Effect of particle–particle interaction on the bed pressure drop and bubble flow by computational particle-fluid dynamics simulation of bubbling fluidized beds with shroud nozzle

• A bubbling fluidized bed with two shroud nozzles was simulated in Barracuda®.
• The bed pressure drop and bubble flow characteristics were dependent on the particle stress model.
• The particle normal stress parameter was optimized for the bubbling fluidized beds.

Computational particle-fluid dynamics (CPFD) simulations were carried out to determine the bed pressure drop and bubble behavior in bubbling fluidized beds produced using a shroud nozzle distributor. The fluidized bed had an internal diameter of 0.3 m and height of 2.4 m and was modeled using Barracuda, commercial CPFD software. The bed materials consisted of metal-grade silicon particles with dp, ρp, and Umf of 150 μm, 2330 kg/m3, and 0.02 m/s, respectively. The total bed inventory and the static bed height were 75 kg and 0.8 m, respectively. Air was used as the fluidizing gas at room temperature and atmospheric pressure and was uniformly supplied at the inlet boundary below the distributor. The superficial gas velocity was controlled in the range between 0.07 and 0.17 m/s, and the restitution coefficient of the collision model and the particle normal stress parameter, which affected the particle–particle interaction, were adjusted to obtain accurate simulation data. The results of each simulation were validated by comparing the pressure drop profile to that obtained through experiments under the same conditions. The values predicted for the bed pressure drop and the bubble volume fraction changed according to the restitution coefficient in the collision model and the particle normal stress. At Ps = 5, the bed pressure drop and the bubble flow characteristics were similar to those obtained from the experimental data.

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