Particle-scale modeling study of coaxial jets of gas-solid swirling flow in an industrial-scale annular pipe via CFD-DEM

In this work, the gas-solid swirling flow characteristics of coaxial jets in an industrial-scale annular pipe with a helical swirler is numerically simulated via the CFD-DEM. After validating the numerical model, the general flow pattern of coaxial jets, and gas-particle mixing behavior together with the particle-scale information are discussed. The effect of the geometry parameters of the swirler is studied and analyzed in terms of particle azimuthal velocity and particle Reynolds number. The results demonstrate that the presence of the swirler enhances both the turbulent disturbance and gas vorticity. Increasing vane angle and diameter of swirler is beneficial for the particle dispersion. The particle velocity slightly reduces with decreasing the height in the region 0.6 m < H < 0.7 m but dramatically increases with decreasing the height in the region of height H < 0.6 m. The entrainment of particles by the swirling flow increases the distribution width and azimuthal velocity of particles with decreasing the height.