Effect of combining swirling devices on drying of wet particles in spouted beds: Experiment and simulation

Abstract

Through comparing the drying characteristics of the conventional spouted bed (CSB), the spouted bed with a swirling blade (ASB), and the spouted bed with a combination of a swirling blade and a swirling nozzle (ASNSB), the influence of swirling devices on the drying effect was investigated. In the experiments, various operating parameters were changed to comprehensively discuss the differences in drying rate among these spouted beds. Based on the experiments, the drying process of ASNSB was simulated by CFD. The gas-solid two-phase flow and mass transfer during the drying process were systematically analyzed. The experimental results demonstrate that, compared with CSB, the introduction of swirling devices in ASB and ASNSB effectively promotes the flow of particles and increases the drying rate, especially when the filler mass is low and the particle size is large. Furthermore, the drying promotion effect of the ASNSB is more pronounced at low temperatures and high gas flow rates. The simulation results show that in the drying process of ASNSB, mass transfer mainly occurs on both sides of the conical region, and the axial swirling blade changes the direction of gas flow and promotes the mixing of particles.