توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Computer Simulation of Particle Size Classification in Air Separators
نویسنده(ها): ، ،
اطلاعات انتشار: Iranian Journal of Chemistry and Chemical Engineering (IJCCE)، بيست و هشتم،شماره۴(پياپي ۵۲)، ۲۰۰۹، سال
تعداد صفحات: ۸
Cement powder size classification efficiency significantly affects quality of final product and extent of energy consumption in clinker grinding circuits. Static and dynamic or high efficiency air separators are being used widely in closed circuit with multi–compartment tube ball mills, High Pressure Grinding Rolls (HPGR) and more recently Vertical Roller Mills (VRM) units in cement plants to classify comminuted clinker particles at finish grinding stage. Therefore, simulation of air separators is of critical importance in order to provide tools that can assist cement plants engineers in their routine clinker grinding circuit optimization efforts. In this paper, Air Separator Simulator (ASSIM), a newly developed simulator implemented in VB™ which provides a user–friendly process analysis and optimization environment will be introduced. First, a review of mathematical modeling of cyclone separators is presented. Then, the details of ASSIM and the results of its testing using industrial data from J. K. White Cement Works plant will be discussed. The simulator is mainly based on the Whiten function to model air separators and predicts fine and coarse output streams particle size distributions and flow rates. ASSIM performance was verified and validated by comparing its outputs with measured data collected around an operating air separator. Preliminary software tests indicate the accuracy and precision of the developed code in predicting various properties of output streams as sum of least squares between predicted results and actual data is less than 0.01.

۲Back–calculation of mechanical parameters of shell and balls materials from discrete element method simulations
اطلاعات انتشار: Journal of Mining and Environement، سوم،شماره۱، ۲۰۱۲، سال
تعداد صفحات: ۸
Discrete Element Method (DEM) is extensively used for mathematical modeling and simulating the behavior of discrete discs and discrete spheres in two and three dimensional space, respectively. Prediction of particles flow regime, power draw and kinetic energy for a laboratory or an industrial mill is possible by DEM simulation. In this article, a new approach was used to assess the main parameters of a transparent ball mill constructed in mineral processing laboratory of the University of Tehran. The mill shell and crushing balls are made of Plexiglas® and compressed glass respectively. The true values of mechanical parameters for these materials, required for DEM modeling, were unknown. The authors back–calculated the best values of mechanical properties of Plexiglas and compressed glass materials based on a large number of DEM simulations. Back–calculation procedure was mainly based on the comparison between electrical power draw measured in real mill and mechanical power draw calculated by DEM model while trying to simulate particle flow regime inside the real mill accurately. The results showed that the optimal number and design of lifters can be adequately determined by improving torque and kinetic energy in crushing elements through DEM simulation trials based on the back–calculated mechanical parameters.

۳Multiphase flow and tromp curve simulation of dense medium cyclones using Computational Fluid Dynamics
نویسنده(ها): ، ،
اطلاعات انتشار: Journal of Mining and Environement، چهارم،شماره۱، ۲۰۱۳، سال
تعداد صفحات: ۱۰
Dense Medium Cyclone is a high capacity device that is widely used in coal preparation. It is simple in design but the swirling turbulent flow, the presence of medium and coal with different density and size fraction and the presence of the air–core make the flow pattern in DMCs complex. In this article the flow pattern simulation of DMC is performed with computational fluid dynamics and Fluent software. Simulations are performed to give the axial velocity profile and the air–core. Multiphase simulations (air\water\medium) are performed with RSM model to predict turbulence dispersion, VOF model to achieve interface between air and water phases, Mixture model to give multiphase simulation and DPM model to predict coal particle tracking and partition curve. The numerical results were compared with experimental data and good agreement was observed. Also, separation efficiency of DMC was predicted using CFD simulations and shown by the Tromp curve. The comparison of simulated and measured Tromp curves showed that CFD simulation can predict Tromp curve reasonably within acceptable tolerance, however, for more accurate multiphase simulation including solid phase, it is suggested to use discrete element modeling (DEM) approach coupled with CFD.
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