Perforated Air Distributor for Low-Frequency Duct Noise
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Solution Overview
Problem
Ventilation systems in aircraft generate low frequency noise due to airflow redirection at joints between air ducts, which conventional mufflers are unable to effectively reduce, impairing passenger comfort.
Innovation Solution
A perforated air distributor with a Y- or L-shaped body is inserted at the joint of air ducts, redirecting airflow through perforations to minimize turbulence and generate small vortices, reducing low frequency noise by distributing airflow in both directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional mufflers are used to reduce noise, then noise reduction is attempted, but low frequency noise generated by airflow redirection cannot be effectively reduced
Solution Approach 1:
A perforated air distributor body is introduced as an intermediary component between the first air duct and second air duct. This mediator redirects airflow through its perforated structure, breaking up large-scale turbulence into smaller vortices that can be effectively dampened by conventional mufflers, thereby resolving the inability of conventional mufflers to reduce low frequency noise generated at duct joints
Solution Approach 2:
The air distributor body is made porous through the incorporation of numerous perforations across its surface. This porous structure allows airflow to pass through multiple small openings rather than creating large-scale turbulence, transforming the noise-generating flow pattern into smaller vortices that are easier to dampen, thus enabling effective noise reduction
2Ease of operation
If airflow is redirected at joints between air ducts, then ventilation function is achieved, but low frequency noise is generated
Solution Approach 1:
The air distributor body incorporates numerous perforations across its surface, creating a porous structure that redirects airflow through many small openings. This approach maintains the ventilation function by allowing air to pass from the first duct to the second duct while preventing the generation of large-scale turbulence and low frequency noise that would occur with conventional direct redirection
Solution Approach 2:
The airflow redirection process is segmented into multiple small flow paths through the numerous perforations in the air distributor body. Instead of a single large-scale redirection that generates noise, the airflow is divided into many small streams that pass through individual perforations, collectively achieving the ventilation function while minimizing noise generation
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 low frequency noise by creating small vortices that can be easily dampened by conventional mufflers, improving passenger comfort and integrating seamlessly into existing ventilation systems.
Implementation Method 1
The turbulences generated at the joint of the air ducts are a significant source of low frequency noise
Implementation Method 2
creating small vortices that can be easily dampened by conventional mufflers
Data Source
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AI summary
An air distributor according to the invention has a perforated body, insertable at a joint between a first air duct, which extends in one direction, and a second air duct, that extends in a second different direction, to redirect air flowing in the first air duct into the second air duct and to reduce low frequency high volume noise.