In this article, the intensifi cation of solids mixing in tapered fl uidized beds equipped with an inlet jet and varying apex angles

(2.86°, 5.71°, and 8.53°) has been investigated. In this regard, a particle segregation number (PSN) and multi-fl uid modeling

(MFM) approach were employed to analyze the mixing process. The study utilized solid mixtures composed of particles

with a density of 2500 kg/m 3 and diameters of 240 and 510 μm. Simulation results were validated against our experimental

data obtained using a small tapered bed without an inlet jet and those obtained using a larger tapered bed with an inlet jet,

as Huilin et al. (2003) reported. This validation demonstrates satisfactory agreement between the simulation results and

experimental data. The solids mixing process in a columnar fl uidized bed was found to resemble that in a tapered bed with an

apex angle of 2.86°. Increasing the apex angle leads to a larger equilibrium mixing value. In addition, the infl uences of inlet

jet velocity and nozzle diameter on the solids mixing process were investigated. The simulation results indicated that higher

inlet jet velocities and larger nozzle diameters enhance the equilibrium mixing index value. Notably, inlet jet velocities of

0.7 and 0.8 m/s exhibited three distinct solids mixing stages: rapid, slow, and equilibrium, whereas higher jet velocities only

involved rapid and equilibrium mixing stages. Moreover, this study further examined how the initial arrangement of solid

particles aff ects the mixing index, providing valuable insights into optimizing the solids mixing process. Furthermore, the

present work sheds light on the factors infl uencing the mixing of solids in tapered fl uidized beds, off ering valuable insights

for further research and industrial applications.