(135a) A Structured Bubbling Phenomenon in Vertically Vibrated Binary Gas–Fluidized Beds

Granular flows are ubiquitous both in natural and industrial processes such as pharmaceuticals production¹, mining and food–processing. A vital hydrodynamic flow regime inside granular fluidized beds is the free–bubbling regime which exhibits enhanced heat transfer characteristics. With the mathematically chaotic motion of these rising bubbles, the system’s characteristics are unpredictable. Recent studies^{2, 3} have shown that this chaos can be suppressed by oscillating the gas flow rate or vertically vibrating the fluidized beds. In particular, vertical vibration at the resonant frequency generates periodic, triangular, structured array of bubbles, across various system dimensions and particle sizes⁴. Extending this phenomenon further to the mixtures, here we demonstrate that this dynamically structured bubble configuration persists in binary mixtures composed of different density ratios, different particle size ratios and across different system sizes. Discrete Element Method (DEM) simulations accurately capture the bubble structuring for various initial particle arrangements and also facilitate the quantification of mixing characteristics. The optically imaged experimental data is compared with simulation predictions.

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