Aircraft Thrust Reverser Rigid Shutter Sealing
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Solution Overview
Problem
Existing thrust reversers for dual-flow turbojet nacelles suffer from thrust losses due to whirlwind structures formed in the secondary air flow, which are difficult to manage with flexible composite materials used for shutters.
Innovation Solution
The thrust reverser design incorporates shutters with rigid walls extending to upstream, downstream, and lateral edges, and features first and second sealing elements along the lateral and downstream edges, respectively, to prevent air leaks and reduce thrust losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If flexible composite materials are used for shutters, then ease of manufacture is improved, but thrust losses due to whirlwind structures increase
Solution Approach 1:
The patent changes the material parameter from flexible composite to rigid material for the shutter walls, specifically addressing the thrust loss issue while maintaining manufacturing feasibility through the rigid structure design
Solution Approach 2:
The shutter is divided into multiple segments with rigid walls, allowing each segment to be manufactured separately and assembled, maintaining ease of manufacture while achieving the rigid structure needed to prevent whirlwind formation
2Loss of energy
If sealing elements are added along lateral edges, then energy loss is reduced, but device complexity increases
Solution Approach 1:
The sealing elements are integrated into the shutter structure itself, merging the sealing function with the shutter wall design rather than adding separate external sealing components, thus reducing device complexity while preventing energy loss
3Productivity
If rigid walls are used for shutters, then thrust reversal efficiency is improved, but manufacturing difficulty increases
Solution Approach 1:
The rigid shutter structure is segmented into multiple sections that can be manufactured separately using standard rigid material fabrication processes, then assembled together, maintaining thrust reversal efficiency while improving manufacturing ease
Solution Approach 2:
The patent employs composite construction for the rigid walls, combining materials that provide both the necessary rigidity for efficient thrust reversal and manufacturability through available fabrication techniques
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 limits air flows through interstices between shutters and the upstream hood portion, reducing energy loss and improving thrust reversal efficiency without compromising the internal aerodynamic performance of the shutters.
Implementation Method 1
first sealing elements located on the external face of the wall of each flap and/or on an external face of the fairings, these first sealing elements extending along the lateral edges of the flap and/or of the fairings so as to ensure a seal along these edges in the first position
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
The invention relates to a thrust reverser (30) for an aircraft bypass turbojet engine nacelle, this thrust reverser having a generally annular shape around an axis (A) and comprising in particular flaps (10) for deflecting the secondary flow (F11) through gratings (13), each of these flaps comprising a rigid wall (32) and sealing elements (34) located on the outer face (32b) of this wall (32), these sealing elements extending along side edges (10c, 20c) of the flap (10) so as to provide a seal along these edges in the first position.