Structured Bubbling Flow in Granular Matter with Oscillated Gas Injection Which Alternates with Horizontal Position

Gas bubbling in fluidized granular beds has a strong influence on particle mixing and heat transport. Gas bubble dynamics are often mathematically chaotic and vary significantly with system size, complicating scale-up, control and optimization of fluidized bed reactors. Oscillating gas flow or vibrating fluidized beds can lead to the formation of structured bubbling patterns which do not change with increasing system width or height, potentially addressing issues with chaotic bubbling. However, studies have shown that the triangular lattice array of rising structured bubbles forces mixing to be compartmentalized. Here, we model structured bubbling in fluidized beds using two-fluid modeling with gas flow oscillated with different oscillation phases for different regions of the gas distributor. Varying the phase in different sections of the distributor achieves different lattice structures for arrays of structured bubbles, and these different patterns lead to different mixing rates for particles. The effects of gas phase offset and number of slices in the distributor are investigated. We discuss the mechanisms for pattern formation and the implications on having a wider range of bubble patterns achievable in structured bubbling fluidized beds.