Yazar "Mat, Mahmut Dursun" seçeneğine göre listele

Listeleniyor 1 - 6 / 6
  • Küçük Resim
    Öğe
    A three-dimensional mathematical model for absorption in a metal hydride bed
    (2002) Aldaş, Kemal; Mat, Mahmut Dursun; Kaplan, Yüksel
    Heat and mass transfer, fluid flow and chemical reactions in a hydride bed are numerically investigated with a general purpose PHOENICS code. Hydride formation takes place faster near the cooled boundary walls and slower around the core region of the bed. It is found that fluid flow affects the temperature distribution in the system, however, it does not significantly improve the amount of hydrogen absorbed.
  • Küçük Resim
    Öğe
    A two-phase flow model for hydrogen evolution in an electrochemical cell
    (2004) Mat, Mahmut Dursun; Aldaş, Kemal; Ilegbusi, Olusegun Johnson.
    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.
  • Küçük Resim
    Öğe
    Experimental and numerical investigation of effect of particle size on particle distribution in particulate metal matrix composites
    (2006) Mat, Mahmut Dursun; Aldaş, Kemal
    The effect of particle size on particle distribution during the casting of particulate metal matrix composites (PMMC) is experimentally and numerically investigated. Pb20% Sn alloy and Zr2O3 particles are employed as matrix and reinforcing materials respectively. The casting is performed with an inert gas pressure. The final product is sectioned at several locations and particle fraction is determined using image processing software. Particle fraction is numerically determined by following trajectories of selected particles. It is found that particle fraction decreases along the mold and segregation is reduced with larger particles. The numerical results agree reasonable with experimental data.
  • Küçük Resim
    Öğe
    Experimental and theoretical analysis of particle distribution in particulate metal matrix composites
    (2005) Aldaş, Kemal; Mat, Mahmut Dursun
    Particle distribution in particulate metal matrix composites was investigated experimentally and theoretically. SiC reinforced Pb 20%Sn alloy mechanically was stirred and cast into a cylindrical mold by an inert gas pressure. Particle distribution in the cast is determined at several locations by sectioning and microscopic investigation techniques. The particle fraction is found to decrease along the axis of the mold. The regions close to the boundary wall are determined as the possible clustering areas. A mathematical model is developed to characterize flow of mixture of molten metal alloy and ceramic particles. The distribution of particles is estimated from the trajectories of representative particles with the Lagrangian point of view. The numerical results are reasonably suited with experimental data.
  • [ X ]
    Öğe
    Numerical analysis of hydrogen storage in metal-hydride beds
    (2002) Aldaş, Kemal; Mat, Mahmut Dursun
    In this study, hydrogen absorption in a metal-hydride bed is numerically investigated. The mathematical model considers the heat and mass transfer and the chemical reaction that take place during the absorption. The hydride bed heats up due to the exothermic reaction. Numerical results show that hydrogen absorption is completed faster near the cooled wall, while it takes longer at the center. Hydriding processes are investigated with the temperature histories, H/M ratio and temperature distributions at several locations in the tank. The estimated H/M ratio is found to agree satisfactorily with the experimental data in the literature.
  • [ X ]
    Öğe
    Numerical investigation of subcooled boiling in a vertical pipe using a bubble-induced turbulence model
    (2002) Mat, Mahmut Dursun; Aldaş, Kemal; Kaplan, Yüksel
    A bubble-induced turbulence model is applied to subcooled boiling of water in a vertical pipe. The volume fractions, velocities, temperatures of water and steam and turbulence characteristics of the flow are estimated in a range of heat fluxes, subcooling temperatures and outlet pressures. The mathematical model involves solutions of transport equations for the variables of each phase with allowance for interphase transfer of momentum and energy. The numerical results agree satisfactorily with those of experimental and numerical results in the literature.