混合盘绕型声学超材料在低频隔声中的应用

Application of hybrid coiled acoustic metamaterials in low frequency sound insulation

为有效隔离变压器产生的可听噪声,提出了基于声学超材料的噪声处理方法。首先对变压器噪声进行测量,根据测量结果分析其频谱特性;之后针对主要噪声频率集中在400 Hz和500 Hz的区域,设计了一种混合盘绕型声学超材料单元,该混合盘绕型声学超材料单元内部声波导长度比单元尺寸长7倍多,具有极高的折射率。通过有限元数值计算,分析了所设计的混合盘绕型声学超材料单元的声学特性,并计算其传声损失,发现在400至500 Hz频段其具有极高声压反射系数且传声损失到达25 dB左右。使用阻抗管测量进行实验验证,将实验结果同仿真数据进行对比,发现二者具有较高的一致性。

The audible noise generated by the transformer has a large impact on the station staff and nearby residents.This paper aims to study transformer noise and propose a method of noise reduction Firstly,the transformer noise is measured,and its spectral characteristics are analyzed according to the measurement results.A hybrid-coiled-type acoustic metamaterial unit is designed for the main noise frequencies which concentrated in the 400 Hz to 500 Hz regions.The inner acoustic waveguide of the hybrid-coil-type acoustic metamaterial unit has a length of more than 7 times longer than the unit size,and has an extremely high refractive index.The acoustic characteristics of the hybrid-coil-type acoustic metamaterial element are studied by finite element numerical calculation,and the sound transmission loss is calculated.It is found that it has a very high sound pressure reflection coefficient and the sound transmission loss reaches about 25 dB in the frequency range of 400 to 500 Hz.Experiments were performed using the impedance tube measurements,and the experimental results are compared with the finite element numerical data.And it is found that the two have high consistency.This work provides new ideas and research directions for low frequency sound insulation.