Fixed-Cascade Thrust Reverser Sealing Membrane for Low Drag
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Solution Overview
Problem
Existing thrust reversers in aircraft propulsion units suffer from aerodynamic disturbances and acoustic issues due to the presence of sealing flaps, which also limit the installation of acoustic panels, and existing sealing membranes have implementation and reliability challenges.
Innovation Solution
A thrust reverser design incorporating sealing membranes connected by hooking means to the rear cascade support frame and the radially inner wall of the secondary flow path, allowing for smooth deployment and improved aerodynamic and acoustic performance by eliminating geometric singularities in the secondary flow path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sealing flaps are used to seal the secondary flow path, then the secondary flow is diverted towards the cascade vanes, but aerodynamic disturbances are introduced and acoustic panel installation is limited
Solution Approach 1:
The patent replaces rigid sealing flaps with a flexible sealing membrane that seals the secondary flow path. The membrane is anchored at its ends to the fixed structure and movable structure, allowing it to flex and seal effectively without introducing aerodynamic disturbances or limiting acoustic panel installation.
Solution Approach 2:
The invention extracts and removes the harmful sealing flaps from the system, replacing them with a membrane that achieves sealing without the adverse effects of traditional flaps on aerodynamic performance and acoustic panel installation.
2Reliability
If sealing flaps are installed in recesses of the radially inner wall, then sealing is achieved, but the acoustic surface is limited and drag increases
Solution Approach 1:
The sealing membrane spans across the opening without requiring recesses in the radially inner wall, maintaining a smooth acoustic surface that reduces aerodynamic drag while effectively sealing the secondary flow path.
Solution Approach 2:
The membrane is positioned in a different spatial arrangement compared to traditional flaps, extending between the fixed and movable structures rather than being recessed into the wall, thereby preserving the external acoustic surface.
3Reliability
If traditional sealing membranes are used, then sealing is provided, but deployment reliability and ease of implementation are insufficient
Solution Approach 1:
The sealing membrane is pre-positioned and anchored at both ends before operation. The first end is anchored to the fixed structure and the second end to the movable structure, ensuring reliable deployment without requiring complex mechanisms during operation.
Solution Approach 2:
The membrane automatically seals the secondary flow path through its elastic properties when the movable structure moves, without requiring additional actuators or complex deployment mechanisms, thereby improving ease of implementation and reliability.
Data Source
AI summary
A thrust reverser for an aircraft propulsion assembly, including a fixed structure equipped with at least one cascade as well as a radially inner delimiting wall of a secondary vein, and a movable structure including at least one reverser cowling, the cascade being arranged, in the forward direct thrust position, in a housing of the reverser cowling, and, in the retracted thrust reversal position, the wall reveals a passage opening of the secondary vein towards the cascade, the thrust reverser also including at least one sealing membrane designed to deflect at least one portion of the secondary flow. A hook is provided for securing the membrane to a rear cascade support frame, and to the radially inner delimiting wall of the secondary vein.