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复杂流动系统中气动噪声源特性的研究是研究噪声传播及建立气动噪声模型的基础.本文采用实验的手段研究了贯流风扇的气动噪声源特性。实验在本底噪声为19 dB(A)的静音室中进行,采用高精度,高频响的声压传感器分别测量了室内机进口,蜗舌壁面,近叶轮出口,远场等位置的声压波动.对得到的原始压力脉动数据进行了快速傅里叶变换,基于FFT变换的联合时频分析,基于连续小波变换的联合时频分析.分别在时间域和频率域进行了不同测量点的对比分析。结果表明,实验机表现为明显的宽频噪声特性,其主要噪声源为流场中的涡流.基于连续小波变换的时频分析方法能更精确地表现信号的非定常特性,能对信号进行不同层次的深入分析,得到更精确的结果.
The study of the characteristics of aero-noise sources in complex flow systems is the basis for the study of noise propagation and the establishment of aerodynamic noise models.In this paper, the characteristics of aero-noise sources for cross-flow fans are studied experimentally. The experiment was carried out in a quiet room with a noise floor of 19 dB (A). The sound pressure of the indoor unit inlet, the volute wall, the impeller exit, the far field and so on were measured by using high-precision and high-frequency sound pressure sensors The original pressure pulsation data obtained by the fast Fourier transform, FFT-based joint time-frequency analysis, based on continuous wavelet transform combined with time-frequency analysis in the time domain and frequency domain were compared at different measurement points analysis. The experimental results show that the experimental machine exhibits obvious wide-band noise characteristics, and the main noise source is the eddy current in the flow field.The time-frequency analysis method based on continuous wavelet transform can more accurately represent the unsteady characteristics of the signal, In-depth analysis, get more accurate results.