## 4 Results and Discussion  
### Influence of Different Loads on Blade Stress and Strain  
During the operation of compressor blades, they are subjected to various load factors. To gain a clearer understanding of how different loads affect the deformation and stress of the blades, this paper analyzed the blade under the following load conditions: aerodynamic load, centrifugal load, and a combination of aerodynamic and centrifugal load. Figure 10, Figures 11 and 12 depict the blade's total deformation and equivalent stress contour maps under various loads. From Figure 10, it can be observed that the maximum equivalent stress on the blade under aerodynamic loading was relatively low. The maximum deformation occurred at the lead edge tip due to the generation of strong shock waves at the leading edge during high-speed rotation. The lead edge dimension was designed to be thinner to reduce shock wave resistance at the leading edge, resulting in reduced stiffness at the leading edge and significant deformation during rotation. Figure 10: Deformation and equivalent stress of blades under aerodynamic load. Figure 9: Comparison of calculated and experimental compressor characteristics. Figure 11 reveals that the maximum equivalent stress under centrifugal loading alone was 277.41 MPa, whereas, under aerodynamic loading alone, the maximum equivalent stress on the blade was 54.31 MPa, representing only 19.57% of the stress exerted under centrifugal loading alone. This indicates that centrifugal load predominantly influenced blade stress. Figures 11 and 12 show that the variation trend of equivalent stress remained consistent when the blade was subjected to centrifugal loading alone or in combination with aerodynamic loading, spreading radially along the blade height direction and concentrating mainly within the upper 33% of the blade length. This is attributed to pressure differences between the suction and pressure surfaces of the blade during high-speed rotation, causing bending of the blade, with the root end face experiencing higher stress as a fixed end, making it prone to fracture and stress fatigue. The three scenarios show that the stress distribution on the blade did not simply follow a linear superposition of forces. A comparison of Figures 10-12 shows that the deformation of the leading edge under aerodynamic loading alone or centrifugal loading alone was less than that under the combined action of aerodynamic and centrifugal loading. Conversely, the deformation of the trailing edge under centrifugal loading alone was greater than that under the combined action of aerodynamic and centrifugal loading. This is because at the blade's leading edge, the forces from aerodynamic and centrifugal loading acted in the same direction, leading to increased deformation. Conversely, at the trailing edge of the blade, the troops from aerodynamic and centrifugal loading acted in opposite directions, partially canceling each other out and resulting in reduced deformation of the blade. In summary, the fluid-structure coupling of the blade represents the optimal approach for studying the stress and strain of impeller blades, providing the most accurate representation of their distribution. It reflects the actual stress and strain distribution of the blades. For compressor blades to operate safely, they must adhere to strength safety criteria, whereby the maximum stress should not exceed the permissible stress [\(\alpha\)]. Compressor blade working conditions involve high temperatures and pressures, so their strength must  
Figure 11: Deformation and equivalent stress of blades under centrifugal load. Figure 12: Deformation and equivalent stress of blades under centrifugal and aerodynamic loads. meet specified requirements; otherwise, they are susceptible to damage.