Offset Nacelle Thrust Reverser Cascade Design
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Solution Overview
Problem
The installation of thrust reverser devices on aircraft nacelles with low ground clearance and reduced dimensions is complicated due to height constraints, leading to increased manufacturing and maintenance costs due to the need for non-interchangeable diversion cascades with varying radii, which are specific to different areas of the nacelle.
Innovation Solution
The design allows for interchangeable diversion cascades on the entire periphery of the nacelle by offsetting the connection radii of the cascades, maintaining a constant radial distance relative to their centers, enabling identical cascades to be used across the periphery while maintaining low ground clearance and reduced nacelle dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the nacelle dimensions are reduced to accommodate low ground clearance, then the ground clearance constraint is satisfied, but the installation of thrust reverser devices becomes complicated requiring non-interchangeable diversion cascades
Solution Approach 1:
The patent applies universality by designing a single standardized diversion cascade that can be used across the entire periphery of the nacelle, replacing the previous need for multiple specialized cascades with different radii. This universal cascade design simplifies manufacturing and maintenance while accommodating the reduced nacelle dimensions through optimized geometric parameters.
2Volume of moving object
If different radii are used for diversion cascades in different areas of the nacelle, then the thrust reverser can be installed on reduced dimension nacelles, but the number of different cascade types increases leading to higher manufacturing and maintenance costs
Solution Approach 1:
The patent implements a universal diversion cascade design that eliminates the need for multiple cascade types with different radii. The standardized cascade can be installed at any position around the nacelle periphery, reducing the device complexity from multiple specialized components to a single reusable component type.
Solution Approach 2:
The patent applies parameter changes by optimizing the geometric parameters of the diversion cascade, specifically adjusting the radius and positioning to work with reduced nacelle dimensions. This allows the same cascade design to accommodate different installation locations without requiring multiple variants.
3Adaptability or versatility
If the cowl is made movable to enable thrust reversal, then the thrust reverser function is achieved, but the device complexity increases
Solution Approach 1:
The patent applies dynamics by making the cowl movable between different positions (retracted and deployed) to enable thrust reversal functionality. The cowl can slide along the longitudinal axis of the nacelle, transitioning from a position that allows normal engine operation to a position that redirects exhaust flow for thrust reversal, providing adaptability while managing complexity through a straightforward sliding mechanism.
Data Source
AI summary
A nacelle includes an outer structure provided with a thrust reverser and a front frame, a movable cowl, and an inner structure covering a downstream section of a turbojet engine. The outer structure and the inner structure define a flow stream of an air flow. In particular, the connection of the front frame and diversion cascade of the thrust reverser which is mounted on a reduced transverse section area of the movable cowl is centered on an axis offset relative to an axis on which the connection of the front frame and the diversion cascade mounted on the remainder of the periphery of the movable cowl is centered.