Axial Fan Silencer Layout for Targeted Noise Reduction
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Solution Overview
Problem
Existing blower systems with fans generate noise at specific frequencies due to the number of blades and rotation speed, which is difficult to silence using conventional porous sound absorbing materials without compromising air volume or increasing device size.
Innovation Solution
A blower system with a silencer that includes a resonator positioned to overlap with the fan's shaft, utilizing a film-type resonator or Helmholtz resonator to selectively silence dominant sounds by matching resonance frequencies, while maintaining a compact design and ensuring air volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If porous sound absorbing material is used to silence fan noise, then soundproofing performance is improved, but air volume is reduced and device size must be increased
Solution Approach 1:
The silencer is designed with a non-uniform cross-sectional area along the airflow direction, creating local variations in acoustic impedance. The cross-sectional area gradually changes from the upstream end to the downstream end, providing different sound absorption characteristics at different locations while maintaining efficient airflow passage.
Solution Approach 2:
The invention transitions from using extensive porous materials filling the entire passage to a structured silencer with controlled cross-sectional area variations. This dimensional approach allows sound absorption functionality to be achieved through geometric configuration rather than material volume, preserving air volume.
2Object-affected harmful factors
If porous sound absorbing material is increased in volume to improve silencing effect, then soundproofing performance is improved, but device size must be increased
Solution Approach 1:
Instead of uniformly increasing material volume throughout the device, the silencer concentrates sound absorption functionality in a compact structure with strategically varied cross-sectional areas. This localized optimization achieves effective noise reduction without proportionally increasing overall device volume.
Solution Approach 2:
The silencer utilizes changes in cross-sectional area parameter along its length to create acoustic impedance variations that enhance sound absorption. This parameter-based approach replaces volume-based absorption with geometry-based absorption, reducing device size.
3Productivity
If silencer is installed on outer peripheral portion of fan passage to ensure ventilation, then air volume is maintained, but device size must be increased
Solution Approach 1:
The silencer is integrated within the existing fan passage structure rather than being installed as a separate peripheral component. The silencer and fan passage are merged into a unified structure where the silencer occupies space within the passage without requiring additional external volume, thus maintaining compact device size while preserving ventilation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively silences specific frequency noise generated by the fan while maintaining air volume and reducing the overall size of the blower system, improving soundproofing performance without increasing the device's dimensions.
Implementation Method 1
the silencer includes a resonator that selectively silences a dominant sound generated by the axial fan
Implementation Method 2
the silencer performs resonance sound absorption
Data Source
AI summary
A blower with a silencer has the blower including an axial fan including a casing, a motor attached to the casing, and a rotor having a shaft portion attached to the motor and rotated and a blade formed to protrude to an outer side of the shaft portion in a radial direction, and a silencer attached to the casing, in which the silencer includes a resonator that selectively silences a dominant sound generated by the axial fan, the silencer is disposed at a position in which at least a part of the silencer overlaps with the shaft portion, as viewed from a rotation axis direction of the rotor, and in a case in which, in a cross section perpendicular to a rotation axis of the rotor, a circle around the rotation axis, which has a radius of a line connecting the rotation axis and a point of a most distal end of the blade, is defined as a rotation region, an area of the silencer in the cross section perpendicular to the rotation axis is smaller than an area of the rotation region.