Impact of geometric modifications of small axial fans on psychoacoustic metrics

Novaković, Tadej (author), Čurović, Luka (author), Hočevar, Marko (author), Prezelj, Jurij (author)

This paper presents a comprehensive experimental investigation of a basic axial fan and its various modifications. The fan blades were designed according to recommendations from the literature. The prototypes were 3D printed and tested under different operating conditions in accordance with the ISO 5136 and ISO 5801 standards. The aim of the study was to investigate the effects of the axial fan design on the characteristic curve and on the acoustic and psychoacoustic properties of the emitted sound. The characteristic curves were influenced by geometrical features that can lead to obstruction of the flow. The A-weighted sound power level spectra showed that low-frequency (subharmonic) noise humps can be effectively reduced by modifications near the fan hub, while tonal noise in the mid-frequency range can be mitigated by blade root enlargement, small wing tips and low-amplitude edge serrations. The tonal noise was greatly affected by the addition of tip flanges and rotating shrouds, but these modifications reduced the high frequency noise. The psychoacoustic evaluation showed a higher sensitivity to the characteristics of the emitted noise compared to conventional A-weighted one-third octave spectra. While all modifications led to changes in psychoacoustic metrics, loudness, roughness and tonality showed the greatest variability and influence on psychoacoustic annoyance, while sharpness and fluctuation strength were less affected by the different modifications. The results presented emphasize the complex interplay between geometry, aerodynamics, acoustics and psychoacoustics in small axial fans and highlight the need for holistic approaches to fan design in order to solve noise-related problems. The 3D printed machines had similar energy and acoustic characteristics as traditionally manufactured fans, so the use of additive manufacturing techniques proved to be a cost-effective and practical step in the fan design process that could be easily implemented.

• Language: English
• Keywords: axial fans, geometric modifications of blades, psychoacoustic metrics, sound power, aerodynamic performance
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2024
• Number of pages: 15 str.
• Numbering: Vol. 218, art. 109913
• PID: 20.500.12556/RUL-154385
• UDC: 534
• ISSN on article: 1872-910X
• DOI: 10.1016/j.apacoust.2024.109913
• COBISS.SI-ID: 184900611
• Publication date in RUL: 13.02.2024

Record is a part of a journal

• Title: Applied Acoustics
• Publisher: Elsevier
• ISSN: 1872-910X
• COBISS.SI-ID: 23258629

Licences

• License: CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
• Link: http://creativecommons.org/licenses/by-nc-nd/4.0/
• Description: The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.

Secondary language

• Language: Slovenian
• Keywords: aksialni ventilatorji, geometrijske modifikacije lopatic, psihoakustične značilke, zvočna moč, aerodinamična karakteristika

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P2-0401
• Name: Energetsko strojništvo