上下游干涉对转子叶片颤振特性的影响

使用自行开发的非定常流动数值模拟程序,分别考虑上、下游叶排干涉作用对转子叶片的颤振特性进行了研究,分析尾迹和势干扰对气动阻尼的影响规律.对转子叶片表面非定常压力进行傅里叶变换,使用能量法计算气动阻尼,研究不同叶片排轴向间距下气动阻尼的变化.通过考虑转静干涉效应的气动阻尼与单转子结果对比,总结了干涉作用对叶片颤振特性的影响规律;结果表明:上游导叶与转子一倍弦长间距时,获得正气动阻尼,与单转子预测的气动弹性稳定性结果相反.说明在进行颤振特性预测时必须考虑转静干涉作用;尾迹和势干扰的强度均随着轴向间距值的减小而加强,且都会加剧叶片气动弹性失稳. 

Influence of up-and downstream blades on the rotor blade flutter characteristics

Flutter characteristics of rotor blades including up-and downstream interaction were simulated by self-developed unsteady flow simulation programs. Influence of wakes and potential waves on blade aerodynamic damping were studied. Energy exchange method was used to calculate the damping values. Variation of aerodynamic damping with different axial gaps was identified by FFT transformation of unsteady pressures on rotor blade surfaces. Interaction effects on the flutter characteristics of rotor/stator and IGV/rotor configurations were assessed by comparing the damping data with that of the single rotor. The results show that the positive damping was obtained at 100% chord axial gap for IGV/rotor configuration, in contrast with the aeroelastic stability prediction of the isolated rotor. This indicates the interaction must be considered in flutter analysis. The results also illustrate that wake and potential wave effects are intensified with reducing axial gaps, and both destabilize the rotor blades.