Three-dimensional CFD-DEM investigation of dynamic characteristics of biomass particles in a conical spouted bed

Abstract

A numerical investigation of the three-dimensional conical spouted bed was conducted using CFD coupled with discrete element method to systematically analyze particle-gas flow patterns, bubble volume fluctuations, and fountain characteristics. Moreover, the impact of conical angles on dynamic characteristics is demonstrated under varying gas inlet velocity and particle diameter. Firstly, the simulation result shows that increasing the conical angle is advantageous for enhancing both y-direction and angular velocities of particles, while the impact of this angle varies with inlet velocity and particle diameter. The great inlet velocity and particle diameter significantly enhance the voidage, while the larger conical angle promotes the uniform radial particle distribution. Besides, smaller conical angle and medium inlet velocity is prone to result in the higher frequency and amplitude for the fluctuations of particle height. Meanwhile, enlarging the conical angle results in a shift of the fountain frequency from high to low when the particle size is small. The conical angle plays a crucial role in determining bubble behavior under the condition of medium velocity and small diameter. Besides, the fine particle and small conical angle are prone to cause the noticeable main frequencies.