Acoustic Panel for Open Rotor Noise Attenuation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Open rotor aircraft propulsion systems generate significant noise due to the absence of a nacelle or shroud, necessitating alternative noise attenuation methods.
Innovation Solution
The integration of acoustic panels, including a porous core between perforated exterior and interior sheets, positioned axially adjacent to the open rotors, which also serve as a shield to prevent blade or fragment penetration, and can extend forward or aft of the rotors to attenuate noise effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If acoustic panels are integrated into the fuselage to attenuate noise from open rotors, then noise transmission into the cabin is reduced, but the device complexity increases
Solution Approach 1:
The acoustic panel is merged with the fuselage structure, combining the noise attenuation function with the existing airframe. The panel is positioned axially adjacent to the open rotor and integrated into the fuselage body, allowing noise reduction without requiring a separate standalone acoustic system.
Solution Approach 2:
The acoustic panel serves multiple functions: it attenuates noise from open rotors, acts as a shield against blade or fragment penetration, and integrates with the fuselage structure. This multi-functionality reduces the need for additional separate systems.
2Object-affected harmful factors
If acoustic panels with porous cores and perforated sheets are used, then noise attenuation effectiveness is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The acoustic panel utilizes a porous core material that is effective at attenuating noise across a range of frequencies. The porous structure provides acoustic damping while maintaining manufacturability, as it can be produced through standard composite material fabrication processes.
Solution Approach 2:
The acoustic panel is constructed as a composite structure combining a porous core with perforated exterior and interior sheets. This composite design achieves effective noise attenuation while allowing for standard manufacturing techniques, balancing performance with manufacturability.
3Object-affected harmful factors
If the acoustic panel extends forward or aft of the open rotor, then noise attenuation coverage is improved, but the area of the acoustic panel increases
Solution Approach 1:
The acoustic panel is positioned axially adjacent to the open rotor, extending forward or aft as needed to cover the specific noise generation zones. This localized positioning achieves effective noise attenuation coverage without requiring the panel to cover the entire fuselage, optimizing the balance between coverage and area.
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 acoustic panels effectively reduce noise generated by the open rotors, providing a vibration and sound isolator structure that stiffens the fuselage and minimizes noise transmission into the cabin while preventing blade or fragment penetration.
Implementation Method 1
The acoustic panel may include a porous core connected between a perforated exterior sheet and an interior sheet
Data Source
AI summary
An aircraft includes a fuselage, an aircraft propulsion system including an open rotor, and a pylon mounting the propulsion system to the fuselage. The fuselage includes an acoustic panel configured to attenuate noise generated by the open rotor.