Solids lateral mixing and compartmentalization in dynamically structured gas–solid fluidized beds

Structured bubbling in layered gas‐fluidized beds subject to vibration: A CFD‐DEM study

“…The difference between experiments and simulations shows that CFD‐DEM simulations can only predict the structured bubbling pattern well in cases with only one row of fully developed bubbles present in the bed and show large deviations in predictions of structured bubbling pattern in cases with multiple rows of fully developed bubbles present in the bed. The same deviations of CFD‐DEM simulations have also been noticed in two very recent CFD‐DEM simulation works of structured bubbling with pulsed gas flow 34,35 and were attributed to a narrow computational domain and the associated interaction with front and rear walls 34 . Such factors should also play a role in the current work because the simulated bed depth was reduced from the experimental value of 10 mm 20 to 4 mm to reduce the computing efforts.…”

“…Nevertheless, the comparison shown in Table 4 and the quantitative agreement of the U mf between the CFD‐DEM simulations and experiments indicate that the CFD‐DEM simulations can be used, at least quantitatively and in some ways quantitatively, to validate the proof of concept of the layered configuration to extend the structured bubbling pattern. This is further evidenced by previous works 33–35 that show CFD‐DEM simulations can provide quantitative prediction of the structured bubbling pattern with pulsed gas flow.…”

“…The first is that the structured bubbling pattern with pulsed gas flow likely cannot be maintained in a higher particle height. It is noted that four recent CFD‐DEM simulations of structured bubbling with pulsed gas flow used an initial particle height of 3.8 36 and 4.5 cm, 33–35 similar to the 3 cm particle height used here. Guo et al 20 has attributed the better scaling of structured bubbling with increasing particle height by vibration than by pulsed gas flow to the fact that system vibration can persist more through the particle height, while gas flow oscillation effects are more dissipated higher in the bed due to percolating gas motion through bubbles and interstices between particles.…”

“…The first is that the structured bubbling pattern with pulsed gas flow likely cannot be maintained in a higher particle height. It is noted that four recent CFD-DEM simulations of structured bubbling with pulsed gas flow used an initial particle height of 3.8 36 and 4.5 cm, [33][34][35] similar to the 3 cm particle height used here. Guo et al 20 has attributed the F I G U R E 1 0 Discrete particle distribution during two vibration periods in a fluidized bed with three layers.…”

“…As a result, the overall pattern is far from ordered for the h = 9, 12, and 15 cm cases. bubbling with pulsed gas flow 34,35 and were attributed to a narrow computational domain and the associated interaction with front and rear walls. 34 In Figure 3, the corresponding correlation coefficient of free bubbling cases in a fluidized bed without vibration is also provided for comparison.…”