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Prediction of equilibrium mixing state in binary particle spouted beds: Effects of solids density and diameter differences, gas velocity, and bed aspect ratio
, Article Advanced Powder Technology ; Volume 26, Issue 5 , 2015 , Pages 1371-1382 ; 09218831 (ISSN) ; Dehkordi, A. M ; Sharif University of Technology
Elsevier
2015
Abstract
The state of solids mixing can be considered as a key factor in accomplishment of high efficiency and a uniform product in gas-solid fluidized-beds operating with several different particle sizes. In the present work, coupled DEM-CFD approach was used to carefully investigate the mixing process of binary particles in flat-bottom spouted beds. In this regard, simultaneous effects of particle specifications, operating conditions, and bed dimensions on the equilibrium mixing state of solid mixture were evaluated in detail. Moreover, taking into account the contribution of various parameters, the obtained simulation results were used to draw a correlation for predicting the equilibrium mixing...
Drying in Spouted Beds with Draft Tube
, M.Sc. Thesis Sharif University of Technology ; Molaei Dehkordi, Asghar (Supervisor)
Abstract
Simulation runs have been conducted to predict the evolution of sand drying in conical spouted beds with a non-porous draft tube. In the simulation runs, the moisture content of the solid phase was assumed to be 7 % (kg water/kg sand). The simulation results were validated against experimental results reported by Olazar et al. and good agreement was obtained.Influences of various physical and geometrical parameters such as superficial gas velocity, inlet temperature, length and diameter of draft tube and initial moisture content on the sand drying were investigated. Temperature and gas velocity are the most important parameters for improving the drying process and reduce the drying time of...
Investigation of Hydrodynamics of Spouted Beds with Draft Tube Using DPM Approach
, M.Sc. Thesis Sharif University of Technology ; Molaie Dehkordi, Asghar (Supervisor)
Abstract
In this study the spouted bed with draft tube was investigated by discrete phase model for particulate phase and was tried to simulate the spouted bed with high precision by using of experimental data. So, the most accuracy combination of different parameters and sub models was specified. According to this study, the dispersed k-ԑ turbulence model and standard wall function make best prediction. Gidaspow drag model was used for prediction interaction between phases. This study include the effect of Saffman lift force and Rubinow-keller model was chosen for coefficient of Magnus lift force. In Addition, the solid movement pattern was studied in different area of bed especially in fountain...
Investigation on the Hydrodynamic Behavior of Spouted beds with Draft Tube
, M.Sc. Thesis Sharif University of Technology ; Molaei Dehkordi, Asghar (Supervisor)
Abstract
Spouted beds are widely used in various process industries as an appropriate gas-solid contacting device. Thus, it is of great importance to study their hydrodynamics as a way of improving their design and efficiency. Furthermore, adding a draft tube to spouted beds considerably changes their hydrodynamic behavior. In this research work, the influences of different parameters involved in the simulation of spouted beds were examined to choose the appropriate ones that can reproduce the experimental data reported in the literature. In this regard, Wen and Yu drag model, Lun et al. radial distribution function, a restitution coefficient of 0.95, and a specularity coefficient of 0.02 were chosen...