Effect of liquid bridging on bubbles injected into a fluidized bed: A magnetic resonance imaging study

Rapid magnetic resonance imaging was used to take snapshots of solids volume fraction and particle velocity fields in an incipiently fluidized bed with single bubbles injected under both dry and wet conditions. Under wet conditions, cohesive liquid bridges formed between particles, altering the flow such that bubbles became flatter as compared to dry cases, and in some cases, the bubbles split or disintegrated entirely. The alteration in bubble behavior can be attributed to liquid bridging causing an increased heterogeneity in the roof of the bubble, which decreases the drag force on particles in the roof such that the gas flow through the roof can no longer support the weight of the particles in the roof. Quantification of the change in bubble behavior shows that increasing liquid loading has a much stronger effect on bubble behavior than increasing liquid viscosity, and liquid bridging affects small bubbles more than large bubbles.