激波对跨声速风扇叶片颤振特性的影响

Effects of Shock Wave on Blade Flutter Characteristics in Transonic Fan

关键词:  叶片颤振  激波  非定常流  能量法

Key words:  Blade flutter  Shock wave  Unsteady flow  Energy method

摘要:

为了研究激波对叶片气动弹性稳定性的影响，基于谐波平衡计算方法，结合结构动力学分析，采用单向耦合方式下的能量法对跨声速风扇的颤振特性进行了数值研究。计算结果表明:设计点工况下，二阶弯曲模态时叶片的最小气动阻尼系数小于0，数值为-0.338%，意味着叶片存在失稳风险；此外，100%等转速线不同工况下叶片的颤振特性不尽相同，激波位置变化对气流做功的影响是导致叶片气动弹性稳定性差异的主要诱因。

Abstract:

In order to investigate effects of shock wave on blade aeroelastic stability，based on harmonic balance computation technique with structure dynamics analysis method，the flutter characteristics of transonic fan is numerically simulated through energy method in one-way coupling manner. The results show that the minimum value of aerodynamic damping coefficient was -0.338% for the second bending mode on the design point，less than 0，meaning an existence of instability risk for the blades. Furthermore，the blade flutter characteristics is found to be not always identical under different working conditions in 100% rotating speed line. The effect on aerodynamic work from change of shock wave position is a main inducement leading to the difference of blade aeroelastic stability.