Rotary Thrust-Reverser Blades for Lighter Turbofan Secondary Flow Blocking

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Solution Overview

Problem

Existing turbofan engines rely on heavy reversing doors and their drive mechanisms to deflect secondary flow for counter-thrust, which are undesirable due to weight and complexity, and there is a need for a lighter and more efficient mechanism.

Innovation Solution

The use of rotatably mounted blades that can close off the secondary flow path, replacing traditional reversing doors with a simplified maneuvering system, allowing for the deflection of secondary flow towards a window in the nacelle to produce counter-thrust.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If traditional reversing doors and their drive mechanisms are used to deflect secondary flow, then counter-thrust can be produced, but the weight and device complexity increase

Engineering Contradiction:

Improvecounter-thrustVSAvoidweight of reversing mechanism

Core Design Contradiction:

ForceVSWeight of moving object

Solution Approach 1:

The reversing door is divided into multiple independent rotatable blades that can operate separately. Each blade is mounted on a common rotating assembly, allowing the system to achieve the same flow deflection function with lighter, distributed components rather than a single heavy door structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of using a traditional reversing door that pivots on a fixed axis, the invention inverts the approach by using multiple blades that rotate on a common rotating assembly. This inversion allows the entire blade assembly to rotate, providing flow deflection with reduced mechanical complexity and weight.

Inventive Principle:

Principle #13The other way round (Inversion)

2Force

If traditional reversing doors and their drive mechanisms are used to deflect secondary flow, then counter-thrust can be produced, but the device complexity increases

Engineering Contradiction:

Improvecounter-thrustVSAvoidcomplexity of drive mechanism

Core Design Contradiction:

ForceVSDevice complexity

Solution Approach 1:

Multiple individual blade control mechanisms are merged into a single rotating assembly. By combining the control of multiple blades into one unified rotation system, the invention reduces the number of separate actuators and control mechanisms needed, thereby simplifying the overall device complexity while maintaining the ability to deflect secondary flow for counter-thrust.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The rotating assembly serves multiple functions: it simultaneously controls the position of multiple blades, deflects secondary flow, and produces counter-thrust. This multi-functionality reduces the need for separate dedicated mechanisms for each function, thereby reducing overall device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Weight of moving object

If rotatably mounted blades are used to close off secondary flow path, then weight is reduced, but the maneuvering system complexity may increase

Engineering Contradiction:

Improveweight of reversing mechanismVSAvoidcomplexity of maneuvering system

Core Design Contradiction:

Weight of moving objectVSDevice complexity

Solution Approach 1:

The maneuvering system merges the control of multiple lightweight blades into a single rotating assembly mechanism. This consolidation reduces the total number of separate actuators and control systems needed, thereby offsetting the complexity that might arise from using multiple rotating blades while maintaining the weight advantage of the lighter blade structure.

Inventive Principle:

Principle #5Merging (Combining)

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 solution reduces weight and complexity by enabling efficient deflection of secondary flow, enhancing the turbofan engine's performance while minimizing the need for additional actuators, resulting in a lighter and more efficient counter-thrust mechanism.

Implementation Method 1

a series of blades (250) which are mounted so as to be able to rotate in order to close off the stream (204) of secondary flow

Methodology Applied

Scientific EffectFluid flow deflection:

Data Source

PatentEP3686418B1Dual-flow turbojet engine comprising a series of rotary strips for blocking the secondary flow stream

Publication Date: 2021.12.01 AIRBUS OPERATIONS (SAS)

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Figure 5~6

AI summary

The invention relates to a turbofan engine (100) with a nacelle (102) comprising a slide (218) movable in translation between an advanced position and a rearward position to open a window between a duct and the outside, a plurality of blades (250), each movable in rotation on the slide (218) between a retracted position and a deployed position, and a maneuvering system (400) moving each blade (250) and comprising for each blade (250), a shaft (402) movable in rotation on the slide (218) and on which the blade (250) is fixed, and a toothed sector (406) fixed on the shaft (402), and a toothed arc (408) movable in rotation on the slide (218) about a longitudinal axis (X), where the teeth of the toothed arc (408) mesh with the teeth of each toothed sector (406), a cam (504) attached to the toothed arc (408), and a groove (502) attached to a fixed structure (206) in which the cam (504) is housed and where, during the movement of the slider (218),The cam (504) follows the groove (502) and rotates the toothed arc (408). The use of rotating blades on the slide and the simplified operating system allows for a lighter assembly compared to the use of prior art reversing gates.