Jet Engine Nacelle Half-Shell Deformation Control
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Solution Overview
Problem
Conventional turbojet engine nacelles deform excessively when opened for maintenance, especially under wind conditions, due to the position of jacks and reaction forces, leading to interference with other nacelle parts and requiring long guide elements that necessitate structural modifications.
Innovation Solution
The nacelle design incorporates a second follower element angularly offset from the first, which bears against a second guide element, allowing shorter guide elements and reducing overall space usage, with the follower and guide elements only active during a limited angular travel to minimize deformation and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a single follower element is used to limit half-shell deformation, then the deformation is controlled, but the guide element becomes very long requiring structural modifications
Solution Approach 1:
The single guide element is divided into two separate guide elements (first guide element and second guide element), each paired with its own follower element. This segmentation allows each guide element to be shorter and positioned at different angular locations, eliminating the need for a single long guide element while maintaining deformation control through distributed guidance points.
2Ease of operation
If the half-shells are deployed for maintenance access, then engine access is improved, but the half-shells deform excessively under wind and reaction forces
Solution Approach 1:
The follower elements act as intermediary components between the half-shells and the guide elements. These followers engage with the guide elements during deployment to actively control and limit the deformation caused by wind and jack reaction forces, enabling maintenance access while preventing excessive deformation through continuous mechanical guidance.
3Adaptability or versatility
If the guide element is made longer to accompany the follower element's movement, then the follower can limit deformation over larger angular travel, but the space required increases significantly
Solution Approach 1:
The guidance function is segmented into two independent follower-guide pairs positioned at different angular locations. Each pair covers a limited angular range, and together they provide comprehensive coverage for the half-shell deployment motion. This segmentation reduces the length of each individual guide element while maintaining overall adaptability through the combined action of both pairs.
Data Source
AI summary
The invention relates to a jet engine nacelle intended to equip an aircraft, comprising a forward air inlet section, a mid-section intended to surround a fan of the jet engine, and an aft section formed from at least first and second hath-shells rotatably mounted about an axis such that they can each be deployed between a working position in which the half-shells are drawn towards one another and a maintenance position in which the half-shells are spaced apart, at least the first half-shell (11) being equipped with a first follower element (19) in a region situated at a distance from the axis of rotation, the nacelle being equipped with a first fixed guide element (28), the first follower element (19) being designed to bear against a first guide element (28) which is fixed with respect to the jet engine during the rotation of the first half-shell (11). The first half-shell (11) is equipped with a second follower element (20), offset angularly from the first follower element (19) with respect to the axis of rotation of the first half-shell (11), designed to bear against a second guide element (29) during the rotation of the first half-shell (11).