Air curtain dust-collecting technology: An experimental study on the performance of a large-scale dust-collecting system

The escape of dust particles from dust-producing sources in welding, wood-, and crop-processing sites is hazardous for human health and can violate strict technological requirements. This study proposed artificial unloading of dust-producing links in tobacco plants and designed an air curtain dust-collecting system with large size of 2m × 2m × 2m. The dust was first isolated by air curtain jets produced by the air curtain generator and then driven away by the suction airflow on the top of the device to achieve the effective dust collection. The flow field characteristics in the dust-collecting system and smoke fine particles' capturing behavior were qualitatively analyzed via a tracer smoke. Moreover, the effects of the air curtain's jet velocity, angle, and the exhaust-to-pressure ratio (EPR) on the system's dust-collecting performance were experimentally evaluated. The airflow's entrainment and smoke exhaust capacity were improved with increased air supply and air suction quantities. At a total air supply and air suction quantities of 3706 and 4322 m3/h, respectively, the tracer smoke exhibited a pronounced columnar collecting state. Excessive and insufficient jet velocities were found inappropriate for the developed large-scale dust-collecting system. The optimal jet velocity range was determined as 12–15 m/s, with a corresponding air supply quantity range of 3110.4–3708 m3/h. Within a reasonable EPR range of 0.9–1.0, the efficient and cost-effective dust-collecting performance was achieved. As the jet angle increased, the system's dust-collecting efficiency dropped steadily, and a zero jet angle was optimal. The optimal parameters determined through the orthogonal experiment were as follows: jet velocity of 15 m/s, EPR of 1.0, and jet angle of 0°. Under the optimal parameter setting, the dust-collecting efficiency reached a maximum of 96.88%. •Air curtain generator with 2m length has favorable uniformity and less diffusion.•4 m3 large-scale air curtain dust-collecting system shows its effectiveness.•Smoke for dust-collecting flow pattern shows the columnar dust-collecting state.•Highest dust-collecting efficiency of the system can reach 96.88%.