Previously, using real-time magnetic resonance imaging (MRI), we found two anomalous bubble collapse phenomena that show the manifestation of an instability when two bubbles interact in a fluidized bed (Phys. Rev. Fluids 4, 034303). It was shown that (1) a bubble collapses when two bubbles are injected side-by-side and (2) a lower, smaller bubble collapses trailing an upper, larger bubble. Later, a CFD-DEM study (Phys. Rev. Fluids 5, 034304) reproduced bubble collapse phenomenon (1) and revealed the detailed mechanisms. Recently, a comprehensive two fluid modeling study matching the MRI experiments was performed. The simulation results show that two fluid modeling can capture the above two bubble collapse phenomena, and can identify the difference in permeability to interstitial gas flow due to different particle diameters, showing that the two aforementioned bubble collapse phenomena only occur in the bed of 3 mm particles but not in a bed of 1 mm particles when the same injection conditions are used. This study was recently published in Chemical Engineering Science. The invited cover will be appeared on the front cover of Chemical Engineering Science in a future volume. Qiang Guo, Azin Padash, and Chris Boyce are the authors of the paper.
