## 4 Analysis of CFD Simulation Results
### Analysis of Simulation Results of Blockage Conditions
#### 4.2.2 The Influence of Blockage Pattern on the Distribution of Pipeline Characteristics  
To study the effect of blockage shape on pressure distribution, three common shapes were simulated under identical conditions. The resulting pressure variations for each shape are compared in Figure 12.  
Under a 25% blockage condition, the pressure drop along the pipeline for all three shapes is nearly identical. When the blockage is 50%, the three types of blockages have different changes in the pressure drop along the way. As the blockage degree increases, the pressure drop increases, and the three types of blockages become more and more obvious. As the blockage degree increases, the pressure drop becomes more pronounced.  
greater the roughness of the pipe wall, the larger the frictional resistance, and the more likely the particles are to stop, accelerating the formation of deposition-type blockage. To prevent deposition-type blockage, it is recommended to select pipes with smooth inner walls and low roughness when designing slurry injection pipelines.  
Figure 12: Cont.  
4.2.3. The Influence of Blockage Location on Pipeline Pressure Distribution  
Simulations were conducted to examine the effect of blockage location on pressure distribution, focusing on straight and bent sections under a \(75\%\) blockage condition. The pressure drop along the pipeline was compared for three blockage shapes. Results are presented in Figure 13.  
Figure 12: Pressure variation along the pipeline under different blockage types.  
Figure 13: _Cont._  
Based on the analysis of Figure 13, it can be concluded that the variation in blockage location has minimal impact on the pressure distribution. The pressure drop along the straight section of the pipeline decreases approximately linearly, while in the bent section, the pressure follows an arcuate reduction in accordance with the theoretical model. When the blockage occurs at the bend, the pressure first decreases linearly along the arc at the blockage point and then continues to drop along the original curvature of the bend.  
Figure 13: Variation in pressure along the pipe at different blockage locations.  
Overall, the differences in pressure distribution due to blockage location are insignificant. Whether in straight or bent sections, the pressure-drop variations show little distinction. Therefore, compared to blockage degree and blockage shape, the location of the blockage has a smaller effect on the water flow pressure inside the pipeline.  
According to Table 2, Figures 14 and 15, the data reveal a clear trend: as the degree of blockage increases, the pressure drop (Pa) induced by all three types of blockages (A-blockage, B-blockage, and C-blockage) rises significantly. Notably, B-blockage results in the highest pressure drop across all levels of blockage, while A-blockage causes the lowest pressure drop. At a 25% blockage degree, B-blockage leads to the greatest pressure drop of 464,150 Pa, whereas A-blockage results in the lowest pressure drop of 424,500 Pa, and C-blockage induces a pressure drop of 397,240 Pa. As the blockage degree increases to 50%, the pressure drop for B-blockage rises further to 1,229,830 Pa, significantly exceeding that of A-blockage (932,270 Pa) and C-blockage (1,069,050 Pa). At a 75% blockage degree, B-blockage causes the highest pressure drop, reaching 5,542,770 Pa, compared to 3,652,260 Pa for A-blockage and 4,669,570 Pa for C-blockage. B-blockage generates the greatest flow resistance within the pipeline, leading to the most substantial pressure drop. Therefore, timely removal of B-blockage is essential for maintaining the normal operation of the pipeline. Furthermore, as the degree of blockage increases, the pressure-drop variation becomes more pronounced, indicating a nonlinear impact of the blockage on flow behavior.