Sound Reducer With Flow-Around Body for High-Frequency Noise
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Solution Overview
Problem
Existing sound reducers are less effective in reducing high-frequency sound components and are complex and expensive to manufacture.
Innovation Solution
A sound reducer design featuring a flow-around body inside the main pipe, divided into two axial sections, with struts connecting it to the inner wall, and an annular chamber, allowing for effective sound reduction at higher frequencies through mode disruption and resonance, using plastic injection molding for cost-effective assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional sound reducers are used, then they can reduce low-frequency sound effectively, but they are less effective in reducing high-frequency sound components
Solution Approach 1:
The sound reducer is divided into two functional segments: an inner flow-around body that disrupts high-frequency modes and an outer annular chamber that handles low-frequency resonance. This segmentation allows each part to optimize for its specific frequency range, resolving the contradiction between low-frequency effectiveness and high-frequency reduction capability.
Solution Approach 2:
The flow-around body acts as an intermediary structure between the main pipe and the annular chamber. It selectively interacts with high-frequency sound waves through mode disruption, preventing them from reaching the resonator chamber, while allowing low-frequency waves to pass through to the annular chamber for resonance-based reduction.
2Object-affected harmful factors
If complex structures are used to improve high-frequency sound reduction, then sound reduction effectiveness improves, but manufacturing complexity and cost increase
Solution Approach 1:
The invention changes the geometric parameters of the flow-around body (such as its radial position, axial length, and cross-sectional area) to optimize high-frequency mode disruption. By carefully selecting these parameters, the design achieves effective high-frequency reduction without requiring complex multi-component structures, thus resolving the contradiction between performance and manufacturing simplicity.
3Object-affected harmful factors
If the main pipe geometry is changed to disrupt sound modes, then high-frequency sound reduction improves, but the complexity of the pipe structure increases
Solution Approach 1:
The flow-around body is nested within the main pipe, creating a concentric structure where the inner body disrupts sound modes while the outer annular chamber provides resonance-based reduction. This nested arrangement allows both functions to coexist within a single integrated pipe structure, avoiding the need for separate complex components and reducing overall structural complexity.
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
The design effectively reduces high-frequency sound by disrupting double-ring modes and enhancing resonance, achieving efficient sound reduction with simplified and economical manufacturing.
Implementation Method 1
The corresponding double-ring mode is thus disturbed or cannot 'kick in' due to the disturbing structure. This leads to sound transport exclusively in the outer radial region of the main pipe
Implementation Method 2
sound propagating in the main pipe enters the annular chamber through the window(s) and is reflected several times by walls of the annular chamber. An annular chamber and window that are dimensioned suitably result in destructive superposition of the reflected sound waves, i.e. in sound reduction.
Implementation Method 3
destructive superposition of the reflected sound waves, i.e. in sound reduction
Implementation Method 4
The foam allows the fluid and the sound to be transported therein, but the sound undergoes additional attenuation in the sense of sound reduction by energy dissipation
Data Source
AI summary
A sound reducer (1) has a main pipe (10) and an annular chamber (40) that surrounds the main pipe (10). The annular chamber (40) is connected to the interior of the main pipe (10) in a sound-conducting manner via at least one first window (11) while being closed otherwise. Thus, the annular chamber (40) acts as a resonator chamber. A flow-around body (20) is arranged in the interior of the main pipe (10) and is fixed to the inner wall of the main pipe (10) by struts (30; 130, 230).