风扇转子叶片防颤改进设计

Improved design for flutter free of fan rotor blade

通过能量法对某两级跨声风扇试验件原型方案进行气弹稳定性预测,对气弹不稳定转子几何造型进行修改以提高气弹稳定性。通过对原型和改型方案的几何造型、气动性能和振动特性以及气弹稳定性对比分析表明:改型方案最小模态气动阻尼比由-1.46提升至1.83,消除了颤振风险,同时风扇气动性能保持不变且对原方案改动量较小。增加厚度、弦长使叶片相应径向位置的气弹稳定性增加,是改善颤振的有效手段,但是需要关注风扇气动性能变化。在相同槽道堵塞裕度降低量条件下,调整厚度分布提升气弹稳定性幅度最大。

Through aeroelastic stability prediction by energy method in original scheme of a two-stage transonic fan, the geometric modeling of aeroelastic unstable rotor was modified to improve the aeroelastic stability. Through comparative analysis of the geometric modeling, aerodynamic performance, vibration characteristic and aeroelastic stability of original and modified schemes, it showed that the minimum modal aerodynamic damping ratio of modified scheme increased from-1.46 to 1.83, eliminating the flutter risk, while the aerodynamic performance of the fan was kept unchanged and the modification to the original scheme was small. Increasing thickness and chord length can increase aeroelastic stability of blade at corresponding radial position, making it an effective means to improve flutter;however, attention should be paid to the change of aerodynamic performance. With the same reduction of channel blockage margin, adjustment of thickness distribution is the best way to improve aeroelastic stability.