SIMULATION AND EXPERIMENTAL STUDY ON THE STABILITY OF AIRFLOW DISTRIBUTION ABOVE THE SCREEN IN AN AIR-SCREEN MILLET CLEANING DEVICE

To investigate the influence of airflow distribution stability above the screen surface on the cleaning performance of an air-sieve millet cleaning device, this study employed the lattice Boltzmann method (LBM) to construct simulation models of screen surface flow fields with different screen types. The effects of airflow angle and airflow velocity on the distribution characteristics of airflow near and above the screen apertures were analyzed. The results showed that the flat square-hole screen exhibited high flow-field stability under various airflow conditions, whereas the perforated and fisheye screens were more susceptible to turbulent interference and had poorer uniformity. A simulation validation experiment was carried out using a self-developed airflow velocity and volume monitoring system, and the simulated and measured results showed high consistency in both variation trends and magnitudes, confirming the model’s accuracy. Further bench-scale comparison tests indicated that the flat square-hole screen achieved the best cleaning performance, particularly when using the screen aperture combination of 10 mm (upper screen) and 8 mm (lower screen), resulting in the lowest loss rate and impurity rate. The findings of this study provide a theoretical basis and experimental reference for optimizing screen surface structures and improving the cleaning quality of millet cleaning devices.