Page 31 - 《应用声学》2020年第2期

第 39 卷 第 2 期 Vol. 39, No. 2
2020 年 3 月 Journal of Applied Acoustics March, 2020

⋄ 研究报告 ⋄

电子器件散热风扇气动噪声管道声学

模态截止控制技术 ∗

孙宗翰 1 田 杰 1,2 张效溥 1 欧阳华 1,2†

(1 上海交通大学机械与动力工程学院 上海 200240)
(2 燃气轮机与民用航空发动机教育部工程研究中心 上海 200240)
摘要：该文针对电子器件散热用的一款变速轴流风扇的气动噪声及其降噪方法进行实验研究。首先利用风扇
旋转轴等高平面内圆周分布的传感器阵列测量风扇不同转速下远场噪声分布，总声压级与转速的对数关系验
证散热风扇主要气动噪声属于偶极源噪声，频谱分析显示离散单音噪声为主要噪声影响因素。基于管道声学
理论的管道模态截止方法，研究进出风口安装圆形短管对风扇气动噪声的影响，实验结果显示不同位置、不同
长度的短管对风扇远场噪声影响不同。额定转速下，在进风口安装 2 cm 管道可以使远场 1 m 处平均总声压级
下降 4.1 dB(A)，降噪效果显著。模态测量结果显示，此种情况下对应离散单音处的风扇主要模态幅值大大降
低，风扇离散单音噪声降低从而噪声总声压级大幅减小。该方法为散热风扇降噪提供了一种新的途径。
关键词：散热风扇；降噪；管道模态截止；频谱分析
中图法分类号: TH42 文献标识码: A 文章编号: 1000-310X(2020)02-0189-10
DOI: 10.11684/j.issn.1000-310X.2020.02.004

Aerodynamic noise control technology of electronic device cooling fan based on

duct acoustic mode cutoff
SUN Zonghan 1 TIAN Jie 1,2 ZHANG Xiaopu 1 OUYANG Hua 1,2

(1 School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China)
(2 Engineering Research Center of Gas Turbine and Civil Aero Engine, Ministry of Education, Shanghai 200240, China)

Abstract: An experimental study on the aerodynamic noise and noise reduction method of a variable-speed
axial flow fan for electronic device heat dissipation is conducted. The far-field radiation noise at different
rotational speed is measured by a microphone array uniformly distributed along the circumference in the
contour plane of the fan axis. The logarithmic relationship between the total sound pressure level (SPL) and
the rotational speed verifies that the main aerodynamic noise of the fan belongs to the dipole source noise, and
the spectrum analysis indicates that the discrete tonal noise is the dominant noise. Based on the duct mode
cutoff in duct acoustic theory, the effects on the aerodynamic noise of installing a circular short duct at the
inlet and outlet of the fan are studied, pointing out that the short ducts with different lengths on the different
sides have different effects on the far-field noise. At rated fan speed, installing a 2 cm duct at the inlet can
reduce the average total SPL by 4.1 dB(A) at the far field of 1 m, which is significant. Mode measurement
results show that in this case the main mode amplitude corresponding to the discrete tone is greatly reduced,
and the reduction of discrete tonal noise leads to a significant reduction of the total SPL. This method provides
a new way for cooling fan noise reduction.
Keywords: Cooling fan; Noise reduction; Duct mode cutoff; Spectrum analysis

2019-06-17 收稿; 2019-11-28 定稿
∗ 中央高校基本科研业务费专项
作者简介: 孙宗翰 (1995– ), 男, 贵州安顺人, 硕士研究生, 研究方向: 叶轮机械气动声学。
† 通信作者 E-mail: oyh@sjtu.edu.cn