宽弦高速跨音风扇颤振特性研究

颤振是航空发动机、燃气轮机等运行安全的重要威胁,但颤振稳定性与流动结构之间的关系尚不清晰。本文使用行波法和影响系数法,对某宽弦复合掠型高速跨音风扇转子的一阶模态进行了颤振特性研究,计算了在100%转速下从堵塞点到近失速点的颤振表现。使用影响系数法时,分析了不同通道数的计算域对气动阻尼计算的影响,并与行波法得到的结果进行了对比。研究了流动结构与叶片表面气动阻尼之间的关系,旨在提高对流动致颤机理的认识。结果表明影响系数法和行波法均能对叶片的气动阻尼进行较好的预测;流动结构方面,激波、激波附面层分离、叶尖泄漏流以及吸力面前缘叶顶附近的非定常压力波动,对叶片的气动阻尼分布有较大的影响。

Investigation of Flutter Characteristics of a Wide-chord High-speed Transonic Fan

Flutter is a serious threat to the operation safety of aero-engines,gas turbines,etc.,but the relationship between the flutter stability and the flow structure is not yet clear.In this paper,the flutter characteristic of the first bending mode of a wide-chord sweep high-speed transonic fan rotor is investigated by the traveling wave method(TWM)and the influence coefficient method(ICM),and the characteristics from choke point to the near stall point at 100%speed are calculated.When I CM is used,the influence of computational domain with different passages on aerodynamic damping is analyzed,and compared with the results obtained by TWM.The relationship between the flow structure and the aerodynamic damping on the blade surface is studied,aiming to improve the understanding of the flutter mechanism.The result shows that both ICM and TWM can make a good prediction of the aerodynamic damping.In terms of effect of flow structure on aerodynamic damping,shock wave,separation caused by the interaction of shock and boundary,tip leakage flow,and unsteady pressure fluctuations near the tip region of suction side leading edge have a great influence on the aerodynamic damping distribution.