The Aerodynamic Effects of the Blade Lean on a High-Aspect-Ratio Transonic Axial Flow Rotor

In this study, the effect of tangential blade lean on the aerodynamic characteristics of low-transonic, high-aspect-ratio axial flow compressor rotor has been investigated by using the computational fluid dynamics. The B-Spline curvature with four control points of 25%, 50%, 75% and 100% of span have been used to define the blade stacking line. Various leaned rotors have been created by rotating the circumferential position of control points and they have been simulated by Computational Fluid Dynamics (CFD). At the best state, the leaned blade improves the adiabatic efficiency and total pressure ratio of compressor about 0.55% and 0.75%, respectively. The results show that, lean angle at 100% span has most effect in the peak adiabatic efficiency rather than lean angle at other control points. Also, the results indicate that, in low-transonic, high-aspect-ratio rotor blades, the tangential change of the stacking line only causes the reduction of secondary flow, while the previous studies on high-transonic low-aspect-ratio rotor blades, such as NASA Rotor 37 and NASA Rotor 67 revealed the movement of shock wave toward the downstream and the reduction of the secondary flow.