Acoustic Panel Non-Linear Open Area for Aircraft Noise

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Solution Overview

Problem

Existing acoustic panels for aircraft propulsion systems are limited in their ability to effectively attenuate sound across varying sound pressure levels and airflow directions, leading to suboptimal noise reduction and increased aerodynamic drag.

Innovation Solution

The acoustic panel design features a first skin with perforations whose open area percentage changes according to a non-linear function as it extends, coupled with a cellular core that fluidly connects to the skin, allowing for adaptive sound attenuation and reduced aerodynamic drag by varying inter-perforation distances and chamber configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the percentage of open area is increased to improve sound attenuation, then noise reduction is enhanced, but aerodynamic drag increases

Engineering Contradiction:

Improvesound attenuationVSAvoidaerodynamic drag

Core Design Contradiction:

Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The acoustic panel implements varying percentages of open area at different locations along the panel. The first portion has a first percentage of open area while the second portion has a second percentage of open area, allowing each region to be optimized for its specific acoustic and aerodynamic requirements rather than using a uniform design throughout the entire panel

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the physical parameter of open area percentage along the length of the acoustic panel. By transitioning from a higher percentage in the first portion to a lower percentage in the second portion, the design adapts to varying sound pressure levels and airflow conditions at different locations, optimizing both noise reduction and drag characteristics

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If a uniform percentage of open area is used across the panel, then manufacturing is simplified, but sound attenuation effectiveness decreases under varying sound pressure levels

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidsound attenuation effectiveness

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The panel design transitions from a static, uniform open area configuration to a dynamic configuration where the percentage of open area varies along the length of the panel. This dynamic variation allows the acoustic properties to adapt to changing sound pressure levels and operational conditions at different locations

Inventive Principle:

Principle #15Dynamics

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 effectively attenuates sound across different frequencies and airflow conditions while minimizing aerodynamic drag, enhancing the efficiency of the aircraft propulsion system.

Implementation Method 1

an acoustic panel for, for example, an aircraft propulsion system... for attenuating sound generated by its gas turbine engine

Methodology Applied

Scientific EffectAcoustic absorption: Acoustic Absorption

Implementation Method 2

The cellular core includes a plurality of chambers. Each of the chambers extends between the first skin and the second skin. Each of the chambers is fluidly coupled with a respective one or more of the perforations

Methodology Applied

Scientific EffectAcoustic resonance: Resonance

Data Source

PatentUS20240328361A1Acoustic panel with non-linear variable percentage of open area

Publication Date: 2024.10.03 PRATT & WHITNEY CANADA CORP

AI summary

An acoustic panel is provided that includes a first skin, a second skin and a cellular core. The first skin includes a plurality of perforations. The perforations are configured to provide the first skin with a percentage of open area that changes according to a non-linear function as the first skin extends in a first direction. Spacing between at least some of the perforations vary as the first skin extends in the first direction. The cellular core is arranged between and is connected to the first skin and the second skin. The cellular core includes a plurality of chambers. Each of the chambers extends between the first skin and the second skin. Each of the chambers is fluidly coupled with a respective one or more of the perforations.