City Research Online

Abstract

Axial flow fans are essential for cooling processes in various industrial settings, making noise reduction a vital factor. Initial studies indicate that adding a porous structure to the fan casing can effectively reduce noise caused by tip leakage vortices. Expanding on this idea, a porous casing based on Triply Periodic Minimal Surfaces (TPMS) was used to assess the fan's aeroacoustic performance. This study introduces the first application of TPMS casings for axial fan tip-leakage noise control. A thorough experimental and numerical analysis was carried out to investigate the aerodynamic properties and identify the mechanisms behind noise reduction. The findings show that the porous casing notably diminishes the strength and size of the tip leakage vortex while also decreasing turbulence intensity near the casing walls. Additionally, the analysis indicates that the degree of noise reduction depends on both the porosity percentage and unit cell size. A diamond TPMS structure with 55% porosity and a unit cell size of 6 mm provides an optimal configuration, enhancing viscous damping and sound energy absorption at low frequencies. This well-designed TPMS structure can effectively reduce both blade passing frequency and turbulence interaction noise, achieving an overall noise reduction of up to 10 dB.

Publication Type:	Article
Additional Information:	The following article has been submitted to/accepted by Physics of Fluids. After it is published, it will be found at https://publishing.aip.org/resources/librarians/products/journals/.
Publisher Keywords:	Noise reduction, Acoustics, Computational fluid dynamics (CFD), Porous Casing, Lattice-Boltzmann method (LBM), Large Eddy Simulation (LES).
Subjects:	Q Science > QA Mathematics > QA75 Electronic computers. Computer science T Technology > TJ Mechanical engineering and machinery T Technology > TK Electrical engineering. Electronics Nuclear engineering
Departments:	School of Science & Technology School of Science & Technology > Department of Engineering
SWORD Depositor:	Symplectic Administrator

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