Investigation of macrosegregation for different dendritic arm spacing, casting temperature, and thermal boundary conditions in a direct-chill casting

Waheed, M. A.; Nzebuka, Gaius Chukwuka

doi:10.1007/s00339-020-03920-9

Cited by 12 publications

(5 citation statements)

References 27 publications

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“…This results in deeper melt penetration as a consequence of the deepening of the liquid sump length, the slurry, and mushy zones widen toward the central region for the higher Pe. Similar observations have been reported in [1,2] for HDC casting and in [9][10][11][12][13][14]33] for VDC casting at higher casting speeds. This reveals that heat extraction from the molds and solidification rate are lower for the higher Pe than the lower Pe.…”

Section: Pesupporting

confidence: 87%

“…The drag forces acting to dampen the fluid flow in the mushy region are embodied by the third term on the RHS of Equation ( 2), and the term µ K can be represented as suggested in [14].…”

Section: Description Of the Mushy And Slurry Zonementioning

confidence: 99%

“…Recently, researchers [2,[8][9][10][11][12][13][14][15] have numerically simulated the VDC casting (HDC casting has received less attention) via the low-Reynolds number kinetic energy (k)-energy dissipation rate (ε) (low-Re kε) and velocity variance-elliptic relaxation (v 2 − f or V2F) turbulence model. The V2F turbulence model consists of four equations, the standard k and ε equations, and the additional v 2 and f equations.…”

Section: Introductionmentioning

confidence: 99%

“…The V2F turbulence model consists of four equations, the standard k and ε equations, and the additional v 2 and f equations. The addition of v 2 and f is to handle the anisotropic wall-blocking effect, thereby acting as a natural damper closed to the walls [14]. It has been reported that the agitation of the liquid melt, as a result of turbulence eddies, can change the solidification interfaces [14].…”

Section: Introductionmentioning

confidence: 99%

“…The addition of v 2 and f is to handle the anisotropic wall-blocking effect, thereby acting as a natural damper closed to the walls [14]. It has been reported that the agitation of the liquid melt, as a result of turbulence eddies, can change the solidification interfaces [14]. Few researchers have numerically investigated flow and temperature distribution in HDC casting.…”

Section: Introductionmentioning

confidence: 99%

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Prediction of Limiting Casting Speed in a Horizontal Direct-Chill Casting through Numerical Modeling and Simulation

Ufodike

Nzebuka

Egole

2023

Metals

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Limiting casting expression speed was obtained and the flow redistribution and thermal history in a horizontal direct-chill (HDC) casting was predicted using the numerical modeling approach. The governing solidification equations were non-dimensionalized to understand the relevant contribution of each term in the solidification processes in the HDC system. The effect of an increase in the casting speed on the flow characteristics and sump length was represented by the Péclet number Pe. Details of the simulation reveal that at a low Pe, the natural convective flow creates minor counter-clockwise recirculating cells in the lower half of the HDC domain. However, at a Pe above 82.75, the minor recirculating cells disappear due to the strong forced convective flow from the upstream. Additionally, an increase in the Pe increases the sump length, strength, and spread of the turbulence field within and beyond the mold region. The limiting casting conditions are computed by predicting the sump length over which the alloy temperature is above the solidus temperature. This gives a simple relation for the casting speed as a function of the geometrical data and the alloy properties. The current work is useful to casting engineers who always rely on trial and error in choosing a new casting speed whenever a new alloy is to be produced. Hence, with the new information and the casting speed relations, it is possible and easy to predict the operating window over which melt break-out can occur during HDC.

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Section: Pesupporting

confidence: 87%

“…The drag forces acting to dampen the fluid flow in the mushy region are embodied by the third term on the RHS of Equation ( 2), and the term µ K can be represented as suggested in [14].…”

Section: Description Of the Mushy And Slurry Zonementioning

confidence: 99%