# Toward the Utilization of 3D Blading in the Cantilevered Stator from Highly Loaded Compressors
## 3 Effects of 3D Blading on the Cantilevered Stator
### Effects of the Blade Sweep
#### 3.1.2 Effects of the Sweep Angle  
To investigate the influence of the sweep angle, the design schemes A2B1, A2B2, and A2B3 are compared in this section, as illustrated in Figure 9. A tip region of each case employs the forward sweep at the 70% span with the same sweep angle as the hub. The orthogonal/straight blade works as the benchmark of comparison. Figure 8: The comparison of the streamwise leakage mass flow rate under different sweep heights (\(\varphi=0.46\)). Figure 7: Radial distribution of aerodynamic performance for the cases with different sweep heights. (a) \(\varphi=0.52\); (b) \(\varphi=0.46\). Figure 10 presents the pressure rise and loss characteristics of the cantilevered stators. It can be seen that the aerodynamic performances of different design schemes share similar trends; except for the near-stall condition, the pressure rise coefficients are enhanced significantly in comparison with the orthogonal blade. Observation of the near-stall condition indicates that the sweep angle should be controlled within a proper range, as a too-large sweep angle (A2B3, 150 deg) will deteriorate the blade pressure rise coefficient; however, the performance remains better than that of the straight blade. The flow field distributions for the design schemes with different sweep angles are given in Figure 11. Similar to the previous conclusions, the forward sweep will weaken the flow separation in the blade corner region, but at the same time enhance the flow separation at the midspan. With the increase of the sweep angle, the leakage flow tends to move toward the pressure surface of the adjacent blade, thus increasing the traveling distance to the outlet. Consequently, the mixing of the leakage flow with the corner flow is improved, and the radial dimension of the low-speed area at the blade outlet shrinks. It should be noted that excessively large sweep angle will lead to a significant increase in the suction surface flow separation (A2B3), thereby weakening the aerodynamic performance gains brought by the forward sweep; thus, the sweep angle should be appropriately selected when at the design stage. Figure 10: Pressure rise and loss characteristics for the stator with different sweep angles. (**a**) Pressure rise and (**b**) loss. Figure 9: Radial distribution of blade sweep for the cases with different sweep angles. The radial distribution of the aerodynamic parameter for the cases with different sweep angles is given in Figure 12. Results of both the \(\varphi\) = 0.52 and the \(\varphi\) = 0.46 conditions are provided. With the increase of sweep angle, the flow coefficient at the hub region increases, resulting in the improvement of the flow capacity. On the contrary, the flow capacity at the upper span parts is decreased, corresponding to the widening of the blade wake in Figure 11. The influence of the sweep angle on the radial flow of the blade is more significant at small mass flow rates. Considering the influence of the sweep angle on the corner flow and the blade separation flow, a moderate sweep angle (approximately 135\({}^{\circ}\) for the present study) is appropriate for the cantilevered stator. Figure 13 presents the variation of the mass flow rate for the stator leakage flow along the streamwise direction. Increasing the sweep angle tends to reduce the leakage flow at the blade leading edge, yet it will enhance the leakage flow in the other regions. The total mass flow rate of the leakage flow will be increased upon the utilization of the forward sweep, thus strengthening the interaction of different corner flow structures. Figure 11: Flow field distribution for the cases with different sweep angles. Figure 12: Radial distribution of aerodynamic performance for the cases with different sweep angles. (**a**) \(\varphi\) = 0.52; (**b**) \(\varphi\) = 0.46. Hence, the forward sweep could inhibit the transverse flow near the hub endwall and alleviate the flow separation at the corner region.