Thrust Reverser Cascade System Eliminates Blocker Doors
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Solution Overview
Problem
Conventional thrust reverser systems in high-bypass turbofan engines require blocker doors that increase aerodynamic drag, reduce engine performance, and create noise attenuation issues due to their design, which compromises the nacelle diameter and fan duct area.
Innovation Solution
A thrust reverser system that eliminates blocker doors by using a translating cowl and pivotally-translatably coupled cascade system, which moves from a stowed to a deployed position without blocking air flow, allowing bypass air to be diverted through the bypass duct, thereby reducing aerodynamic drag and enabling uninterrupted acoustic treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blocker doors are used in conventional thrust reverser systems, then thrust reversal function is achieved, but aerodynamic drag increases and engine performance decreases
Solution Approach 1:
The patent removes the blocker doors from the thrust reverser system entirely. Instead of using doors to block airflow, the invention uses a translating cowl that moves to open a passage, allowing airflow to be diverted through the bypass duct without obstruction. This extraction of the harmful component (blocker doors) directly reduces aerodynamic drag while maintaining the thrust reversal function through alternative means (translating cowl and cascade system).
Solution Approach 2:
The patent employs a translating cowl that can move dynamically between positions. The cowl translates in the axial direction to open a passage for airflow, and the cascade system pivots and translates to divert airflow. This dynamic operation eliminates the need for static blocker doors, reducing aerodynamic drag during operation while maintaining thrust reversal capability when needed.
2Reliability
If blocker doors are used in conventional thrust reverser systems, then thrust reversal function is achieved, but nacelle diameter and fan duct area are compromised
Solution Approach 1:
By removing the blocker doors that occupied space within the nacelle and fan duct, the invention frees up the nacelle diameter and fan duct area. The translating cowl and cascade system achieve thrust reversal without requiring the additional space that blocker doors would occupy, thus preserving the original dimensional characteristics of the nacelle and fan duct.
Solution Approach 2:
Instead of using blocker doors that extend radially inward from the fan duct outer surface, the invention uses a translating cowl that moves in the axial dimension. The cascade system pivots and translates to create the blocking effect in a different spatial arrangement, eliminating the need for radial space occupation and preserving the nacelle diameter.
3Reliability
If blocker doors are used in conventional thrust reverser systems, then thrust reversal function is achieved, but acoustic treatment is disrupted and noise attenuation is reduced
Solution Approach 1:
The patent removes the blocker doors that disrupted acoustic treatment continuity. By eliminating these doors, the acoustic treatment can be applied continuously without interruptions or gaps, improving noise attenuation while maintaining the thrust reversal function through the translating cowl and cascade system.
Solution Approach 2:
The invention merges the thrust reversal function with the acoustic treatment system by eliminating the blocker doors that created discontinuities. The translating cowl and cascade system provide thrust reversal while allowing uninterrupted acoustic treatment coverage, combining both functions without the harmful effects of door-induced acoustic disruptions.
4Reliability
If blocker doors are used in conventional thrust reverser systems, then thrust reversal function is achieved, but device complexity increases
Solution Approach 1:
The patent removes the blocker doors and their associated mounting mechanisms, linkages, and control systems from the thrust reverser assembly. This extraction simplifies the overall device complexity by eliminating multiple components while maintaining the essential thrust reversal function through the translating cowl and cascade system.
Solution Approach 2:
The translating cowl and cascade system serve multiple functions: they provide thrust reversal, manage airflow diversion, and eliminate the need for separate blocker door mechanisms. This multi-functionality reduces device complexity by consolidating what would otherwise require separate components into a unified system.
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 significantly reduces aerodynamic drag, enhances acoustic efficiency, and allows for a smaller nacelle diameter and weight reduction by eliminating the need for blocker doors, while maintaining effective thrust reversal.
Implementation Method 1
the cascade system having a fore end and an oppositely-disposed aft end; guide connections coupled to the fixed structure of the nacelle and slidably connected to the fore end of the cascade system and adapted to axially guide the fore end as the cascade system translates in the aft direction with the translating cowl and thereafter as the aft end pivots about the fore end
Implementation Method 2
the transcowl 34A is adapted to be translated aft to expose the cascade 34B and deploy the blocker doors 34C into the duct 30
Implementation Method 3
The blocker doors 34C are adapted to be pivotally deployed from their stowed position to a deployed position, in which the aft end of each blocker door 34C is pivoted into engagement with the core cowl 36
Data Source
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AI summary
A thrust reverser system and operation suitable for high-bypass turbofan engines. The thrust reverser system includes a cascade system adapted to be translated with a translating cowl in an aft direction of an engine to expose a circumferential opening. The cascade system is deployed from a stowed position as the translating cowl and the cascade system are translated in the aft direction. During deployment of the cascade system, a fore end thereof translates in the aft direction and an aft end thereof initially translates in the aft direction and then subsequently rotates about the fore end so that further translation of the cascade segment in the aft direction causes the cascade segment to move to a deployed position and divert bypass air within a bypass duct of the engine through the circumferential opening.