## 4 Simulation Study of De-Bonding Performance of Composite In Situ Separator
### Results and Discussion
Since its maximum value only reached about 19 kPa, the involute inlet composite separator could not effectively achieve de-bonding. 4 The stress values in the oblique inlet composite separator differed from those in the other three separators. Instead of reaching the maximum value immediately after entering the separator, the stress peaked at an axial displacement of about 35 mm before gradually decreasing, with a subsequent rise near the exit of the flow channel. This phenomenon occurred because the angle of the inlet was close to that of the flow channel. As a result, the fluid and particles did not immediately attain high angular velocities upon entering the separator, but gradually reached the maximum value after a certain axial displacement. 4 Pressure Gradient  
Figure 13 shows the pressure gradient distributions within the composite separators with four different inlet types. As depicted, the influence of the inlet type on the pressure gradient within the separator was primarily noticeable at the inlet section, and the extent of this influence was not significant. Figure 12: Relationship between the bond load and axial displacement for different inlet types. 3. Analysis of De-Bonding Performance of Composite Separator for Particles with Different Sizes  
1. Axial Displacement  
Figure 14 shows the relationship between the axial displacement and time for GHBS particles with different sizes within the composite separator. As shown, except for particles with diameters of 10 \(\upmu\)m, particles with various sizes had similar residence times in both the cylindrical section and the overall separator, approximately 0.4 and 1.6 s, respectively. This phenomenon significantly differed from the movement patterns of GHBS particles in a classic hydrocyclone separator. The reason for this discrepancy was that in a classic separator, larger particles, driven by their greater mass, have higher axial speeds and accelerations within the cylindrical section and encounter greater axial resistance in the conical section. In the designed composite separator, the helical flow channel caused particles with different sizes to have similar axial speeds, and the speed losses when entering the conical section were also similar, resulting in comparable residence times within the separator. In addition, it can be observed that 10 \(\upmu\)m particles, after moving to the middle position of the separator conical section, ceased to exhibit further axial movement and remained in the conical section. This phenomenon did not occur in the classic separator. The reason was that small-sized GHBS particles, lacking sufficient axial speed in the cylindrical section, could not overcome the resistance of the conical surface to reach the underflow outlet upon entering the conical section, leading to accumulation in the middle of the conical section. It is foreseeable that when a large number of particles accumulated in the conical section of the separator, some particles would be pushed toward the underflow outlet by the particles behind them, while others would be pushed radially, eventually crossing the zero-velocity envelope and being discharged from the overflow outlet. Therefore, it can be concluded that the composite separator reduced the separation efficiency of GHBS particles with diameters less than 10 \(\upmu\)m, thereby reducing the separator's operational performance. Figure 13: Pressure gradient distribution for different inlet types. Particle Trajectory  
Figure 15 shows the trajectories of GHBS particles with different sizes within the composite separator. Particles with diameters of 10 \(\upmu\)m did not leave the separator through the underflow outlet within 3 s, but instead accumulated in the middle of the conical section. The results indicate that when the particle diameter was not less than 20 \(\upmu\)m, there was no significant difference in the particle trajectories, only differences in the angular velocity values.