Turbomachine Acoustic Panel With Movable Helmholtz Resonator Masses
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Solution Overview
Problem
Conventional acoustic panels for turbomachines are limited in their ability to absorb noise across a wide frequency range due to fixed cavity dimensions, and their manufacturing process is complex and inflexible, making it difficult to repair and adapt to varying shapes without compromising acoustical insulation.
Innovation Solution
The acoustic panel incorporates vibrating masses connected to cavity walls via elastic means, allowing dynamic adjustment of Helmholtz resonator volumes to filter multiple frequencies, and utilizes additive manufacturing to produce the panel components, enabling flexible production and repair.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional acoustic panels with fixed cavity dimensions are used, then the manufacturing process is simplified, but the frequency range of noise absorption is limited
Solution Approach 1:
The patent introduces movable elements (balls or granular material) within the cavities that can shift position to dynamically adjust the effective cavity volume. This dynamic adjustment allows the same panel structure to absorb noise across multiple frequency ranges, resolving the contradiction between manufacturing simplicity and frequency adaptability.
Solution Approach 2:
The invention changes the physical parameter of cavity volume by allowing movable elements to alter the effective space within fixed cavity structures. This parameter change enables the panel to adapt its acoustic performance to different frequency ranges without requiring multiple fixed designs, maintaining manufacturing simplicity while improving versatility.
2Strength
If the panel structure is integrated with acoustical insulation, then mechanical resistance is ensured, but local repair of damaged skin is impossible without altering acoustical insulation
Solution Approach 1:
The patent separates the structural function (skins providing mechanical resistance) from the acoustic function (cavities with movable elements providing noise absorption). This segmentation allows the skins to be repaired independently without affecting the acoustic insulation, as the movable elements can be repositioned or replaced within the cavity structures.
Solution Approach 2:
The invention extracts the acoustic insulation function from the structural skin by placing movable acoustic elements within separate cavity structures. This extraction allows damaged skin areas to be repaired or replaced without compromising the acoustic insulation, which resides in the independent cavity system.
3Object-affected harmful factors
If honeycomb structure is perforated at all points for acoustical insulation, then noise absorption is effective, but manufacturing flexibility is reduced
Solution Approach 1:
The patent replaces fixed perforations with movable elements that can be positioned to create effective acoustic paths dynamically. This dynamic approach maintains noise absorption effectiveness while allowing greater manufacturing flexibility, as the honeycomb structure does not require precise pre-perforation at every point.
Solution Approach 2:
The movable elements within the cavities self-adjust to create effective acoustic paths without requiring pre-configured perforations. This self-service mechanism maintains noise absorption performance while simplifying manufacturing, as the acoustic functionality emerges from the movable elements rather than requiring precise pre-perforation patterns.
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 solution extends the frequency range of noise absorption and simplifies the manufacturing process, allowing for improved acoustical insulation and local repair without altering the panel's performance.
Implementation Method 1
between which are located and extend cavities forming Helmholtz resonators
Implementation Method 2
under the effect of the acoustical pressure p, a force F, equal to the product p.A
Implementation Method 3
vibrating masses being provided in at least some of said cavities and connected to cavity walls by elastic means housed in said cavities
Data Source
AI summary
An acoustic panel for a turbomachine, in particular for an aircraft, includes two skins that are substantially parallel and between which extend cavities forming Helmholtz resonators, one of the skins being perforated by orifices opening into the cavities and forming necks of the Helmholtz resonators, vibrating masses being provided in at least some of the cavities and connected to cavity walls by an elastic junction housed in the cavity.