Thrust Reverser Blocker Door Stowing Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional thrust reversers in high-bypass turbofan engines suffer from increased aerodynamic drag, reduced aerodynamic performance, and noise attenuation due to blocker doors and link arms that protrude into the fan duct flow path, causing surface interruptions and exposure to damage during normal operation.
Innovation Solution
A thrust reverser assembly with blocker doors that can be completely stowed within the nacelle, using a translating cowl and fixed structure to deploy the doors into the bypass duct, eliminating surface interruptions and reducing exposure to damage, while maintaining acoustic treatment and reducing design complexity and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blocker doors and link arms are used in conventional thrust reversers, then thrust reversal function is achieved, but aerodynamic drag increases and flow perturbations occur
Solution Approach 1:
The blocker doors are extracted from the external flow path and stowed within the nacelle cavity when not in use. Only the necessary portions protrude into the bypass duct during thrust reversal operation, minimizing surface interruptions and aerodynamic drag during normal flight conditions.
Solution Approach 2:
The blocker doors are designed to be dynamically deployable rather than permanently fixed. They pivot between stowed and deployed positions based on operational needs, allowing the system to adapt its configuration to optimize aerodynamic performance during different flight phases.
2Reliability
If blocker doors protrude into the fan duct flow path, then thrust reversal is enabled, but surface interruptions increase causing reduced aerodynamic performance
Solution Approach 1:
The thrust reverser system is segmented into multiple independent blocker doors that can be individually deployed or stowed. This segmentation allows selective positioning of only the necessary components into the flow path, minimizing surface interruptions compared to a fully exposed conventional design.
3Ease of operation
If blocker doors are exposed during normal operation, then thrust reversal function is accessible, but doors are exposed to damage and wear-inducing conditions
Solution Approach 1:
The blocker doors are extracted from the exposed external environment and repositioned within the protected nacelle cavity during normal operation. This extraction shields them from damage-prone conditions while maintaining quick accessibility when thrust reversal is needed.
Solution Approach 2:
Instead of having the blocker doors permanently exposed and protected by external structures, the design inverts the arrangement by stowing them internally within the nacelle and only deploying them when needed. This internal stowing configuration naturally protects the doors from external damage sources.
4Ease of operation
If link arms are used to deploy blocker doors, then deployment mechanism is provided, but link arms protrude into flow path causing additional drag
Solution Approach 1:
The link arms are extracted from the external flow path and their deployment function is integrated into the nacelle structure. The deployment mechanism operates internally or along the nacelle contours, removing the harmful protruding link arms from the bypass duct flow path.
5Reliability
If blocker doors define portions of fan duct outer flow surfaces, then thrust reversal structure is provided, but gaps and steps increase aerodynamic drag
Solution Approach 1:
The blocker doors are extracted from the external fan duct flow surfaces and repositioned within the nacelle cavity. This extraction eliminates the gaps and steps that would occur at the interfaces between blocker doors and duct surfaces, as the doors no longer form part of the external flow path geometry.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A thrust reverser assembly (12C) and operation suitable for high-bypass turbofan engines (10). The thrust reverser assembly includes a translating cowl (34A) mounted to a nacelle (12) of an engine and adapted to translate in an aft direction of the engine. The translating cowl has a radially inner wall (46) that defines a radially outer flow surface of a bypass duct (30) of the engine. The thrust reverser assembly includes blocker doors (34C) axially guided adjacent first ends (54) thereof by a fixed structure (34B) and pivotally and slidably connected along lengths thereof to the inner wall of the translating cowl so that translation of the translating cowl in the aft direction causes each blocker door to move from a stowed position to a deployed position as a result of the blocker door sliding at its first end relative to the fixed structure and sliding along its length relative to the inner wall of the translating cowl.