468242 Large-Scale DEM-CFD Simulation for a Pseudo 2-D Bubbling Fluidized Bed Containing Binary Mixture of Particles with Large Size Difference

Monday, November 14, 2016: 4:40 PM
Golden Gate (Hotel Nikko San Francisco)
Kyohei Higashida, Takuya Tsuji, Kimiaki Washino and Toshitsugu Tanaka, Department of Mechanical Engineering, Osaka University, Suita, Osaka, Japan

In practical applications of fluidized beds, the size of solid paticles is not uniform and large particles coexist with small particles. The large size difference significantly influences the mixing and segregation phenomena in a bed. Despite of its engineering and physical importance, these behaviors are not fully understood. In the present study, large-scale DEM-CFD coupling simulation (Powder Tecnol., 77(1), pp. 79-87, 1993) is performed for a pseudo-2D bubbling fluidized bed containing binary mixture of particles with large size difference. The momentum exchange between the larger particles and fluid is expressed by the fictitious particle method proposed by Tsuji et al. (AIChE J., 60(5), pp. 1606-1620, 2014). The small particles are smaller than the computational cell size used in fluid calculation, whereas the large particles are larger than the cell size.

A snapshot of the simulation results is shown in Fig. 1 where twenty-five million small particles with a diameter of 1 mm and density of 2500 kg/m3 are mixed with five hundred large particles which are 20 mm in diameter and 1600 kg/m3 in density. In addition to the high concentration of the large particles near the side walls (Fig. 1a), falling motion of the large particles inside the bubbles can be observed. The large particles in the bubbles draw the surrounding small particles and induce characteristic structure formations inside the bubbles (Fig. 1b).

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See more of this Session: Fundamentals of Fluidization III
See more of this Group/Topical: Particle Technology Forum