Helical Cord-Wrapped Air Duct for Aircraft Cabin Noise Reduction
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Solution Overview
Problem
Aircraft interior noise is a significant issue due to various sources, including engines, equipment, and environmental control systems, which current methods like mufflers and insulation batting address inadequately, increasing weight, cost, and complexity.
Innovation Solution
A sound-dampening apparatus featuring a flexible air duct helically wrapped with a flexuous cord, allowing for specific pitch adjustments to target and reduce noise in desired frequency ranges, potentially eliminating the need for traditional noise-reducing components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional noise-reducing components (mufflers and silencers) are integrated into the ECS, then noise levels in the aircraft cabin are reduced, but the weight of the aircraft increases
Solution Approach 1:
The patent extracts the noise-reducing function from traditional heavy components (mufflers and silencers) and implements it directly on the duct surface using a lightweight helical wrapping structure. This eliminates the need for separate noise-reducing components while achieving the same acoustic benefit with minimal weight addition.
Solution Approach 2:
The patent uses a thin, flexible helical wrapping structure that can be applied directly to the duct surface. This thin-film approach provides effective noise reduction through acoustic impedance mismatch and scattering, replacing bulky traditional components with a lightweight surface treatment.
2Object-affected harmful factors
If traditional noise-reducing components (mufflers and silencers) are integrated into the ECS, then noise levels in the aircraft cabin are reduced, but the complexity of the overall aircraft systems increases
Solution Approach 1:
The patent merges the noise-reducing function with the existing duct structure by applying a helical wrapping directly to the duct surface. This integration eliminates the need for separate noise-reducing components and simplifies the overall system architecture while maintaining effective acoustic performance.
Solution Approach 2:
The helical wrapping structure serves multiple functions: it provides noise reduction through acoustic impedance mismatch, acts as a protective layer for the duct, and can be applied to ducts of various sizes and configurations. This multi-functionality reduces system complexity by consolidating multiple roles into a single component.
3Object-affected harmful factors
If traditional noise-reducing components (mufflers and silencers) are integrated into the ECS, then noise levels in the aircraft cabin are reduced, but the operating costs increase
Solution Approach 1:
The patent employs a cost-effective helical wrapping material that can be easily manufactured and installed. The wrapping uses simple geometric structures with basic materials, significantly reducing both initial manufacturing costs and long-term maintenance expenses compared to traditional heavy noise-reducing components.
4Object-affected harmful factors
If traditional noise-reducing components (mufflers and silencers) are integrated into the ECS, then noise levels in the aircraft cabin are reduced, but the performance and range of the aircraft are reduced
Solution Approach 1:
The patent extracts the noise-reducing function from heavy traditional components and implements it through a lightweight helical wrapping structure. This extraction eliminates unnecessary weight that would otherwise reduce aircraft performance and range, while maintaining effective noise reduction capabilities.
Solution Approach 2:
The thin-film helical wrapping provides effective noise reduction with minimal weight addition. By using a lightweight surface treatment instead of bulky components, the patent preserves aircraft performance and range while achieving the required acoustic 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 reduces noise levels in aircraft cabins, saving weight and cost while providing better noise attenuation performance than traditional methods, with the ability to tune noise reduction across different frequency ranges.
Implementation Method 1
A flexuous cord is helically wound around the inner or outer surface of the duct in a continuous length, maintaining a specific pitch to dampen sound in a specific frequency range
Implementation Method 2
the flexuous cord... to dampen sound in a specific frequency range
Data Source
AI summary
Apparatus and methods described herein provide for the management of noise associated with a duct. A sound-dampening apparatus is provided consisting of a duct through which a fluid flows, such as an air duct. A flexuous cord is helically wound around the inner or outer surface of the duct at a pitch corresponding to a selected acoustical frequency range associated with the fluid flow through the duct.