## 3 Result
### Analysis of EDEM-Fluent Coupled Simulation Results for the Screening Process
#### 3.2.2 Analysis of the Influence of Airflow Velocity on Sieving Performance  
During the screening process, wind speeds of 9 m/s, 10 m/s, 11 m/s, and 12 m/s were employed to simulate the screening performance of raisins and foreign objects under different airflow conditions, as illustrated in Figure 24. By comparing the material distributions in various screening channels under different wind velocities, it was observed that wind speed exerts a significant effect on the screening rate between raisins and foreign objects. Based on the simulation results, when the wind speed was 9 m/s, stones fell into the heavier foreign object screening channel closest to the air outlet. A portion of the heavier  
Figure 23: Z-plane pressure contour plot. Figure 24: Sieving processes corresponding to different airflow velocities. raisins also entered this channel, while the remaining raisins were directed into the middle raisin screening channel. However, due to the low wind speed, some fruit stems, branches, and plastic particles also entered the middle raisin channel, with the remaining light foreign object (fruit stems, branches, and plastics) falling into the lighter foreign object channel near the air outlet. The screening rate was relatively poor at this wind speed. When the wind speed increased to 10 m/s, the separation rate between raisins and foreign object improved, with enhanced removal rates of lighter foreign object and reduced raisin loss rates. Nevertheless, a small portion of light foreign object still entered the middle raisin channel. Further increasing the wind speed to 11 m/s resulted in more pronounced screening performance: most foreign object was effectively separated, and all raisins fell into the guide trough of the middle screening channel, and formed a single-layer structure entering the visual inspection area. However, at 12 m/s wind speed, although foreign object removal rates remained high, a small quantity of stones entered the middle raisin channel, and a few raisins migrated to the outermost lighter foreign object channel, leading to increased raisin loss. Quantitatively, the screening rate of raisins under different wind speeds was analyzed by counting the number of raisin particles in the middle raisin channel versus other channels after simulation completion, as shown in Table 8. Similarly, the screening rate of various foreign objects was evaluated by comparing the particle counts in their respective channels with those in the middle raisin channel, also presented in Table 9. At 11 m/s wind speed, the raisin screening rate reached an optimal 96.46%, with only 3.54% of foreign object entering the raisin channel. A comprehensive analysis revealed that fruit stems and branches, due to their morphological and density characteristics, exhibited a satisfactory separation rate at relatively low wind speeds, albeit with a higher raisin loss rate. As wind velocity increased to 10 m/s, the removal rate of fruit stems and branches improved, while the raisin loss rate decreased concomitantly. For stones, their higher density enabled effective screening even at lower wind speeds; however, excessively high velocities compromised screening performance. The separation rate of plastic fragments depended on both density and shape: lighter fragments were adequately separated at lower velocities, whereas heavier fragments required elevated wind speeds for effective separation. Notably, a minor proportion of foreign objects still entered the intermediate channel due to inter-particle collisions, necessitating a fine removal module for secondary processing.