Thermal evolution in the direct chill casting of an Al-4 pct Cu alloy using the low-Reynolds number turbulence model

Nzebuka, Gaius Chukwuka; Waheed, M.A.

doi:10.1016/j.ijthermalsci.2019.106152

Cited by 15 publications

(6 citation statements)

References 22 publications

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“…The transition and film boiling, are nearly ignored because the surface temperature of the billet is below the Leidenforst Point, which is above 573 K for aluminum alloy. Therefore, the heat transfer coefficient in the secondary cooling zone can be presented as follows [ 17 ]:

where h is the convection heat transfer coefficient, T is the temperature, Tα is the free stream temperature. In addition, at the downstreaming zone I and II, set as 200 mm and 300 mm in length, respectively, the heat transfer coefficient expresses as below by Suyitno [ 29 ]:

where,

, T sat = 363 K, T water = 293 K, and water flow rate, Q w = 433 L/min.…”

Section: Methodsmentioning

confidence: 99%

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Numerical and Experimental Study on the Direct Chill Casting of Large-Scale AA2219 Billets via Annular Coupled Electromagnetic Field

et al. 2022

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The internal coupled electromagnetic melt treatment (ICEMT) method is firstly proposed to produce high-quality and large-sized aluminum alloy billets. A three-dimensional model was established to describe the ICEMT process of direct chill casting (DC casting). The effect of ICEMT on the fluid flow patterns and temperature field in the DC casting of ϕ880 mm AA2219 billets is numerically analyzed. Moreover, the mechanisms of the ICEMT process on grain refinement and macrosegregation were discussed. The calculated results indicate that the electromagnetic field appears to be coupled circinate at the cross section of the melt, the fluid flow becomes unstable accompanied by the bias flow, and the temperature profiles are significantly more uniform. An experimental verification was conducted and the results prove that compared with traditional direct chill casting, the microstructures of the AA2219 large-scale billet under the ICEMT process are uniform and fine.

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where,

, T sat = 363 K, T water = 293 K, and water flow rate, Q w = 433 L/min.…”

Section: Methodsmentioning

confidence: 99%

“…G.C. Nzebuka [ 17 ] used the low-Reynolds number turbulence model to study the thermal evolution in DC casting of an Al-4Cu alloy and concluded that the cooling conditions and casting speed similarly affected the sump depth and the melt penetration depth. D.G.…”

Section: Introductionmentioning

confidence: 99%

Numerical and Experimental Study on the Direct Chill Casting of Large-Scale AA2219 Billets via Annular Coupled Electromagnetic Field

et al. 2022

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“…The k-ζ-f model incorporates the near-wall turbulent anisotropy and non-local pressure-strain effects by introducing the wall-normal velocity fluctuation v 2 and the source term f as variables in addition to the turbulent kinetic energy and dissipation rate of the standard k-ε turbulence model. Hence, careful introduction of this kind of relaxation avoids the need for a damping function [46]. This model improves the numerical stability of the original v 2 -f model by solving the transport equation for the velocity scale ratio ζ = v 2 /k opposite to the velocity scale v2.…”

Section: Turbulence Modelmentioning

confidence: 99%

CFD Thermo-Hydraulic Evaluation of a Liquid Hydrogen Storage Tank with Different Insulation Thickness in a Small-Scale Hydrogen Liquefier

Jeong,

Lee,

Moon

2023

Fluids

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Accurate evaluation of thermo-fluid dynamic characteristics in tanks is critically important for designing liquid hydrogen tanks for small-scale hydrogen liquefiers to minimize heat leakage into the liquid and ullage. Due to the high costs, most future liquid hydrogen storage tank designs will have to rely on predictive computational models for minimizing pressurization and heat leakage. Therefore, in this study, to improve the storage efficiency of a small-scale hydrogen liquefier, a three-dimensional CFD model that can predict the boil-off rate and the thermo-fluid characteristics due to heat penetration has been developed. The prediction performance and accuracy of the CFD model was validated based on comparisons between its results and previous experimental data, and a good agreement was obtained. To evaluate the insulation performance of polyurethane foam with three different insulation thicknesses, the pressure changes and thermo-fluid characteristics in a partially liquid hydrogen tank, subject to fixed ambient temperature and wind velocity, were investigated numerically. It was confirmed that the numerical simulation results well describe not only the temporal variations in the thermal gradient due to coupling between the buoyance and convection, but also the buoyancy-driven turbulent flow characteristics inside liquid hydrogen storage tanks with different insulation thicknesses. In the future, the numerical model developed in this study will be used for optimizing the insulation systems of storage tanks for small-scale hydrogen liquefiers, which is a cost-effective and highly efficient approach.

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“…Luo et al [7] studied the micro segregation phenomenon during the formation of large sized AA2024 rolling ingot during the direct chill casting process through numerical simulations by employing a continuum mixture model. Nzebuka et al [18] reported enlargement of sump depth and reduction in the shell thickness of Al-Cu alloy ingot with the rise in casting speeds during direct chill casting. Pardeshi [19] developed a computational fluid dynamics model for thermal analysis, fluid flow analysis and to study solidification phenomenon during direct chill casting process.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of pull in control of rectangular AA1050 rolling ingot through the design of convex mould during direct chill casting process

Fegade,

Tated,

Nehete

2024

Eng. Res. Express

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The pull in effect / concavity on the lateral faces of the ingot is formed during solidification of the ingot due to the thermal stresses induced in the ingot. A part of rolling ingots with pull in effect are cut by conventional cutting process which affects the recovery and increases wastage and cost of production. In the present work, an elemental death and birth technique was used to develop a numerical model to study mechanical and thermal behavior during solidification of AA1050 rolling ingot. The results of the model are validated with results of Williams model available in the literature. Furthermore, different mould designs provided with convexity on lateral surfaces with convexity radius of 16 mm to 26 mm were numerically analyzed. A series of numerical simulations were conducted with varying mould convexity with increment value of one. The results revealed that, providing convexity to the mould is an effective method to control the pull in effect during direct chill casting process. The convexity radius of 26 mm is enough to completely eliminate the pull in radius of 23.34 mm for the rectangular AA1050 ingot.

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Thermal evolution in the direct chill casting of an Al-4 pct Cu alloy using the low-Reynolds number turbulence model

Cited by 15 publications

References 22 publications

Numerical and Experimental Study on the Direct Chill Casting of Large-Scale AA2219 Billets via Annular Coupled Electromagnetic Field

Numerical and Experimental Study on the Direct Chill Casting of Large-Scale AA2219 Billets via Annular Coupled Electromagnetic Field

CFD Thermo-Hydraulic Evaluation of a Liquid Hydrogen Storage Tank with Different Insulation Thickness in a Small-Scale Hydrogen Liquefier

Numerical investigation of pull in control of rectangular AA1050 rolling ingot through the design of convex mould during direct chill casting process

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