Aircraft Thrust Reverser Front Frame and Deflection Grid Assembly
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Solution Overview
Problem
The existing thrust reversal systems in aircraft turbojet engines require complex and costly manufacturing processes due to the over-length of the front frame, which complicates the attachment of deflection grids and affects aerodynamic performance.
Innovation Solution
An annular assembly comprising a front frame and deflection grids with a grid extension that allows attachment, maintaining aerodynamic performance by ensuring the axial distance between the first upstream blading and the overlap area is greater than or equal to the average height of the deflection grid, enabling simpler and more economical manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the front frame is made with over-length to accommodate deflection grid attachment, then the deflection grid can be attached to the front frame, but the manufacturing complexity and cost increase
Solution Approach 1:
The deflection grid is divided into two functional segments: a grid extension portion that attaches to the front frame, and a main grid portion that performs the deflection function. This segmentation allows the attachment function to be separated from the aerodynamic function, enabling simpler front frame manufacturing while maintaining grid attachment capability.
Solution Approach 2:
The grid extension acts as an intermediary element between the front frame and the main deflection grid. It provides a simplified attachment interface to the front frame while connecting to the main grid, thereby reducing the complexity requirements of the front frame itself.
2Device complexity
If the front frame dimensions are reduced for simpler manufacturing, then manufacturing complexity decreases, but the attachment of deflection grids becomes difficult
Solution Approach 1:
By segmenting the deflection grid into an extension portion and main portion, the attachment function is concentrated in the extension portion, which can be easily attached to a simplified front frame. The main grid portion then attaches to the extension, separating the attachment complexity from the aerodynamic structure.
Solution Approach 2:
The grid extension extends in the axial dimension to provide attachment surface area to the front frame. This dimensional extension allows the simplified front frame to accommodate the attachment requirements without increasing its overall complexity or requiring additional length.
3Ease of manufacture
If common attachment means are used for deflection grid, edge, and frame, then manufacturing cost decreases, but attachment precision must be maintained
Solution Approach 1:
The grid extension is designed with universal attachment features that can interface with standard attachment means used for both the front frame and the deflection edge. This multi-functionality allows the same attachment system to be used across multiple components, reducing cost while maintaining precision through standardized interfaces.
Data Source
AI summary
The invention relates to an assembly (601) which comprises a front frame (602) of a thrust reverser structure of an aircraft nacelle and at least one cascade (603). The assembly is characterized in that, when the cascade is fixed to the frame, the axial distance (L) that separates the first blading (605) upstream of the cascade from a covering area (606) between the extension of the cascade and the front frame is greater than or equal to once the mean height (h) of the cascade.