![]() (13) Their results (11) demonstrated that the formed agglomerates can be broken on the bubble’s cap. This finding was also reported by Wu et al. Their CFD–DEM results revealed that highly cohesive particles tend to form large agglomerates in dense regions. They reported that DEM simulations fail to capture agglomerates raining down from the bubbles’ cap without accounting for the cohesive forces. (11) used the CFD–DEM approach to evaluate the formation of particle agglomerate in a fluidized bed of Geldart A particles. In this approach, the Navier–Stokes equation is solved for fluid motion, while the motion of individual particles is simulated by solving the second Newton’s law of motion. Such fluidization charts can facilitate the design of fluidized beds by predicting the conditions under which the formation of particle agglomeration and clustering is likely in fluidized beds.Ī group of researchers employed coupled computational fluid dynamics (CFD) and −discrete element method (DEM) simulations to predict fluid (i.e., gas) flow and particle flow, respectively. The obtained regime map can be extended to incorporate the effect of dimensionless velocity and dimensionless diameter as a comprehensive fluidization chart for cohesive particles. Comprehensive analysis of the shear-to-yield ratio reveals that the observed regime map is attributed to the competition between the shear stress and yield stress acting on the particles. Our simulation results reveal the formation of four different regimes of fluidization for cohesive particles: (i) bubbling, (ii) bubbling–clustering, (iii) bubble-less fluidization, and (iv) stagnant bed. To evaluate fluidization regimes, a set of simulations was conducted for a wide range of particle cohesivity (e.g., Bond number and tensile pressure prefactor) at two different fluidization numbers of 2 and 5. The formation of such granules and clusters highly depended on the particle Bond number and the tensile pressure prefactor. ![]() The results of our simulations demonstrated that the modified TFM approach can successfully predict the formation of particle agglomerates and clusters in the fluidized bed, induced by the negative (tensile-dominant) pressure. Specifically, the kinetic theory of granular flow (KTGF) was modified based on the solid rheology developed by Gu et al. ![]() To do so, a two-fluid model (TFM) platform was developed to account for the cohesivity of particles. The fluidization behavior of cohesive particles was investigated using an Euler–Euler approach. ![]()
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