Numerical simulation study on aeroelastic stability mechanism of a transonic fan rotor

This study investigates the aeroelastic stability of fan rotor blades via the energy method. Research has identified shock waves, backflow, and radial flow as important factors causing aeroelastic instability in rotor blades. The variation in the aerodynamic damping of the rotor blade with the interblade phase angle is consistent with that on the suction surface. The larger the unsteady pressure amplitude is, the more difficult it is for the interblade phase angle to affect the phase of the unsteady pressure in the corresponding area. At a constant rotational speed, the radial flow on the suction surface gradually intensifies as the flow rate decreases. This strong radial flow causes aeroelastic instability near the stall point by altering the phase of the unsteady aerodynamic forces on the rotor blade surface. The aeroelastic instability boundary at different speeds is near the stall point. Regions with large unsteady aerodynamic pressure amplitudes on the rotor blade surface are located mainly near the leading edge of the suction surface, shock waves, and backflow areas. The phase of unsteady pressure in these regions undergoes a 180-degree shift due to the influence of shock waves and strong radial flow.