The trajectories and distribution of particles in a turbulent axisymmetric gas jet injected into a flash furnace shaft
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INTRODUCTION
IN the flash-smelting process, fine particles of sulfide concentrates and flux are injected with oxygen-enriched air into the furnace. The major component of the process is the furnace shaft in which sulfur is removed by oxidation of the mineral particles in a turbulent gas jet. Therefore, it is important to understand better the subprocesses taking place in such a gas jet. The mathematical modeling of the particle-laden turbulent flows in confined systems has been a difficult problem not only due to the difficulties in solving the nonlinear elliptic partial differential governing equations but also due to the difficulties associated with mathematical description of complex turbulent characteristics of the interaction between the dispersed particle phase and the continuous fluid phase. Crow et al. I~l analyzed gas-droplet flows by accounting for the mass, momentum, and energy coupling between phases. They developed the particle-source-in-cell (PSICELL) model to predict the behavior of the particle-laden turbulent system. Spalding I2'3J developed numerical procedures for multiphase flows. Melville and Bray I41studied the turbulent two-phase jet and proposed a correlation to describe the effect of the presence of particles on turbulence by using the ratio of the mean particle bulk density to the mean gas density. Elghobashi and Abou-Arab I51 developed a two-equation turbulence model for two-phase flows. They derived the equations of the turbulent kinetic energy and the rate of its dissipation using third-order correlations involving fluctuating components of variables. They compared model predictions of the particle-laden jet in a vertical cylindrical system with experimental data and obtained good agreement) 5'61 However, they mentioned that more tests are required to establish the universality of the coefficients used in their correlations. I5'61 Smoot and coworkers 17-~61have extensively investigated two-phase turbulent jets in confined systems such as pulverized-coal
Y. B. HAHN, Graduate Student, and H. Y. SOHN, Professor, are with the Department of Metallurgy and Metallurgical Engineering, University of Utah, Salt Lake City, UT 84112-1183. Manuscript submitted July 10, 1987. METALLURGICALTRANSACTIONS B
combus~:ors in terms of both experimental and modeling efforts. Weber e t a / . [171did simulation work on the dispersion of heavy particles in a confined flow. They neglected all exteraal forces except for the drag force. Since its development by Outokumpu Oy and INCO in the late 1940's and early 1950's, the flash-smelting process has been a dominant process for smelting various sulfide minerals, including those of copper and nickel. The attractiveness of the flash-smelting process has greatly increased with the increasing availability of inexpensive tonnage oxygen and because of major advantages of substantial reduction in fuel requirement, efficient sulfur dioxide recovery, and rapid smelting rates. In spite of the increasing industrial stature cf the flash-smelting process, it is only in re
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