Aircraft Acoustic Panel Perforation Design for Noise and Weight Trade-offs
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Solution Overview
Problem
Existing aircraft propulsion system acoustic panels face challenges in balancing sound attenuation with aerodynamic and structural characteristics, particularly in environments with varying fluid velocities, where they often compromise between noise reduction and propulsion efficiency and structural strength.
Innovation Solution
The acoustic panel design incorporates a perforated skin with adjustable perforation size and percentage of open area, coupled with a cellular core, to optimize sound attenuation and structural strength. In high-velocity environments, reducing perforation size decreases flow resistance and mass while maintaining sound attenuation, and in low-velocity environments, larger perforations enhance sound absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If larger perforations are used in acoustic panels, then sound absorption is enhanced in low-velocity environments, but flow resistance increases and propulsion efficiency decreases in high-velocity environments
Solution Approach 1:
The acoustic panel employs adjustable perforation sizes that can be dynamically configured based on operating conditions. In high-velocity environments, the system reduces perforation size to minimize flow resistance and maintain propulsion efficiency. In low-velocity environments, larger perforations are activated to enhance sound absorption. This dynamic adaptability allows the panel to optimize both aerodynamic performance and acoustic attenuation according to real-time flight conditions.
Solution Approach 2:
The invention changes the physical parameter of perforation size to resolve the contradiction between sound absorption and flow resistance. By varying the perforation diameter as a controllable parameter, the system achieves different acoustic performance levels while maintaining acceptable flow characteristics across varying operating conditions, thus balancing sound attenuation requirements with propulsion efficiency.
2Object-affected harmful factors
If larger perforations are used to enhance sound absorption, then acoustic performance improves, but structural strength and mass are reduced
Solution Approach 1:
The acoustic panel implements different perforation sizes in different regions or zones of the panel structure. Areas requiring higher sound absorption have larger perforations, while regions needing greater structural strength have smaller or no perforations. This local differentiation allows the panel to achieve overall acoustic performance while maintaining necessary structural integrity in critical areas.
Solution Approach 2:
The invention combines materials with different properties to create a composite acoustic panel structure. The panel integrates porous acoustic materials with structurally robust substrates, allowing the porous sections to provide sound absorption while the solid matrix maintains structural strength. This composite approach enables simultaneous optimization of acoustic performance and mechanical properties.
3Loss of energy
If perforation size is reduced to decrease flow resistance in high-velocity environments, then propulsion efficiency improves, but sound absorption capability decreases
Solution Approach 1:
The system dynamically adjusts perforation size based on flow velocity conditions. In high-velocity environments, smaller perforations are activated to reduce flow resistance and maintain propulsion efficiency. When flow velocity decreases, the system transitions to larger perforations to maximize sound absorption. This dynamic reconfiguration ensures optimal performance across varying operating conditions.
Solution Approach 2:
The acoustic panel is divided into multiple segments or zones with different perforation characteristics. Some segments have smaller perforations optimized for high-velocity flow conditions, while other segments have larger perforations optimized for sound absorption in lower velocity conditions. This segmentation allows different portions of the panel to serve different functions simultaneously, balancing propulsion efficiency and acoustic attenuation.
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 design maintains or increases sound attenuation across varying fluid velocities while reducing mass and weight, improving structural strength and propulsion efficiency by optimizing perforation size and open area percentages in different aircraft propulsion system components.
Implementation Method 1
An aircraft propulsion system may include one or more acoustic panels for attenuating sound generated by its gas turbine engine
Data Source
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AI summary
An assembly is provided for an aircraft propulsion system. This assembly includes a first acoustic panel and a second acoustic panel. The first acoustic panel (10A) includes a first perforated skin (12A), a first non-perforated skin (14A) and a first cellular core (16A) arranged between and connected to the first perforated skin and the first non-perforated skin. The first perforated skin is configured with a plurality of first perforations (18A). A first of the first perforations has a first width (54). A second acoustic panel (10B) includes a second perforated skin (12B), a second non-perforated skin (14B) and a second cellular core (16B) arranged between and connected to the second perforated skin and the second non-perforated skin. The second perforated skin (12B) is configured with a plurality of second perforations (18B). A first of the second perforations (18B) has a second width (60) that is smaller than the first width (18B).