Multiparticle interfacial drag in equiaxed solidification

Wang, C. Y.; Ahuja, Sandeep; Beckermann, C.; Groh, H. C. De

doi:10.1007/bf02648984

Cited by 91 publications

(49 citation statements)

References 20 publications

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“…Wang et al examined the permeability of equiaxed structures in the mid 1990s, finding that fluid drag was a function of various terms including arm spacings and grain densities, but recently this complex subject appears to have received little attention. 185) It is evident that an improved understanding of grain growth and motion in a convecting melt would only better the predictive power of multi-phase models. 101) …”

Section: The Permeability Problemmentioning

confidence: 99%

Macrosegregation in Steel Ingots: The Applicability of Modelling and Characterisation Techniques

Pickering

2013

ISIJ Int.

146

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The macro-scale segregation of alloying elements during the casting continues to afflict the manufacturers of steel ingots, despite many decades of research into its prediction and elimination. Defects such as A-segregates are still commonplace, and components are regularly scrapped due to their presence, leading to increased economic and environmental costs. With the growth of the nuclear power industry, and the increased demands placed on new pressure vessels, it is now more important than ever that today's steel ingots are as chemically homogeneous as possible.This article briefly reviews the development of our current understanding of macrosegregation phenomena during the 20 th century, before going on to assess the latest developments in the field of macrosegregation modelling. The aim of the text is to highlight the shortcomings of applying contemporary macromodels to steel-ingot casting, and to suggest practical alternatives. In addition, the experimental characterisation of macrosegregation is explored, and a review of the various techniques currently available is presented.

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Section: The Permeability Problemmentioning

confidence: 99%

Macrosegregation in Steel Ingots: The Applicability of Modelling and Characterisation Techniques

Pickering

2013

ISIJ Int.

146

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“…The EPMA was performed using wavelength dispersive X-ray spectroscopy on an ARL SEMQ electron microprobe. A linear traverse of the probe of 20 mm steps down the middle of the ingot was used, with the mean atomic number (MAN) background correction and the following MAN standards and Z-bars for the calibration curve: SiC (11.6), Si (14), Ti (22), Fe (26), Co (27), Ni (28), and Zn (30). A detailed discussion of the microprobe procedures can be found in Refs.…”

Section: Segregation Measurementsmentioning

confidence: 99%

“…An understanding of this settling behavior is necessary for the understanding and possible control of the solidification process. The basic settling characteristics of manufactured dendritic shapes and natural dendrites in clear metal analogs have been examined by: Zakhem et al [10], Ahuja [11], Ahuja et al [12], de Groh III et al [13], and Wang et al [14]. These studies have resulted in the determination of the interfacial drag between equiaxed dendrites and the melt over a wide range of solid volume fractions.…”

Section: Introductionmentioning

confidence: 99%

Effect of melt convection and solid transport on macrosegregation and grain structure in equiaxed Al–Cu alloys

Rerko

Groh

Beckermann

2003

Materials Science and Engineering: A

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Macrosegregation in metal casting can be caused by thermal and solutal melt convection, and the transport of unattached solid crystals. These free grains can be a result of, for example, nucleation in the bulk liquid or dendrite fragmentation. In an effort to develop a comprehensive numerical model for the casting of alloys, an experimental study has been conducted to generate benchmark data with which such a solidification model could be tested. The specific goal of the experiments was to examine equiaxed solidification in situations where sinking of grains is (and is not) expected. The objectives were: (1) experimentally study the effects of solid transport and thermosolutal convection on macrosegregation and grain size distribution patterns; and (2) provide a complete set of controlled thermal boundary conditions, temperature data, segregation data, and grain size data, to validate numerical codes. The alloys used were Al Á/1wt.% Á/Cu, and Al Á/10wt.% Á/Cu with various amounts of the grain refiner TiB 2 added. Cylindrical samples were either cooled from the top, or the bottom. Several trends in the data are apparent and provide good starting points for comparisons to numerical models. #

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“…Mathematically, this S M term arises from the dissipative interfacial stress during the volume averaging process [28], and is modelled as a momentum sink term using a knowledge of the permeability of the porous medium [29]. Diverse modelling approaches to deal with such a permeability tensor have been studied in research on porous media [30][31][32]. In this study we represent it as a type of Carman-Kozeny permeability tensor [33].…”

Section: Governing Equationsmentioning

confidence: 99%

Numerical study of melting of a phase change material (PCM) enhanced by deformation of a liquid–gas interface

Kim

Hossain

Nakamura

2013

International Journal of Heat and Mass Transfer

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Numerical simulations are performed in order to examine the time-dependent melting, and heavily deforming processes of phase change material (PCM) subjected to local heating. By comparing cases with and without deformation, the impact of the inclusion of a deformation model is firstly addressed to understand what influences the precise melting behavior. Mass, momentum and energy conservation equations are solved in a 2-D system based on a fixed grid by means of a finite volume method. The Volume of Fluid (VOF) method and the Enthalpy-Porosity method are applied to model the deformable liquid-gas interface and the melting processes, respectively. Results successfully show the melting, subsequent deformation and dropping-off behavior of the molten PCM. It is found that the inclusion of the deformation model enhances the melting owing to the increase of the total received heat; namely, widening of the contact area at the melting front and induced flow motion inside molten PCM improve the heat transfer toward the melting front. Parametric studies by varying the applied Stefan number so as to change the surface tension are also made to ensure the above-mentioned enhancement mechanism is universally applicable.

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Multiparticle interfacial drag in equiaxed solidification

Cited by 91 publications

References 20 publications

Macrosegregation in Steel Ingots: The Applicability of Modelling and Characterisation Techniques

Macrosegregation in Steel Ingots: The Applicability of Modelling and Characterisation Techniques

Effect of melt convection and solid transport on macrosegregation and grain structure in equiaxed Al–Cu alloys

Numerical study of melting of a phase change material (PCM) enhanced by deformation of a liquid–gas interface

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