Modular Air Inlet Lip for Turbine Nacelle Acoustic Integration
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Solution Overview
Problem
The existing manufacturing processes for aircraft turbomachine air inlet lips with integrated acoustic devices are complex, costly, and prone to mechanical deformation, requiring brazing that compromises mechanical strength and increases mass, while also being challenging due to geometric tolerances and the need for precise machining of acoustic orifices.
Innovation Solution
A modular design for the air inlet lip, comprising two assembled modules with a front and rear skin, where the acoustic device is sandwiched radially, allowing for simpler assembly and maintenance, preservation of mechanical characteristics, and the formation of blow openings during assembly to facilitate defrosting without complex machining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If brazing is used to fix the rear skin to the inner wall, then the acoustic device can be integrated, but the mechanical characteristics of the inner wall are reduced and mass increases
Solution Approach 1:
The lip is divided into two separate modules: a first module comprising the outer wall and upstream portion of the inner wall, and a second module comprising the acoustic device and downstream portion of the inner wall. These modules are assembled together without brazing, preserving the mechanical characteristics of the inner wall while enabling acoustic device integration.
2Ease of manufacture
If brazing is used to fix the rear skin to the inner wall, then the acoustic device can be integrated, but the lip mass increases
Solution Approach 1:
The lip is divided into two separate modules that are assembled together without requiring increased thickness, thereby avoiding the mass increase that would result from thickening the inner wall to compensate for brazing damage.
3Ease of manufacture
If brazing is used to fix the rear skin to the inner wall, then the acoustic device can be integrated, but the inner wall is likely to deform during cooling
Solution Approach 1:
The lip is divided into two separate modules that are assembled together without brazing, eliminating the thermal deformation risk associated with brazing cooling while maintaining acoustic device integration capability.
4Ease of manufacture
If brazing is used to fix the rear skin to the inner wall, then the acoustic device can be integrated, but complex tooling is required to hold the modules together
Solution Approach 1:
The lip is divided into two separate modules that are assembled together without requiring complex brazing tooling. The assembly process is simplified by eliminating the need for specialized brazing equipment and fixtures while maintaining acoustic device integration.
5Manufacturing precision
If machining of acoustic orifices is performed, then precise alignment with acoustic material cells is achieved, but the process is complex and time-consuming
Solution Approach 1:
The lip is divided into two separate modules where the acoustic device is pre-assembled with its orifices aligned to the acoustic material cells before integration. This modular approach eliminates the need for complex post-assembly machining operations while maintaining precise alignment.
6Ease of manufacture
If the lip is heated in a brazing furnace, then the acoustic device can be fixed to the inner wall, but the outer wall is likely to collapse during heating
Solution Approach 1:
The lip is divided into two separate modules that are assembled together without subjecting the outer wall to high-temperature brazing. This eliminates the risk of outer wall collapse during heating while enabling acoustic device integration through alternative assembly methods.
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 modular design simplifies manufacturing, reduces costs, minimizes defects, and allows for easier replacement of acoustic modules, while maintaining mechanical integrity and avoiding deformation, and enables efficient defrosting without compromising mechanical strength.
Implementation Method 1
an acoustic device to limit these nuisances
Implementation Method 2
a hot air injector in the annular cavity and to form blowing openings in the inner wall, preferably upstream of the acoustic device in order to heat the inner wall
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to an air intake lip (2a) of an aircraft turbomachine nacelle extending along an axis X, in which an air flow circulates from upstream to downstream, the lip (2a) extending annularly about the X-axis and having an inner wall (21) facing the X-axis and an outer wall (22) which is opposite the inner wall (21), the inner wall (21) and the outer wall (22) being connected by an upstream wall (23) so as to delimit an annular cavity (20), the lip (2a) comprising an annular acoustic device (50) mounted in the annular cavity (20). The lip (2a) has a first module (M1), comprising the outer wall (22), the wall (23) and a front wall (24) forming an upstream portion of the inner wall (21), and a second module (M2), comprising the acoustic device (50) and a front skin (51) forming a downstream portion of the inner wall (21), the first module (M1) and the second module (M2) being secured together so that the front wall (24) and the front skin (51) together form the inner wall (21) of the lip (2a).