Browsing by Author "Bahloul, D."

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    Numerical Investigation Of Three-dimensional Heat Transfer And Natural Convection In The Sapphire Melt For Czochralski Growth Process
    (Oum-El-Bouaghi University, 2018) Azoui, Hanane; Soltani, N.; Bahloul, D.
    A three-dimensional numerical study of the convection heat transfer in a simulated Czochralski system is conducted .In this work, the numerical investigation were performed to analyze the free convection in the Czochralski crucible and the temperature fluctuations(thermal instabilities) just below the melt-crystal interface. We used the Finite Volume Method in cylindrical coordinates and the Fast Fourier Transform method for study the free convection, the temperature fluctuations 2 mm near the interface by taking into account the case of non-rotating crystal. In this study the heat transfer, thermal instabilities, melt natural convection, radiative heat transfer, Marangoni convection were conducted for Al2O3 melt in the crucible. Our objective is to show the fluctuations of temperature just below the interface by taking into account the effect of Rayleigh number for determining the crucible heating temperature value, and display the problem and his solution of the natural convection in the Czochralski crucible.
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    Numerical Simulation Of The Imulation Crystal Rystal Growth Of Ti:al Rowth Al2o3 Material By The µ -pd Technology
    (Oum-El-Bouaghi University, 2016) Azoui, H.; Laidoune, A.; Haddad, D.; Bahloul, D.; Merrouchi, F.
    In this work we have studied the growth of titanium doped sapphire using the micro-pulling down technique; we established a numerical, two-dimensional finite volume model in cylindrical coordinates with an axisymmetric configuration. The flow, the heat and the mass transfer are modeled by the differential equations of conservation of mass, momentum, energy and species. This problem, which takes into account the convection-diffusion coupling, is discretized using the Finite Volumes Method. Simulation results show that the longitudinal distribution of titanium remains homogeneous along the axis of the sapphire material. The radial mass transfer of titanium increases in the crystal when the pulling rate increases. This important result contributes to strengthen the coupling of the laser beam with the active ions and allows a highest laser output power. The melt/crystal interface for the µ-PD technique has a flat shape; this flatness of the interface shape agrees with the experiment observation and is very important since it shows that drawing conditions are very stable. Our model for the µ-PD method is in good agreement with experimental results.