Structured bubbling flow in fluidized beds with oscillating gas injection which alternates with horizontal position

AIChE Journal · 2025-03-14

Abstract Structured bubbling with a triangular lattice pattern has been demonstrated previously to form in fluidized beds with oscillated gas injection velocity. Here, we demonstrate using two‐fluid model simulations that dividing the gas distributor into slices and oscillating gas flow with a phase offset between consecutive slices enables structured bubbling to form with a wider range of bubble sizes and lattice configurations. Local particle solidification below bubbles leads to the formation of these structures, as manifested in high particle pressures in simulations. Varying the number of slices and phase offset enables a number of configurations that mix particles faster than cases with conventional structured bubbling or unstructured bubbling with the same overall gas flow rate.

Controlling activated aluminum hydrolysis via water injection rate

International Journal of Hydrogen Energy · 2025-10-23 · 1 citations

Effect of horizontal vibration on structured bubbling in gas-fluidized beds: CFD-DEM simulations

Chemical Engineering Science · 2025-12-04

Bubbling and mixing of vibrated and non-vibrated gas-fluidized active granular matter

Soft Matter · 2025-01-01

Numerical simulations are used to study the effect of varying magnitudes of active matter force on non-vibrated and vertically vibrated gas-fluidized granular materials. We observe that if the ratio of active matter force to gravity is less than 1, but above 0, gas bubbles produced by fluidization generally increase in size which promotes mixing. However, if the ratio of active matter force to gravity exceeds 1, then the active matter force suppresses bubbling and the mixing is poorer. Furthermore, we find that if the active matter force significantly exceeds 1, the mixing can be enhanced despite no bubbling, owing to diffusion. By vertically vibrating the granular bed, and subsequently producing structured bubbling, we find that bubbles persist for larger active matter force, which we attribute to the larger bubble size observed for structured bubbling as compared to chaotic bubbling. Finally, we present a non-dimensional regime map describing the transition of sub-diffusive, diffusive, and advective transport regimes depending on the balance of active matter force to drag force to gravitational force for fluidized active granular materials.

Effects of distributions of particle size and density on structured bubbling in fluidized beds: CFD-DEM simulations

Chemical Engineering Science · 2025-04-25 · 3 citations

Author response for "Bubbling and Mixing of Vibrated and Non-Vibrated Gas-Fluidized Active Granular Matter"

2025-04-02

Anomalous descent of intruders in vibrated gas-fluidized granular materials

Physical review. E · 2025-01-24 · 1 citations

The descent of dense intruder disks through granular material fluidized by vertical gas flow and vibration is investigated experimentally and computationally. Single intruders descend with a velocity which oscillates based on distance above the bottom of the system, which simulations show is due to a spatially dependent void fraction in the granular material changing the effective drag force on the intruder. Two vertically aligned intruders undergo a drafting-kissing-tumbling analog which forms because the bottom intruder decelerates due to particle compaction from the weight of the top intruder.

Mitigation of Spouted Bed Instabilities Using Vibration: Experiments and CFD-DEM

Industrial & Engineering Chemistry Research · 2025-01-13 · 2 citations

Spouted bed instabilities, such as spout deflection and spout oscillation, are well understood to decrease the particle recirculation rate, which decreases drying and mixing efficiency. A recent study (Punch et al., Chem. Eng. J., 2024 495, 153459) showed that vertical vibration could be used to decrease spout instabilities in dry and wet spouted beds at low bed height for large particles, without compromising recirculation rate. Here, we show experimentally that vertical vibration can also be used to reduce spout instabilities for spouted beds of dry particles with a large inlet diameter to particle diameter ratio (>20), which are traditionally highly unstable, and present a regime map to guide scale-up of industrial vibrated spouted beds. Numerical CFD-DEM simulations are used to elucidate the mechanisms of vertically vibrated spouted beds and reveal that vertical vibration produces a force wave each vibration cycle which propagates vertically through the bed and homogenizes the particle recirculation rate into the spout, mitigating spout instabilities.

Faraday waves in gas-fluidized beds subject to combined vertical and horizontal vibration

Powder Technology · 2024-03-15 · 6 citations

Towards accurate modeling of vibration in CFD-DEM simulations of vibrated gas-fluidized beds without using a moving mesh

Chemical Engineering Science · 2024-06-28 · 5 citations