Wave Attenuation Panel Inserts for Aircraft Nacelle Weight Reduction
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Solution Overview
Problem
Existing wave attenuation panels in aircraft nacelles increase on-board weight and reduce the effectiveness of acoustic treatment by requiring additional reinforcements and altering the aerodynamic surface continuity when placed close to the power plant to minimize weight.
Innovation Solution
A wave attenuation panel with a permeable layer and alveolar structure, inserted between the air intake and power plant, maintains aerodynamic surface continuity and reduces weight by using inserts to distribute compressive forces, allowing it to be thinner and wider closer to the power plant without compromising acoustic treatment performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a wave attenuation panel is placed close to the power plant to minimize weight, then the panel can be thinner and wider, but it requires additional reinforcements that increase on-board weight and alter the aerodynamic surface continuity
Solution Approach 1:
The wave attenuation panel is divided into multiple segments or sections, allowing it to be distributed across different locations in the nacelle. This segmentation enables the panel to achieve weight reduction through optimized local placement while maintaining overall acoustic treatment effectiveness without requiring集中 reinforcements that would increase total weight
Solution Approach 2:
The acoustic treatment is applied with varying thickness and density at different locations within the nacelle, concentrating treatment where most needed near the power plant while reducing it in areas where less attenuation is required. This local optimization reduces total material weight while maintaining effectiveness, and allows aerodynamic surfaces to remain continuous in non-critical areas
2Weight of moving object
If a wave attenuation panel is placed close to the power plant to minimize weight, then the panel can be thinner and wider, but it alters the aerodynamic surface continuity
Solution Approach 1:
The aerodynamic surface is maintained with different qualities at different locations: fully continuous in critical flow areas and selectively interrupted only where acoustic treatment is most needed. This localized approach to surface continuity allows weight reduction through thinner panels while preserving aerodynamic performance in essential areas
Solution Approach 2:
The wave attenuation panel incorporates three-dimensional shaping and contouring that allows it to integrate with the aerodynamic surface rather than simply interrupting it. By giving the panel volumetric form that follows the nacelle contours, the design maintains aerodynamic flow paths while providing acoustic attenuation, reducing the need for heavy reinforcement structures
3Reliability
If the wave attenuation panel is made thicker to improve wave absorption, then acoustic treatment performance increases, but on-board weight increases
Solution Approach 1:
The acoustic treatment thickness is optimized locally rather than uniformly throughout the nacelle. Thicker treatment is applied only in regions where wave attenuation is most critical near the power plant, while thinner or absent treatment is used in areas where less attenuation is needed, reducing total weight while maintaining acoustic effectiveness
Solution Approach 2:
The wave attenuation panel uses composite material structures combining different acoustic materials with varying densities and absorption characteristics. This allows thin sections to provide effective attenuation through material properties rather than thickness, reducing overall panel weight while maintaining acoustic treatment performance
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 solution effectively limits wave propagation from the power plant while minimizing additional weight and maintaining the performance of the acoustic treatment by ensuring aerodynamic surface continuity and using inserts to manage compressive forces, thus optimizing both noise reduction and structural integrity.
Implementation Method 1
an acoustically resistive porous layer 30, at least one alveolar structure 32, and a reflective or impermeable layer 34. The acoustically resistive layer is a porous structure that has a dissipative role, partially transforming into heat the acoustic energy of the sound wave that passes through said layer.
Implementation Method 2
Techniques that have been developed to reduce the noise emitted by an aircraft, and in particular the noise emitted by the propulsion systems, consist in placing a coating 28 whose purpose is to absorb a portion of the sound energy, in particular by using the principle of the Helmholtz resonators
Implementation Method 3
Another solution consists in providing a wave attenuation panel 36 that comprises, like the acoustic attenuation panel from the outside to the inside, a layer that is permeable to certain waves, at least one alveolar structure, and a reflective or impermeable layer. Thus, this panel is intended to absorb in its passage the wave(s) produced by the pumping effect of the power plant and to limit its propagation.
Data Source
AI summary
An aircraft nacelle includes a wave attenuation panel which limits or prevents the propagation of at least one wave produced during the pumping of the power plant and includes a layer that is in contact with the air flow that can allow passage of the at least one wave, at least one alveolar structure, and a reflective or impermeable layer, wherein the wave attenuation panel is inserted between the air intake and the power plant, and the layer that is in contact with the air flow ensures the continuity of the aerodynamic surfaces that are arranged downstream and upstream and the wave attenuation panel includes inserts that can be inserted between the air intake and the power plant so as not to crush the wave attenuation panel.