Sedimentation speed of a free dendrite growing in an undercooled melt

Mirihanage, Wajira; Browne, David J.

doi:10.1016/j.commatsci.2010.08.013

Cited by 8 publications

(1 citation statement)

References 20 publications

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“…to estimate the settling velocity of an isolated equiaxed dendrite in a viscous fluid at a moderate Reynolds number region (1 ≤ Re ≤ 100) by using a drag coefficient corrected with the Reynolds number and a factor introduced to account for the effect of shape on drag forces. [13] However, they ignored a more important fact that confining walls or finite boundaries exerted a great extra retardation force on freely equiaxed dendrites settling in a vessel filled with fluid. The retardation effect of the wall on drag force should have been taken into account.…”

Section: Introductionmentioning

confidence: 99%

Settling velocity of equiaxed dendrites in a tube

2013

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The settling velocity of equiaxed dendrites can cause macrosegregation and influence the structure of the equiaxed zone during the casting solidification process. So an understanding of the settling characteristics is needed to predict the structure and segregation in castings. The settling velocity of NH4Cl equiaxed dendrites of non-spherical geometry was studied experimentally in an NH4Cl–70wt.%H2O solution. A calculation formula was proposed to calculate the settling velocity of sediment equiaxed dendrites in a tube filled with saturated solution at a moderate Reynolds number region. The retardation effects of the wall and morphology of the equiaxed dendrite on the settling velocity were taken into account in the development of the calculation formula, and the correction function B of the drag coefficient with consideration of the retardation effects of the wall and morphology of the equiaxed dendrite on the settling velocity of the equiaxed dendrite was calibrated according to the experimental results. A comparison showed that the formula has a good accordance with the experimental results.

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Section: Introductionmentioning

confidence: 99%

Settling velocity of equiaxed dendrites in a tube

2013

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Effects of Gravity on the Columnar to Equiaxed Transition in Directional Solidification

Mirihanage¹,

Browne²

2011

Shape Casting

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Computational Modeling of Columnar to Equiaxed Transition in Alloy Solidification

Mirihanage¹,

Dai²,

Dong³

et al. 2012

Adv Eng Mater

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The columnar to equiaxed transition (CET) provides a challenging simulation goal for computational models of alloy solidification, in addition to being an important technological feature of many casting processes. CET thus provides an industrially relevant test‐case for those developing numerical models across a range of scales. Whether or not CET occurs depends on numerous experimental parameters such as cooling rate, speed of columnar growth, thermal gradient in the liquid, and level of grain refiner in the alloy. Information on columnar and equiaxed grain structure, and the transition between the two, is very useful for foundry engineers, at the macroscopic scale of the casting. The detailed microstructure within each grain is determined by typically dendritic growth and local transport of solute and heat. This paper presents a review of recent progress on modeling CET at multiple length scales. It is evident that, whilst micro‐models can provide simulations of physical phenomena, such as the evolution of dendrite morphology, at scales 10−3 to 10−5 m, finite computational resources preclude this resolution over the length scale of castings which is in the 10−2–100 m range. Instead, reasonably accurate models of CET formation in castings can be achieved by meso‐scale modeling featuring 10−3–10−2 m phenomena. Such meso‐scale models make use of analytical expressions to simulate dendrite growth in undercooled melts. Recent progress in modeling of CET, at both macro/meso‐ and micro‐scales is reviewed, and computational challenges yet to be met are summarized.

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Sedimentation speed of a free dendrite growing in an undercooled melt

Cited by 8 publications

References 20 publications

Settling velocity of equiaxed dendrites in a tube

Settling velocity of equiaxed dendrites in a tube

Effects of Gravity on the Columnar to Equiaxed Transition in Directional Solidification

Computational Modeling of Columnar to Equiaxed Transition in Alloy Solidification

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