Acoustic Panel Connecting Canals for Low-Frequency Noise Attenuation
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Solution Overview
Problem
Existing acoustic treatment panels for aircraft nacelles are inadequate in effectively attenuating low-frequency noise, as they do not optimize the communication between the porous acoustically resistive structure and the cellular structure, leading to suboptimal noise reduction.
Innovation Solution
The acoustic treatment panel incorporates a porous acoustically resistive structure with connecting canals between the external layer and internal strips, ensuring that small-section openings communicate with through holes, enhancing the panel's operation by compartmentalizing the zone into cells with conduits that facilitate sound wave treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional acoustic treatment panels use simple through-holes in the porous layer, then the structure is simple, but low-frequency noise attenuation is insufficient
Solution Approach 1:
The patent segments the acoustic treatment panel into distinct functional layers: an external porous layer with through-holes, internal strips with openings, and connecting canals between them. This segmentation allows each component to be optimized independently - the through-holes provide simple external access while the connecting canals create extended acoustic paths for low-frequency noise attenuation without complicating the overall manufacturing process.
2Volume of moving object
If the porous acoustically resistive layer is placed directly against the cellular structure, then the structure is compact, but communication between the porous structure and cellular structure is insufficient
Solution Approach 1:
The patent introduces connecting canals that extend in the dimension perpendicular to the panel surface, creating a three-dimensional acoustic path between the external environment and cellular structure. This dimensional extension allows sound waves to penetrate deeper into the cellular structure while maintaining a compact overall panel design, as the canals utilize the thickness dimension rather than increasing the panel's footprint.
3Ease of operation
If small-section openings are used in internal strips, then the acoustic path is extended, but communication with the external layer is insufficient
Solution Approach 1:
The connecting canals act as intermediary elements between the small-section openings in the internal strips and the larger through-holes in the external porous layer. This intermediary structure allows the small openings to provide extended acoustic path length for frequency tuning while the connecting canals ensure adequate sound wave transmission by gradually transitioning to the larger external openings, maintaining transmission efficiency.
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
This configuration optimizes the acoustic treatment panel's performance by ensuring effective communication between the external environment and the cellular structure, leading to improved noise attenuation at low frequencies and increased structural integrity.
Implementation Method 1
Such a panel works on the Helmholtz resonator principle. Thus, the cellular structure comprises a plurality of cells each of which forms an approximately fluid-tight cavity
Implementation Method 2
a porous acoustically resistive structure in contact with an external environment in which during operation sound waves travel
Data Source
AI summary
An acoustic treatment panel including a porous acoustically resistive structure which includes at least one external layer which is in contact with the external environment and which has through holes, internal strips including several openings which communicate with the inside of the cells of the panel and connecting canals, interposed between the external layer and the internal strips, which ensure that the floor-section openings communicate with at least one through hole of the external layer.