周向畸变对跨声速风扇低阶强迫振动的影响研究

边界层抽吸式推进系统(BLI)因具有降低未来商用飞机燃油消耗率的巨大潜力而备受关注.但风扇叶片作为关键组件,需要受到由于边界层吸入而导致的畸变来流的挑战.基于本团队前期在NASA Rotor 67进行的数值模拟,在设计转速附近风扇因受到二阶激励而以一阶弯曲的形式发生低阶模态振动,同时,激发的强度足以引起叶片振动.由于来...

Effects of Circumferential Distortion on Low-Order Forced Vibration of Transonic Fan

Boundary layer ingestion propulsion systems have attracted much attention due to significant potential to reduce the fuel consumption of future commercial aircraft.However,the fan blade,as a key component,needs to be designed to overcome the challenge of distorted inflow due to boundary layer ingestion.Based on the numerical simulation of NASA Rotor 67 under a BLI-type inlet distortion,previous study revealed that the resonance between second-order excitation and first-order bending mode is detected near the design rotor speed.At the same time,the magnitude of excitation is strong enough to induce blade vibrations.Due to that the circumferential extent of inlet distortion varies with the BLI propulsion systems,the effect of it on low-order vibration is significant to be investigated.Thus,five inlet distortions with different distorted extents are considered in this study.By the 3D unsteady simulation and modal force analysis of NASA Rotor 67,the results demonstrate that the low-order vibration modes remain unchanged under different distorted extents.However,with the increase of distortion extent,the magnitude of modal force starts to increase and then decreases.To cause the blade vibration,there are two significant sources of second-order excitation,which are included in distorted inflow and induced by the transient state in the blade passage.