Fan Case Thrust Reverser Cascade Helical Ribs

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Solution Overview

Problem

Conventional thrust reversers in gas turbine engines are often bulky and inefficient, leading to increased drag, pressure loss, and weight, which can limit their effectiveness in reducing landing distance and improving fuel burn performance.

Innovation Solution

A compact thrust reverser design integrated with a fan case, featuring a thrust reverser cascade section with helically arranged ribs and cascade airfoils, which redirects bypass flow through a 360-degree discharge area, utilizing a combination of actively and passively deployed doors to optimize airflow and reduce nacelle size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional thrust reversers are used, then thrust reversal function is provided, but drag, pressure loss, and weight increase

Engineering Contradiction:
Improvepressure lossVSAvoidthrust reversal effectiveness
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The thrust reverser cascade section is merged with the fan case structure, forming an integrated assembly where the cascade section forms a rearward outer wall portion of the bypass duct. This integration eliminates separate structural components, reduces overall weight, and streamlines airflow paths to reduce pressure loss while maintaining thrust reversal effectiveness.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cascade array is arranged in a three-dimensional configuration with helically arranged ribs and cascade airfoils that extend circumferentially about the engine axis. This spatial arrangement optimizes airflow redirection through a 360-degree discharge area, improving thrust reversal efficiency while compacting the overall structure to reduce drag.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Loss of energy

If conventional thrust reversers are used, then thrust reversal function is provided, but drag increases

Engineering Contradiction:
ImprovedragVSAvoidthrust reversal effectiveness
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The cascade array utilizes a three-dimensional helical arrangement of ribs and airfoils that wrap circumferentially around the engine axis, enabling airflow redirection through a 360-degree discharge area. This spatial configuration optimizes the airflow path, reducing drag while maintaining effective thrust reversal.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

By integrating the thrust reverser cascade section with the fan case, the design eliminates separate structural components and streamlines the external geometry, reducing the overall drag profile while preserving the thrust reversal function through the cascade array's airflow redirection capability.

Inventive Principle:
Principle #5Merging (Combining)

3Weight of moving object

If conventional thrust reversers are used, then thrust reversal function is provided, but weight increases

Engineering Contradiction:
Improvethrust reverser weightVSAvoidthrust reversal effectiveness
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The thrust reverser cascade section is integrated with the fan case structure, forming a unified assembly that eliminates the need for separate structural components. This merging significantly reduces the overall weight of the thrust reverser system while maintaining structural integrity and thrust reversal effectiveness through the cascade array's aerodynamic design.

Inventive Principle:
Principle #5Merging (Combining)

4Weight of stationary object

If compact thrust reverser design is used, then drag and weight are reduced, but device complexity increases

Engineering Contradiction:
Improvenacelle weightVSAvoidthrust reverser structure complexity
Core Design Contradiction:
Weight of stationary objectVSDevice complexity

Solution Approach 1:

The thrust reverser system is segmented into functional modules: the fan case, the cascade section with helically arranged ribs, the cascade array with airfoils, and the deployable doors. This segmentation allows for modular manufacturing and assembly, reducing overall structural complexity while achieving the compact design goals.

Inventive Principle:
Principle #1Segmentation

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

The solution provides a more efficient thrust reversal system with reduced drag, pressure loss, and weight, allowing for improved fuel burn performance and the ability to locate the engine closer to the aircraft wing leading edge, enhancing overall engine operation and aircraft performance.

Implementation Method 1

cascade airfoils which redirect bypass flow

Methodology Applied
Scientific EffectAerodynamic flow redirection: Aerofoil

Implementation Method 2

thrust reverser cascade section with helically arranged ribs and cascade airfoils, which redirects bypass flow through a 360-degree discharge area

Methodology Applied
Scientific EffectHelical flow pattern: Helix

Data Source

PatentEP2570641B1Fan case with thrust reverser cascade section, corresponding fan section and gas turbine engine
Publication Date: 2018.02.21 UNITED TECH CORP
  • EP2570641B1 patent drawingFigure 1
  • EP2570641B1 patent drawingFigure 2
  • EP2570641B1 patent drawingFigure 3

AI summary

A fan case (72) of a gas turbine engine (20) includes a fan blade containment section (78) defined about an engine axis (A), a thrust reverser cascade section (80) downstream of the blade containment section (78) and a Fan Exit Guide Vane section (82) downstream of the thrust reverser cascade section (80). A corresponding fan section (22) and a gas turbine engine (20) are also provided.