## 4 Simulation Study of De-Bonding Performance of Composite In Situ Separator
### Results and Discussion
Among the five simulation results, the separator with a pitch of 40 mm exhibited the highest second peak value of the particle cementing bond stress, exceeding the required 21.5 kPa for de-bonding, indicating that it likely had the best de-bonding performance. 4. Pressure Gradient  
The pressure gradient is an important factor affecting the load on the cementing bonds. Figure 9 shows the pressure gradient within the flow field of the composite separator for different pitches. As depicted in the figure, the smaller the pitch of the composite  
Figure 8: Relationship between the bond load and axial displacement with different pitches. separator, the greater the pressure gradient difference on the outer side. According to previous studies [17; 18; 19], a smaller pitch in the composite separator results in a higher tangential velocity of the fluid within the cylindrical section, causing the dispersed phase to experience greater centrifugal force and, thus, tending to concentrate more toward the wall surface. Consequently, the pressure gradient also increases. Therefore, in the cylindrical section of the composite separator with a smaller pitch, the pressure gradient force on the cementing bonds of the GHBS particles was also greater. Therefore, it can be concluded that when the pitch of the helical flow channel was 30 mm, the composite separator achieved the best de-bonding performance. 2 Analysis of the Impact of Inlet Type on De-Bonding Performance of Composite Separator  
Recently, there have been numerous studies on the impact of different inlet types on the performances of separators, which have found that inlets such as the involute type can reduce the cut size and improve the separation efficiency. To investigate whether different inlet types would affect or optimize the performance of the composite separator, three types of inlets--circular, involute, and oblique--were selected in addition to the tangential inlet for study. 1. Axial Displacement  
Figure 10 shows the relationship between the axial displacement and time for GHBS particles in composite separators with different inlet types. As shown in the figure, the residence times of particles in the cylindrical section of composite separators with the four types of inlets, tangential, circular, involute, and oblique, were 0.51, 0.43, 0.33, and 0.33 s, respectively. The total residence times of particles in the composite separators with involute and oblique inlets were also shorter. Shorter residence times favor an improved working performance and throughput of the separator, but are detrimental to the de-bonding performance. 2. Particle Trajectory  
Figure 11 shows the movement trajectories of GHBS particles within the composite separators with different inlet types. As shown in the figure, the main impact of different inlet types on the particle trajectories was reflected in the accelerated convergence of the particle trajectories with the flow channel. GHBS particles passing through the involute and oblique inlets had movement forms and directions that better matched the helical flow channel, leading to quicker completion of the flow in the cylindrical section and shorter  
Figure 9: Pressure gradient with different pitches. 1 The tangential inlet composite separator showed the best performance among the four separators, with the highest average load value reaching about 25 kPa. It also maintained a high-stress level throughout the cylindrical section, indicating a good debonding effectiveness. 2 The circular inlet composite separator achieved the highest cementing bond stress value of 25.7 kPa. However, high-stress values were only observed in the inlet section, with stress levels in the rest of the cylindrical section being much lower than those in other types of composite separators. 3 In the involute inlet composite separator, the cementing bond stress of the particles reached its maximum value at the inlet and then gradually decreased with increasing axial distance.