Damping of flexural vibrations in turbofan blades using the acoustic black hole effect
Damping of flexural vibrations in turbofan blades using the acoustic black hole effect
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DOI：
10.1016/j.apacoust.2013.09.009
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发表时间：
2014-02-01
影响因子：
3.4
通讯作者：
Krylov, V. V.
中科院分区：
文献类型：
--
作者：
Bowyer, E. P.;Krylov, V. V.
本文报道了按幂函数型线变截面的涡扇叶片弯曲振动衰减的实验研究结果。幂律轮廓(楔形)的后缘带有小块的吸收层，形成了一维弯曲波的声学黑洞，可以吸收很大一部分入射弯曲波的能量。实验是在四个铝制模型叶片上进行的。其中两个是扭曲的，这样就可以考虑更逼真的风扇叶片。所有模型叶片，包括锥形尾缘叶片和传统形状叶片，均由电磁振动器激励，并测量了相应的频率响应函数。结果表明，在叶片上引入幂函数渐变后，共振峰大大降低。利用闭路风洞中的测量结果，初步研究了该方法的空气动力学含义。特别研究了幂函数型线后缘对风机叶片气流激励振动的影响。结果表明，在幂函数型线后缘加适当的阻尼层，能有效地减小风机叶片的气流激振。研究结果表明，涡扇叶片尾缘的幂函数渐变是一种可行的叶片减振方法。(C)2013爱思唯尔有限公司。保留所有权利。
The results of the experimental study into the damping of flexural vibrations in turbofan blades with trailing edges tapered according to a power-law profile are reported. Trailing edges of power-law profile (wedges), with small pieces of attached absorbing layers, materialise one-dimensional acoustic black holes for flexural waves that can absorb a large proportion of the incident flexural wave energy. The experiments were carried out on four model blades made of aluminium. Two of them were twisted, so that a more realistic fan blade could be considered. All model blades, the ones with tapered trailing edges and the ones of traditional form, were excited by an electromagnetic shaker, and the corresponding frequency response functions have been measured. The results show that the resonant peaks are reduced substantially once a power-law tapering is introduced to the blade. An initial study into the aerodynamic implications of this method has been carried out as well, using measurements in a closed circuit wind tunnel. In particular, the effects of the trailing edge of power-law profile on the airflow-excited vibrations of the fan blades have been investigated. It has been demonstrated that trailing edges of power-law profile with appropriate damping layers are efficient in reduction of the airflow-excited vibrations of the fan blades. The obtained results demonstrate that power-law tapering of trailing edges of turbofan blades can be a viable method of reduction of blade vibrations. (c) 2013 Elsevier Ltd. All rights reserved.