Effect of computational domain size on the mathematical modeling of transport processes and segregation during directional solidification

Frueh, C.; Poirier, D. R.; Felicelli, Sergio D.

doi:10.1007/s11661-000-0092-4

Cited by 8 publications

(8 citation statements)

References 17 publications

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“…Consequently, control of the as-cast microstructure is of great importance. Although the development of as-cast grain structures has been of interest for many decades, various studies aimed at modeling the formation of solidification structures in a wide range of alloy systems and casting processes have highlighted the complexity associated with simulating the various intrinsic and extrinsic parameters that influence the solidification process [18][19][20][21][22][23][24][25] . Moreover, solidification parameters operate over multiple lengthscales, spanning the atomic scale for grain refinement, the micronscale during the formation of the dendritic structure to the macroscopic scale for convective fluid flow phenomena.…”

Section: Discussionmentioning

confidence: 99%

Linking the Properties, Processing and Chemistry of Advanced Single Crystal Ni-Base Superalloys

Tin

Zhang

Hobbs

et al. 2008

Superalloys 2008 (Eleventh International Symposium)

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As nickel-base single crystals are being implemented in gas turbine engines operating at temperatures in excess of 1600K, maintaining structural properties at these elevated temperatures has become an increasingly important problem. Typically, elevated levels refractory alloying elements are added to these single crystal alloys to enhance the degree of solid solution strengthening within the microstructure. The presence of Re, W, Mo, Ta in Ni-base superalloys strongly influences parameters, such as the stacking fault energies, lattice misfit, and shear modulus of the crystalline lattices, that govern the creep response of the material. However, this is a challenge when dealing with high refractory alloys that are susceptible to the precipitation of deleterious topologically-close-packed (TCP) phases. Recent investigations have demonstrated Ru additions to be beneficial with respect to hindering the formation of these TCP phases and consequently improving the creep properties of these advanced single crystal alloys. Substantial effort has been dedicated towards understanding the fundamental effects and the mechanisms by which Ru additions alter the structure of the γ and γ' phases. Much of this knowledge has been effectively applied to the development of a new class of single crystal Ni-base superalloys with improved strength and a temperature capability significantly higher than those of existing "second" or "third" generation alloys. Nevertheless, optimization of the alloy chemistries remains notoriously difficult as various component design requirements related to the solidification characteristics, overall blade density, coating compatibility and cost must also be carefully considered when developing these materials. This investigation addresses some of the issues associated with the development of Ru-bearing, high refractory content Ni-base superalloys and describes how interrelationships between the properties, processing, microstructure and chemistry of these alloys can be balanced to yield a practical "fourth" generation single crystal superalloy.

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Section: Discussionmentioning

confidence: 99%

Linking the Properties, Processing and Chemistry of Advanced Single Crystal Ni-Base Superalloys

Tin

Zhang

Hobbs

et al. 2008

Superalloys 2008 (Eleventh International Symposium)

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“…In order to resolve the formation of freckle defects the computational domain should be discretized with elements that are smaller than d 1 and D/V in the horizontal and vertical directions, respectively [20]. Also, the minimum liquid layer height required for freckle formation is only twice the height of the mushy zone, according to Frueh et al [33]. Applying these criteria, we have used a 400 × 30 grid system.…”

Section: Numerical Proceduresmentioning

confidence: 99%

Role of plume convection and remelting on the mushy layer structure during directional solidification

Jain¹,

Kumar²,

Dutta³

2007

J. Phys. D: Appl. Phys.

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In the present work, solidification of a hyper-eutectic ammonium chloride solution in a bottom-cooled rectangular cavity (i.e. with stable thermal gradient) is numerically simulated. The role of finger convection and remelting on the structure of a mushy layer containing channels is studied. The numerical simulation is performed using a fixed-grid single-domain approach in which local remelting and anisotropic variation of mush permeability are taken into account. It is observed that solute-rich liquid rising in the form of finger convection causes delayed growth and localized remelting of portions of the solid/mush interface, resulting in patches of thin structure known as channels. The present study reveals the manner in which the structure of a mushy layer evolves during channel formation. Effects of bulk liquid convection on channel formation, evolution, destruction and the resulting effect on the mush structure are found to be significant. Numerical prediction with regard to variation of the number of channels with time agrees qualitatively with published experimental results.

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“…The numerical studies developed from 2D simulation to 3D simulation and from binary components to multiple components. Since appropriate mesh spacing is important to the accuracy of numerical simulation results, the studies about more detailed mesh spacing sensitivity had also been investigated by Frueh and Sung …”

Section: Introductionmentioning

confidence: 99%

The Effect of Static Magnetic Field on the Channel Formation during Directional Solidification of Aqueous Ammonium Chloride Solution

Ding

Tao

Ren

et al. 2018

Crystal Research and Technology

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This study investigates the effect of magnetic field on the channel formation by using a 27 wt.% aqueous ammonium chloride solution at an initial base temperature of 246 K (−27°C) under magnetic fields of 0.03T, 0.05T, and 0.1T. The application of a magnetic field suppresses channel formation, as reflected by the delayed occurrence, the decreased number and density of channels, and the increased areas with no channels and mushy-zone height necessary to form channels. The suppression of channel formation is caused by the magnetohydrodynamic (MHD) effect on convection during directional solidification. The higher temperature gradient in the mushy zone under an applied magnetic field further confirms the mechanism. The present investigation would help to provide useful predictions for the influence of magnetic field on channel formation during the directional solidification of alloys.

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Effect of computational domain size on the mathematical modeling of transport processes and segregation during directional solidification

Cited by 8 publications

References 17 publications

Linking the Properties, Processing and Chemistry of Advanced Single Crystal Ni-Base Superalloys

Linking the Properties, Processing and Chemistry of Advanced Single Crystal Ni-Base Superalloys

Role of plume convection and remelting on the mushy layer structure during directional solidification

The Effect of Static Magnetic Field on the Channel Formation during Directional Solidification of Aqueous Ammonium Chloride Solution

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