Coupled gas–solid flow dynamics and particle capture mechanisms in a sweeping–suction cleaning system

To investigate the coupling mechanisms between operational parameters and particle transport behavior in the sweeping–suction system of a road sweeper, a computational fluid dynamics–discrete element method (CFD–DEM)-coupled numerical model was developed based on a specific sweeper configuration. The model captures the dynamic response of particles under the combined effects of disk-brush-induced turbulence and suction nozzle negative pressure. Parametric studies were conducted to evaluate the influence of brush angle, rotational speed, and suction pressure on the cleaning efficiency and migration trajectories of particles with varying sizes. The simulation results indicate that optimal cleaning performance is achieved when the brush angle is within the β3–β5 range, the rotational speed is between 130–160 rev min−1, and the suction pressure is maintained between −2.6 and −2.8 kPa. Flow field analysis reveals a gradual spatial coupling between the rotational airflow induced by the brush and the suction field, forming a stable high-speed adsorption zone. Smaller particles are more susceptible to deviations from the ideal collection path due to the influence of flow non-uniformity. The proposed CFD–DEM framework demonstrates high accuracy and applicability in resolving gas–solid interactions and particle motion in sweeping operations, offering theoretical guidance for parameter optimization and structural design of road cleaning systems.