Self-Supporting Cascade for Thrust Reverser
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Modern thrust reverser systems for aircraft turbojet engines face challenges in minimizing aerodynamic losses and reducing the radial thickness of the rear frame, which limits the deflection efficiency of cold air flow, and existing self-supporting grid assemblies suffer from increased length leading to reduced air flow deflection effectiveness.
Innovation Solution
A self-supporting deflection grid assembly where grids are connected only in their downstream parts, minimizing the length of connection means to occupy no more than three rows of cells, maintaining an openwork surface in upstream and central parts to reduce aerodynamic losses and maintain deflection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the rear frame thickness is increased to provide inertia to the grid assembly, then the structural stability is improved, but the radial thickness of the rear frame increases, leading to increased aerodynamic losses
Solution Approach 1:
The patent removes the rear frame structure entirely and replaces it with a self-supporting grid assembly where grids are connected only in their downstream parts. This extraction of the harmful rear frame element eliminates the source of aerodynamic losses while maintaining structural stability through the self-supporting configuration of the grids themselves.
Solution Approach 2:
The grid assembly becomes self-supporting without requiring a rear frame for structural stability. The grids connect to each other in their downstream parts to form a self-stabilizing structure that maintains its configuration during operation, eliminating the need for the previously required thick rear frame.
2Stability of the object's composition
If the connection means between grids extend along the entire length of the grids, then the structural stability is improved, but the passage section loss increases and deflection efficiency decreases
Solution Approach 1:
The connection means are segmented to extend only along a limited portion (downstream part) of the grids rather than the entire length. This segmentation allows the grids to maintain structural stability through localized connections while preserving openwork surface area in upstream and central parts for efficient air flow deflection.
Solution Approach 2:
The connection means are positioned locally in the downstream part of the grids where they provide structural stability, while the upstream and central parts remain openwork to optimize air flow deflection. This local differentiation of structural vs. aerodynamic functions resolves the contradiction between stability and efficiency.
3Stability of the object's composition
If the grid length is increased to compensate for passage section loss, then the structural stability is improved, but the overall length of the grid assembly increases, reducing deflection effectiveness
Solution Approach 1:
Multiple grids are merged into a single self-supporting assembly where grids connect in their downstream parts to form an integrated structure. This merging provides structural stability across the entire assembly without requiring each individual grid to be excessively long, as the connected configuration distributes and maintains stability throughout the structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration minimizes passage section loss and grid length, enhancing the deflection of secondary flow and overall braking performance while reducing the overall cost of the assembly.
Implementation Method 1
the reverser obstructs the annular channel of the cold air flow and directs the latter towards the front of the nacelle, thereby generating a counter-thrust
Implementation Method 2
first and second connecting means formed on the respectively first and second transverse edges to connect the grid to two adjacent grids in position on the thrust reverser
Data Source
Figure 1~3
Figure 4~5
Figure 6~7
AI summary
The invention relates to a self-mounted cascade (61) for a thrust reverser of an airplane jet engine nacelle, said cascade comprising an upstream portion (612), provided with an upstream attachment means designed for attaching the cascade onto a stationary structure of the nacelle, and moreover comprising an opposite downstream portion (613) on which downstream connection means (617, 620), placed only on said downstream portion and designed to connect the cascade to at least one adjacent cascade, are provided so that two adjacent cascades are directly connected to one another only in the respective downstream portions thereof by the downstream connection means thereof. Said downstream portion corresponds to an area extending from a downstream side edge over a length less than or equal to N times the length of the last cavity located along said downstream side edge, where N is less than 3. The present invention is of use in the field of airplane jet engine nacelles.