A Numerical Study on the Effects of Inlet Velocity Variation on Gas-particle Flow in a Cyclone Separator

This study investigated the influence of inlet velocity on the internal flow characteristics and particle separation performance of a cyclone separator. Computational Fluid Dynamics (CFD) coupled with the Discrete Phase Model (DPM) was used to predict particle trajectories and separation efficiencies under different velocity conditions. The results show that increasing the inlet velocity intensifies the swirling flow and strengthens the centrifugal force within the cyclone. As a result, the axial velocity distribution becomes more pronounced, with stronger downward flow near the wall and intensified upward reverse flow at the center. In the bottom outlet region (Z = 4.5D), clear flow asymmetry associated with the Precessing Vortex Core (PVC) effect is observed, and this phenomenon becomes more pronounced as the inlet velocity increases. Particle trajectory analysis indicates that higher velocities shorten particle residence time and promote rapid migration toward the wall, forming compact helical paths and improving separation efficiency. Analysis using an inverse weighted-sum performance index indicates that an inlet velocity of 15 m/s provides the most favorable balance among the evaluated performance parameters and represents the optimal operating condition for cyclone separator performance.