faraji, Mohammad; Qarnia, Hamid El

doi:10.1016/j.apm.2009.08.012

Cited by 51 publications

(14 citation statements)

References 16 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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“…Faraji and El Qarnia [17] studied numerically the melting of n-eicosane (C 20 H 42 ) in a rectangular enclosure heated with three protruding heat sources with a constant and uniform volumetric heat generation on one side while the other sides were thermally insulated (Fig. 4).…”

Section: Melting Due To the Constant Heat Flux (Chf) Boundarymentioning

confidence: 99%

Melting and convection of phase change materials in different shape containers: A review

Dhaidan

Khodadadi

2015

Renewable and Sustainable Energy Reviews

317

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A review of analytical, numerical and experimental investigations of melting and ensuing convection of phase change materials within enclosures with different shapes commonly used for thermal energy storage is presented. The common shapes of the containers being rectangular cavities, spherical capsules, tubes or cylinders (vertical and horizontal depending on orientation of gravity) and annular cavities are covered. Studies focusing on melting within rectangular cavities are categorized into two groups. The first one is melting due to isothermal heating on one or more boundaries, whereas the second is the constant heat flux-assisted melting. Moreover, constrained and unconstrained melting in both spherical and horizontal cylindrical containers were discussed. The effects of the concentric geometry and location of the heating source on melting in horizontal annular spaces are presented. The review concentrated on elucidating the heat transfer mechanisms (conduction and convection) during the multiple stages of the melting process and the effects of these mechanisms on the liquid-solid interface shape and its progress, melting rate, charging time of the storage system, etc. The strength of buoyancy driven-convection varies greatly with the dimensionless Rayleigh or Stefan numbers and depends somewhat on the location of heat source and imposed boundary condition. High dimensionless numbers and/or side position of the heat source ensure the dominant role of natural convection melting, otherwise conduction will be responsible for major melting within the container. Furthermore, the geometrical parameters such as the aspect ratio in rectangular containers and vertical cylindrical ones, diameter or radius in spherical capsules and horizontal cylindrical vessels, and eccentricity in annular cavities are reviewed. In addition, the parameters affecting the thermal behavior of the melting process in various enclosures, i.e. the Nusselt, Rayleigh, Stefan, Prandtl and Fourier numbers and are reviewed.

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“…The viscosity of the slag has been estimated via use of the Mills and Sridhar model, while infinite viscosity has been assumed in the solid regions[37][38][39][40][41][42][43][44] .…”

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confidence: 99%

A CFD analysis of slag properties, electrode shape and immersion depth effects on electric submerged arc furnace heating in ferronickel processing

Karalis

Karkalos

Cheimarios

et al. 2016

Applied Mathematical Modelling

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a b s t r a c tA 2D, steady-state computational fluid dynamics (CFD) analysis of an industrial electric arc furnace (EAF) is presented. The analysis accounts for the electrode shape and immersion depth, as well as for the dependence of Joule heating on the properties of the slag. The equations for the electric potential, momentum and heat transfer were solved across four distinct regions (i.e. air, slag, ferronickel and firebricks) and the final profile of the slag/metal interface was calculated as a function of the operating parameters of the furnace. The results indicate that the amount of Joule heat produced by the Söderberg electrodes increased with increasing applied voltage and electrical conductivity of the slag; the Joule heat peaked for a value of slag electrical conductivity equal to 3 S/m. A highly conductive slag along with a greater electrode immersion depth was found to facilitate the melting process. The maximum slag velocity values computed were of the order of 0.8 m/s in the vicinity of the electrode tips.

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Numerical study of melting in an enclosure with discrete protruding heat sources

Cited by 51 publications

References 16 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

Melting and convection of phase change materials in different shape containers: A review

A CFD analysis of slag properties, electrode shape and immersion depth effects on electric submerged arc furnace heating in ferronickel processing

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