Hydrodynamic Behavior of a Gas–Liquid–Solid Microfluidized Bed with a Fractal Tree Structure

A fractal tree-structured gas–liquid–solid microfluidized bed was developed to overcome the limited throughput of single-tube microfluidized beds and the hydrodynamic changes caused by direct scale-up. The minimum liquid fluidization velocity, cross-level particle migration, and bubble dynamics at different hierarchical levels were systematically investigated. The results show that the minimum liquid fluidization velocity can be identified by combining the empty-bed-corrected pressure drop-liquid velocity curve with the Hurst exponent. With gas introduction, both the minimum liquid fluidization velocity and the critical liquid velocity for particle migration decrease as the superficial gas velocity increases. The mean bubble diameter decreases with increasing liquid velocity but increases with increasing gas velocity and particle diameter. These results indicate that the fractal tree structure provides a potential pathway for hierarchical scale-up of gas–liquid–solid microfluidized beds.