Open Access

ARTICLE

Y.R. Li¹, L. Peng¹, W.Y. Shi¹, N. Imaishi²
FDMP-Fluid Dynamics & Materials Processing, Vol.2, No.3, pp. 153-166, 2006, DOI:10.3970/fdmp.2006.002.153
Abstract The convective instabilities in semiconduc-tor or oxide melts, significantly affect the quality oflarge crystals grown from the melts by the Czochralskimethod. This paper reviewsour recent numerical stud-ies of thermal convection in annular pools of low-Pr sili-con melt and moderate-Pr silicone oil. The mechanismsof the convective instability are discussed and the criticalconditions for the onset of three-dimensional flow are de-termined. The results show that the hydrothermal wave,characterized by curved spokes, is dominant in a shallowthin pool. In a thick pool of the low-Pr silicon melt, thereappears a standing wave type of oscillatory longitudinalrolls, which moves in the azimuthal More >

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ARTICLE

Koichi Kakimoto, Lijun Liu
FDMP-Fluid Dynamics & Materials Processing, Vol.2, No.3, pp. 167-174, 2006, DOI:10.3970/fdmp.2006.002.167
Abstract This paper deals with the investigation of the flow instability of molten silicon in a magnetic field during crystal growth by means of the Czochralski method. The flow exhibits a three-dimensional structure due to a transverse non-axisymmetric pattern of the magnetic field. The melt-crystal interface is found to be nearly two-dimensional. The azimuthal non-uniformity of the temperature field is much weaker on the crystal and crucible sidewalls in the case of high rotation rates of crucible and crystal than in the case of non-rotating crucible and crystal. More >

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1160

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T. J. Jaber¹, M. Z. Saghir¹
FDMP-Fluid Dynamics & Materials Processing, Vol.2, No.3, pp. 175-190, 2006, DOI:10.3970/fdmp.2006.002.175
Abstract The study deals with three-dimensional numerical simulations of fluid flow and heat transfer under the effect of a rotating magnetic field (RMF) during the growth of Ge_0.98Si_0.02 by the traveling solvent method (TSM). By using a RMF, an attempt is made to suppress buoyancy convection in the Ge_0.98Si_0.02 solution zone in order to get high quality and homogeneity with a flat growth interface. The full steady-state Navier-Stokes equations, as well as the energy, mass transport and continuity equations, are solved numerically using the finite element method. Different magnetic field intensities (B=2, 4, 10, 15 and 22 More >

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1071

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E. A. Semma¹, M. El Ganaoui², V. Timchenko³, E. Leonardi³
FDMP-Fluid Dynamics & Materials Processing, Vol.2, No.3, pp. 191-202, 2006, DOI:10.3970/fdmp.2006.002.191
Abstract This paper deals with the investigation of thermovibrational convection induced by harmonic oscillations of the temperature boundary conditions related to the hot wall in a Bridgman-like (VB) geometrical configurations. Two different models of the VB configuration are considered (a simplified version referred to as "restricted" model and a more realistic and complete model with phase change allowed). The effects of temperature modulation are considered for both models and with regard to several possible initial (basic) states (stationary and oscillatory). In the restricted fluid cavity, we identify the existence of a critical frequency minimizing the flow More >

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ARTICLE

V.G. Kozlov^1,2, A.A. Ivanova³, P. Evesque¹
FDMP-Fluid Dynamics & Materials Processing, Vol.2, No.3, pp. 203-210, 2006, DOI:10.3970/fdmp.2006.002.203
Abstract Sedimentation of granular matter in a vertical channel filled with a viscous liquid and subject to longitudinal translational vibration is studied, starting froma compact suspension. A new vibrational effect is foundexperimentally and described theoretically; it is the formation of blocks (with a relatively high density) of sedimenting granular matter with stable lower and upper horizontal demarcations and a sharp density discontinuity. Owing to this phenomenon the sedimentation velocity of such granular matter is reduced. A new theoreticalmodel based on viscous vibrational particle interactionin the limit of concentrated suspensions is elaborated, assuming particle-particle attraction in direction More >

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1135

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E. Abhilash¹, M.A. Joseph¹, Prasad Krishna¹
FDMP-Fluid Dynamics & Materials Processing, Vol.2, No.3, pp. 211-220, 2006, DOI:10.3970/fdmp.2006.002.211
Abstract Aluminium-Silicon alloys are in high de-mand as an engineering material for automotive,aerospace and other engineering applications. Mechanical properties of Al-Si alloys depend not only on chemical composition but also more importantly on microstructural features such as dendritic alpha-aluminiumphase and eutectic silicon particles. As an additive to Al-Si alloys, sodium improves mechanical properties byforming finer and fewer needles like microstructures.Thus, prediction of the macro and microstructures obtained at the end of the solidification is of great interest for the manufacturer of aluminium alloys. Neuralnetworks are sophisticated nonlinear regression routinesthat, when properly “trained”, allow for the identificationof More >

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