Hidden Blocker Doors in Aircraft Thrust Reverser
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Solution Overview
Problem
Existing thrust reverser systems for aircraft propulsion systems have flow obstructions and inefficiencies due to multiple components obstructing airflow, even when stowed, which disrupts boundary layer air flow and increases drag.
Innovation Solution
The proposed thrust reverser system includes a translating sleeve with a cascade structure, blocker doors, and linkages that are housed within cavities when stowed, allowing for axial translation and radial inward movement into the bypass gas path during deployment, minimizing flow obstructions and optimizing airflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thrust reverser components (blocker doors, linkages, cascade structure) are exposed in the bypass gas path, then reverse thrust function is achieved, but airflow disruptions and drag increase during stowed position
Solution Approach 1:
The blocker doors, linkages, and cascade structure are extracted from the bypass gas path during normal operation by positioning them within the forward cavity. Only the essential cascade structure remains exposed at the rear, while the blocker doors and linkages are completely retracted, eliminating flow obstructions and boundary layer disruptions.
Solution Approach 2:
The thrust reverser components are nested within the forward cavity when stowed. The blocker doors are positioned within the cavity, with linkages folded or retracted alongside the cascade structure, creating a compact nested arrangement that eliminates external obstructions to airflow.
2Reliability
If blocker doors are positioned radially inward during deployment, then reverse thrust effectiveness is improved, but device complexity increases
Solution Approach 1:
The blocker doors transition from a static radial position to a dynamic deployment mechanism. The doors are hinged at their aft ends and can pivot between a stowed position (aligned with the bypass duct wall) and a deployed position (radially inward blocking the gas path), with the linkage providing controlled motion during transition.
Solution Approach 2:
The blocker door assembly is segmented into multiple independent doors that can be actuated separately or in groups. Each blocker door is a discrete component hinged to the door carrier, allowing incremental deployment and simplified control of the reverse thrust function.
3Object-affected harmful factors
If thrust reverser components are completely retracted into cavities, then airflow is optimized, but accessibility for maintenance decreases
Solution Approach 1:
The thrust reverser system is divided into separable components (blocker doors, linkages, cascade structure) that can be independently accessed. The blocker doors are hinged to the door carrier, allowing them to be detached or swung open for maintenance without requiring complete disassembly of the nacelle structure.
Solution Approach 2:
The blocker doors are designed to be pre-positioned in accessible locations within the forward cavity, with hinges and mounting points arranged to facilitate easy removal or inspection. The linkage connections are designed for quick disconnect or manual manipulation during maintenance operations.
Data Source
AI summary
An assembly is provided for an aircraft propulsion system with an axial centerline. This assembly includes a nacelle structure and a thrust reverser system. The nacelle structure includes a fan cowl, where a forward cavity extends axially into the nacelle structure from an aft end of the fan cowl. The thrust reverser system includes a sleeve, a cascade structure, a blocker door and a linkage. The sleeve is configured to translate axially along the centerline and relative to the nacelle structure between a forward stowed position and an aft deployed position. The cascade structure, the blocker door and the linkage are at least partially within the forward cavity when the sleeve is in the forward stowed position. The cascade structure is fixedly attached to the sleeve. The linkage extends between and is pivotally attached to the cascade structure and the blocker door.