Impact of draft plate on the inter-chamber interaction in a two-chamber spout-fluid bed

Abstract

The widespread application of the spout-fluid bed in the processing of thermoplastic composites, coal gasification, municipal solid waste gasification, and biomass gasification necessitates a deeply understanding on the flow mechanism of dense two-phase flow in the system in order to improve its design optimization and operation. By tracking the gas and solid phases respectively in the Eulerian and Lagrangian framework, the dense gas-solid flow in the two-chamber spout-fluid bed with and without draft plate was carried out using the computational fluid dynamics coupled with discrete element method (CFD-DEM) to evaluate the impact of the presence of draft plates and the plate length on inter-chamber interaction. The results demonstrate that the interaction of rising bubbles with the spouting channel gives rise to the unfavorable dancing spout phenomenon, which can be alleviated by draft plates. Insertion of the plates lowers the pressure drop magnitudes of both the spouting and background inlets, and the correlation coefficient of the two signals. Furthermore, the draft plates enhance the turbulent intensity of the solid phase in the fountain region and the vertical dispersion in the spout region. Increasing the draft plate length has a significant influence on gas-solid hydrodynamics and chamber interaction.