## 3 Results and Discussion
### Optimization Design of the Bag Filter
#### 3.2.3 Comparative Analysis of Full-Scale Optimization Models  
To obtain a more accurate representation of the internal flow field distribution and particle movement, as well as to more precisely compare the optimization effects of different schemes, CFD simulations were conducted on the full-scale model of each optimization scheme under typical operating conditions. The continuous phase velocity contours are shown in Figure 11, while the particle trajectory plots are presented in Figure 12.  
Figure 11: Velocity contours of continuous phase for the optimization models in full scale. By comparing the continuous phase velocity contours of the R\({}_{5}\) cross-section of each model in Figure 11, it is evident that the dust-laden air enters the hopper from the inlet channel and impacts the descending deflectors. After the collision, part of the airflow rises along the deflector into the filter chamber, while another portion continues forward, and eventually strikes the hopper wall. Some of the airflow then moves upward along the wall, while the remainder flows downward, forming a vortex at the bottom of the  
Figure 12: Particle trajectory plots for the optimization models. (**a**) Particle diameter = 2.5 \(\upmu\)m; (**b**) particle diameter = 5.0 \(\upmu\)m.  
hopper. Vortices are also observed between the deflectors and between the deflectors and the hopper walls. A closer examination of the velocity contours of the R\({}_{5}\) cross-section reveals that after the high-velocity dust-laden air enters the hopper via the inlet channel, the 804 mm long descending deflector (the first deflector in Scheme 2) has minimal impact on the continuous phase flow. Similarly, the 1054 mm long deflector (the first deflector in Schemes 1, 4, and 5 and the second deflector in Scheme 2) shows limited guiding effect. However, after the dust-laden air collides with the 1304 mm long descending deflector, there is a noticeable shift in the flow direction. In Schemes 1, 3, 4, and 5, it is observed that, under the guidance of the 1304 mm deflector, the subsequent descending deflectors (1554 mm and 1804 mm) have little impact on guiding the continuous phase flow. The impact of the high-velocity inlet flow on the hopper walls is significantly reduced in Schemes 3 and 4, which is consistent with the results from the flow field simulations of the scaled-down simplified models. The differing effects of deflectors with varying lengths on the inlet airflow can be explained as follows: If the dust-laden air entering the hopper is viewed as a cylindrical jet, the bottom edge of the 1054 mm long deflector is tangent to the surface of the cylindrical jet. As a result, the dust-laden air does not directly collide with the 804 mm long deflector after entering the hopper. Instead, only a small portion of the jet is influenced by the edge of the 1054 mm long deflector, altering its flow direction. The 1304 mm long deflector divides the jet into two parts: one rises along the deflector, while the other is directed downward at an inclined angle. Due to the inclined airflow, only a small portion of air along the edges collides with the 1554 mm and 1804 mm long deflectors, while the majority of the airflow moves directly toward the hopper wall. Velocity contour analysis of the R\({}_{1}\) cross-section from the different models shows that in Schemes 1, 2, and 5, the airflow velocity near the bottom of the filter bags is higher near the outer walls. In contrast, in Scheme 3, the airflow velocity near the inlet is higher at the bottom of the filter bags. This indicates that the four deflector designs do not adequately address the channeling phenomenon within the bag filter. By comparison, Scheme 4 demonstrates better consistency in the airflow velocity near the surfaces of the filter bags on both the inner and outer sides, allowing for a more uniform distribution of airflow across the filter bag area. This configuration helps to alleviate the channeling phenomenon more effectively.