风扇进口噪声预测模型的改进

An Improved Prediction Model for Fan Inlet Noise

关键词:  风扇  宽频噪声  噪声  Heidmann模型  雷诺数

Key words:  Fan  Broadband noise  Noise  Heidmann model  Reynolds number

摘要:

针对Heidmann模型对风扇进口低频噪声(<1kHz)预测结果偏低的情况，通过引入风扇叶尖弦长雷诺数和相关几何参数改进了Heidmann模型中风扇进口宽频噪声的频谱修正函数，确定了其中频谱修正系数为0.085。对比改进模型和Heidmann模型的风扇进口噪声预测结果发现:在亚声速工况下，改进的模型很好地改善了风扇进口低频噪声的预测结果，改进幅值可以达到约45dB；而在超声速工况下，由于风扇进口产生的组合单音噪声成为风扇进口噪声的主要组成部分，除了在小于100Hz的频域内，改进的模型与Heidmann模型的预测结果差别不大。

Abstract:

Sound pressure level(SPL) in the low frequency range(<1kHz)，predicted by Heidmann model，is generally much lower than experimental results，so the fan tip chord Reynolds number and some related geometry parameters are introduced to improve the fan inlet broadband noise spectrum corrected function of Heidmann model，and the factor of new spectrum corrected function is confirmed to be 0.085. Comparing the predicted results of improved model with those of Heidmann model，it can be found that the improved model made progress with the predicted results in the low frequency range at the subsonic operation point. The maximum increment of SPL is about 45dB. When the fan operates at the supersonic operation point，the predicted results of improved model are almost the same as those of Heidmann model except in the very low frequency range(<100Hz).This is because the combination tone noise appears and becomes the main part of the fan inlet noise when the relative tip Mach number is supersonic.