Noise Source Analysis and Control for Two Axial-Flow Cooling Fans in Series

  • C. WangEmail author
  • W. Zhang
  • L. Huang
Conference paper
Part of the Lecture Notes in Mechanical Engineering book series (LNME)


The noise signature of two identical small axial-flow cooling fans in series was analyzed and a technique of synchronous averaging with time-base stretching was used to decompose the raw sound signals into various noise source components. Acoustic directivity measurements were conducted for the case of distorted inlet flow caused by a flat plate covering half of the circular inlet flow passage. The effects of the flat plate and the axial distance between the flat plate and the fan inlet were studied as well. It is found that the inlet flow distortion increases the total sound pressure level (SPL), random and rotary noise of the upstream fan a lot but it barely affects the rotary noise of the downstream fan. A flow straightener consisting of many small hexagons is mounted at the inlet of the upstream fan to reduce the adverse effect of the inlet flow distortion. The total SPL is reduced by 1.2 dB on average.


Flat Plate Inlet Flow Flow Straightener Noise Directivity Rotary Noise 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


  1. Huang L (2003) Characterizing computer cooling fan noise. J Acoust Soc Am 114(6):3189–3200CrossRefGoogle Scholar
  2. Huang L, Wang J (2005) Acoustic analysis of a computer cooling fan. J Acoust Soc Am 118:2190–2200CrossRefGoogle Scholar
  3. Wang C, Zhang W, Huang L (2015) Noise source analysis and control for two axial-flow cooling fans in series. Fan Noise 2015, Lyon, FranceGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  1. 1.Lab of Aerodynamics and Acoustics, HKU Zhejiang Institute of Research and Innovation, Shenzhen Institute of Research and Innovation, and Department of Mechanical EngineeringThe University of Hong KongHong KongChina
  2. 2.School of Energy and Power EngineeringBeihang UniversityBeijingChina

Personalised recommendations