Deployable Membrane Thrust Reverser for Lower Drag Counter-Thrust
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Solution Overview
Problem
Existing thrust reversers with cascade vanes in aircraft propulsion units face issues of increased mass, drag, and specific fuel consumption due to the need for longer vanes to achieve counter-thrust performance, which also cause aerodynamic disturbances and limit the installation of acoustic panels.
Innovation Solution
Replace cascade vanes with deployable deflecting membranes that extend radially outward in a deployed configuration, diverting the secondary flow to enhance counter-thrust performance without increasing the axial length of the reverser, thus reducing mass and drag.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If cascade vanes are used to generate counter-thrust, then counter-thrust performance is achieved, but the axial length of the reverser increases leading to greater mass and drag
Solution Approach 1:
The patent transitions from axial extension (cascade vanes extending axially to provide counter-thrust) to radial extension (deflecting membrane extending radially outward). By changing the dimension in which the flow deflection is achieved, the counter-thrust function is maintained while reducing the axial length requirement.
Solution Approach 2:
The patent employs a flexible deflecting membrane instead of rigid cascade vanes. This thin film structure can be deployed radially outward to deflect flow and generate counter-thrust, providing the same functional capability with significantly reduced axial dimensions and mass.
2Power
If cascade vanes are extended to improve counter-thrust, then counter-thrust performance increases, but mass and drag increase
Solution Approach 1:
The deflecting membrane is a thin flexible structure that replaces heavy rigid cascade vanes. This thin film provides the necessary flow deflection and counter-thrust generation with minimal mass, directly reducing the reverser mass while maintaining or improving counter-thrust performance.
Solution Approach 2:
The deflecting membrane is a movable component that can be deployed and retracted dynamically. When deployed, it extends radially outward to deflect flow and generate counter-thrust. When retracted, it minimizes interference with the jet flow. This dynamic capability allows optimal performance with minimal mass compared to static rigid vanes.
3Reliability
If sealing flaps are used to seal the secondary flow duct, then flow containment is improved, but aerodynamic disturbances increase and acoustic panel installation is limited
Solution Approach 1:
The patent replaces rigid sealing flaps with a flexible deflecting membrane. This thin film structure provides smooth flow containment without creating the aerodynamic disturbances associated with rigid flaps. The membrane's flexibility allows it to conform to flow patterns, reducing turbulence and aerodynamic interference.
Solution Approach 2:
The deflecting membrane is a dynamic component that can be deployed or retracted based on operational requirements. When deployed, it provides smooth flow containment and counter-thrust generation. When retracted, it eliminates interference with the jet flow and acoustic panel installation. This dynamic capability resolves the contradiction between flow containment and aerodynamic disturbances.
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 use of deployable deflecting membranes improves counter-thrust performance, reduces the reverser's axial dimension, and enhances the overall propulsion unit's efficiency by minimizing drag and specific fuel consumption while allowing more aerodynamic design freedom.
Implementation Method 1
at least one deflecting membrane (32) designed to divert said at least part of the secondary flow escaping from the radial extraction opening
Implementation Method 2
in this deployed configuration said at least one deflecting membrane extends radially outwards beyond the movable reverser cowl
Data Source
AI summary
A thrust reverser (30) for an aircraft propulsion unit, the reverser comprising a stationary structure (31) and a movable structure (29) comprising at least one movable reverser cover (33) delimiting the secondary flow path (21B), the movable structure being translatable with respect to the stationary structure between an advanced direct-thrust position and a retracted thrust-reversal position in which the movable structure (29) and the stationary structure (31) axially define therebetween, on the secondary flow path, a radial extraction opening (56) for at least one portion (20B′) of the secondary flow. The thrust reverser also comprises at least one deployable deflecting membrane (32, 32′) which is designed to deflect the at least one portion (20B′) of the secondary flow forwards. Moreover, in the deployed configuration, the membrane (32, 32′) extends radially outwards beyond the movable reverser cover (33).