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DTIC ADA221599: Buoyant Convection in Dendritic Solidification |
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by Defense Technical Information Center |
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In solidification, when the process is limited by |
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diffusion of released latent heat or solute, often the |
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two-phase interface forms finger-like shapes called |
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dendrites, whose tips are nearly paraboloidal in form. |
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For a pure material solidifying into an undercooled melt, |
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if surface energy and gravity are negligible, a well- |
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known solution due to Ivantsov (1947) describes the |
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steady growth with a paraboloidal interface. We construct |
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a regular perturbation to this solution for a downward |
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growing axisymmetric dendrite, based on the smallness of |
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a buoyancy parameter G, to examine the effects of buoyant |
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flow on the solidification. The analytic solution |
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predicts that generally the buoyancy enhances growth and |
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changes the shape of the interface, giving a sharper tip |
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and wider base. These effects depend strongly on the |
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Prandtl number, and also on the Stefan number |
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(undercooling). The results compare will with the |
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experiments of Huang and Glicksman (1981) up to G 5000, |
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but over predict convective effects for higher G. |
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Date Published: 2018-02-26 00:55:15 |
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Identifier: DTIC_ADA221599 |
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Item Size: 22490558 |
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Language: english |
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Media Type: texts |
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# Topics |
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DTIC Archive; Canright, David; NAVAL ... |
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@chris85 |
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