A non-uniform gap distribution axial flow fan noise reduction structure

By constructing a non-uniform undulating surface and an acoustic attenuation structure on the inner wall of the axial flow fan, the phase interference of the tip leakage vortex is broken up, solving the noise and efficiency problems of traditional axial flow fans and achieving a balance between high-efficiency noise reduction and aerodynamic performance.

CN121932409BActive Publication Date: 2026-06-09SHANGHAI POWERFUL ELECTRIC CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
SHANGHAI POWERFUL ELECTRIC CO LTD
Filing Date
2026-03-24
Publication Date
2026-06-09

AI Technical Summary

Technical Problem

In traditional axial flow fan design, the periodic phase interference of tip leakage vortices leads to strong aerodynamic noise, and existing noise reduction methods can affect the aerodynamic efficiency and structural strength of the fan.

Method used

A noise reduction structure for axial flow fans with non-uniform gap distribution is adopted. By constructing a non-uniform undulating surface and an acoustic attenuation structure on the inner wall of the casing, the circumferential phase interference of the tip leakage vortex is broken up, and a miniature Helmholtz resonant cavity is embedded in the trough area for targeted absorption.

Benefits of technology

It effectively eliminates the strong discrete frequency noise of the fan, maintains the aerodynamic efficiency and structural strength of the fan, and achieves wide-band adaptive noise reduction.

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Abstract

This invention discloses a noise reduction structure for an axial flow fan with non-uniform gap distribution, belonging to the technical field of axial flow fan structure. It includes a casing with an internal flow channel cavity, and an impeller with Z blades coaxially mounted within the flow channel cavity. The inner wall surface of the casing corresponding to the blade sweep area has a non-uniform undulating surface, which exhibits continuous wavy undulations along the circumference, defining alternating peak and trough regions. The number of trough regions, N, is coprime to the number of blades, Z, used to disperse the circumferential phase interference of tip leakage vortices. An acoustic attenuation structure is asymmetrically embedded only on the back side of the corresponding trough region inside the casing to target and absorb low-frequency eddy current noise at the maximum radial gap. This invention combines macroscopic topological frequency misalignment with microscopic targeted sound absorption, effectively eliminating discrete frequency noise while ensuring the structural strength of the casing and the overall aerodynamic efficiency of the fan.
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