Aeroelastic tailoring for rotor blades of transonic swept fans

For further raising fan stage's Pressure ratio, there are two main restricting factors. First, increasing rotor's tip wheel speed will strengthen the shock waves in rotor, and it is possible to decrease the stage efficiency. Secondly, as the result of increasing rotor's tip wheel speed, strengthening the shock waves in rotor will induce the onset of stall flutter. For the turbofans with small bypass ratio, the phenomenon of stall flutter is the main type of aeroelastic instabilities of transonic fans. Both the above-mentioned two restricting factors for further raising the stage pressure ratio connect closely with 3D shock wave's structure and the large-scale separating zone in the rotor, which is induced by 3D interaction of shock wave with boundary layer mainly. However, the 3D shock wave's structure in rotor connects with the leading-edge spatial curve of the rotor blade closely. So, it becomes an important frontier problem among the turbomachinery aerodynamics -- how to design the blade's leading-edge spatial curve carefully. During the designing process of some swept fans, a kind of composite aerodynamic/aeroelastic tailoring program has been used. The aeroelastic tailoring one of main parts of the composite tailoring has been presented, and an example has been shown in this paper too.