Yazar "Ilegbusi, OJ" seçeneğine göre listele

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    A review of the modeling of multi-phase phenomena in materials processing - I. Solid-liquid systems
    (TECHNOMIC PUBL CO INC, 2000) Ilegbusi, OJ; Mat, MD
    This paper reviews the modeling of multiphase flow phenomena in liquid-solid materials processes. Three mathematical models are discussed, namely, two-phase, continuum-mixture and multi-domain models. Scaling and analytical solutions of the governing equations are given for some simplified situations. A linear stability analysis is also presented on convection in the mushy region in alloy solidification.
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    A two-phase flow model for hydrogen evolution in an electrochemical cell
    (PERGAMON-ELSEVIER SCIENCE LTD, 2004) Mat, MD; Aldas, K; Ilegbusi, OJ
    Hydrogen evolution, flow field and current density distribution in an electrochemical cell are investigated with a two-phase flow model. The mathematical model involves solutions of transport equations for the variables of each phase with allowance for inter-phase transfer of mass and momentum. The buoyancy force generated due to density difference between two phases modifies flow profile and increases fluid velocity at the vicinity of the electrode. The current density decreases over the electrode mainly because of the decrease in effective conductivity of electrolyte. It is found that the hydrogen generation significantly increases at higher electrolyte flow by reducing the residence time of bubbles over the electrode. The predicted results satisfactorily agree with data available in the literature. (C) 2003 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.
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    Application of a hybrid model of mushy zone to macrosegregation in alloy solidification
    (PERGAMON-ELSEVIER SCIENCE LTD, 2002) Mat, MD; Ilegbusi, OJ
    Solidification of an aqueous ammonium chloride (NH4Cl-H2O) solution inside a two-dimensional cavity is numerically investigated using a continuum mixture mathematical model. The mushy region where solid and liquid phases co-exist is considered a non-Newtonian fluid below a critical solid fraction, and a porous medium thereafter. This critical solid fraction is chosen as that corresponding to the coherency point, where a solid skeleton begins to form. The numerical results show that the solidification of a hypereutectic NH4Cl-H2O solution is mainly characterized by the rejection of solute at the mushy region and double diffusive convection induced by the opposing solutal and thermal buoyancy forces. The mathematical model agrees satisfactorily with the available experimental and numerical data. (C) 2001 Elsevier Science Ltd. All rights reserved.
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    Prediction of macrosegregation in binary alloy solidification using a non-newtonian mushy model
    (TECHNOMIC PUBL CO INC, 2000) Mat, MD; Ilegbusi, OJ
    The solidification of Sn-10%Pb alloy and subsequent macrosegregation patterns are numerically investigated with a continuum mixture model. The mathematical model is valid in the solid, mushy (solid + liquid) and liquid regions. A hybrid flow model is employed for the mushy region. This model assumes the mushy region behaves as a non-Newtonian fluid below a transitional solid fraction and as a porous medium thereafter. The positive and negative segregations formed during the solidification are successfully predicted.