Nacelle Thrust-Reversing Door Anti-Vibration Chock Mechanism
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Solution Overview
Problem
Dual flow jet engine thrust-reversing systems experience vibrations and noise when outer doors are in stowed position, which can lead to undesirable noise generation during high-pressure conditions.
Innovation Solution
Incorporation of an anti-vibration system for each outer door, comprising a chock and a finger configured to engage and disengage as the frame translates between advanced and retracted positions, ensuring the door remains locked in stowed position and reducing vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the outer doors are made mobile between stowed and deployed positions, then the thrust-reversing capability is improved, but vibrations and noise are generated during high-pressure conditions
Solution Approach 1:
The anti-vibration system is activated before the doors are deployed, locking the doors in their stowed position to prevent vibrations from occurring during high-pressure conditions. This preliminary locking action eliminates the harmful vibrations and noise before they can be generated.
Solution Approach 2:
The anti-vibration system acts as an intermediary mechanism between the mobile door assembly and the fixed structure. It provides a controlled connection that allows the doors to remain stationary and vibration-free while still enabling their mobility when needed for thrust reversal.
2Object-generated harmful factors
If the anti-vibration system locks the door in stowed position, then vibrations are reduced, but the door mobility is restricted
Solution Approach 1:
The anti-vibration system transitions from a static locking mechanism to a dynamic system that adapts its state. It locks the door in stowed position during normal operation to eliminate vibrations, then releases to allow door mobility when thrust reversal is required, providing the optimal characteristic at each operational phase.
Solution Approach 2:
The system changes its mechanical state parameter from locked to unlocked based on operational requirements. During normal flight, the locking parameter is activated to prevent vibrations; during thrust reversal, the locking parameter is deactivated to enable door movement, thus optimizing performance across different operational modes.
Data Source
AI summary
A nacelle having a window open between a secondary jet and the outside of the nacelle and comprising a fixed structure and a thrust-reversing system having a frame and outer doors articulated on the frame. The frame is translationally mobile on the fixed structure between an advanced position and a retracted position. Each outer door is mobile between a stowed position and a deployed position. The nacelle comprises at least one anti-vibration system which comprises a chock fixed to the fixed structure and having a hole, and a finger fixed to the outer door. The finger and the hole are configured so that the finger lodges in the hole when the frame is in advanced position. Such a nacelle makes it possible to limit the vibrations of the outer doors when they are in stowed position and before the mobile frame begins to be displaced to the retracted position.