Thrust Reverser Door Fluid Diversion System

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Solution Overview

Problem

The existing thrust reversers for turbojet engines suffer from leakage fluids flowing through the axial clearance between the door and the fixed structure, potentially contaminating sensitive areas and causing damage or fire risks due to insufficient sealing.

Innovation Solution

A fluid diverter system comprising projections or deflectors fixed to the door and the fixed structure, extending locally into the axial clearance to redirect external fluids away from sensitive areas, forming a local barrier that diverts fluids to the exterior, with specific configurations allowing for manufacturing and installation tolerances and material flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a circumferential seal is mounted on the door to prevent fluid leakage, then sealing performance is improved, but the door movement range and operational flexibility are reduced due to the seal restricting clearance

Engineering Contradiction:

Improvesealing performanceVSAvoiddoor movement range

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The sealing system is divided into two independent parts: a circumferential seal mounted on the door for radial sealing, and a separate axial seal mounted on the downstream frame for axial clearance sealing. This segmentation allows each seal to perform its specific function without interfering with door movement, as the axial seal is positioned downstream of the door's rotation path.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An intermediary axial seal is introduced between the door and the downstream frame to specifically address the axial clearance sealing problem. This intermediary element provides the necessary sealing function in the axial direction without constraining the door's rotational movement in the radial direction.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the axial clearance between the door and downstream frame is reduced to improve sealing, then fluid leakage is reduced, but manufacturing precision requirements increase and assembly difficulty increases

Engineering Contradiction:

Improvefluid containmentVSAvoidclearance control precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

An axial seal is introduced as an intermediary element between the door and downstream frame to provide the necessary fluid containment. This seal compensates for variations in axial clearance without requiring extremely tight manufacturing tolerances, as the seal itself accommodates the clearance variations while maintaining sealing effectiveness.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The sealing approach changes from relying solely on reducing the axial clearance dimension to using a sealing element that actively prevents fluid passage. The axial seal changes the parameter of fluid containment from geometric clearance-based to element-based sealing, allowing greater flexibility in clearance dimensions.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If the axial clearance is increased to ease door movement, then operational flexibility is improved, but fluid leakage increases and contamination risks increase

Engineering Contradiction:

Improvedoor movementVSAvoidfluid contamination

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The sealing function is segmented into two independent seals: the circumferential seal on the door handles radial sealing, and the axial seal on the downstream frame handles axial clearance sealing. This allows the axial clearance to be sufficiently large for easy door movement while the axial seal prevents fluid leakage through the clearance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The axial seal acts as an intermediary barrier in the axial clearance path, preventing fluids from leaking through the gap between the door and downstream frame. This intermediary element allows the clearance to remain large for operational ease while blocking the harmful fluid contamination path.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Effectively prevents external fluids from entering the clearance between the door and the fixed structure, reducing contamination risks and ensuring the integrity of the thrust reverser system during aircraft operation.

Implementation Method 1

The projection or deflector is configured for modifying the direction of flow of a stream of fluids external to the thrust reverser

Methodology Applied

Scientific EffectFluid flow redirection:

Data Source

PatentUS12258924B2Thrust reverser with door of a nacelle of a turbojet engine of an aircraft with a system for diverting fluids to the exterior

Publication Date: 2025.03.25 SAFRAN NACELLES

AI summary

A thrust reverser of a nacelle of a turbojet engine of an aircraft extending about a longitudinal axis and including a fixed structure and at least one door which is rotatable between a closed position and an open position and including a downstream frame spaced axially from a downstream end edge of the door by an axial clearance parallel to the longitudinal axis. The thrust reverser includes a system for diverting fluids to the exterior including at least one projection fixed onto the door or the other fixed structure and extending into the axial clearance and towards one of the fixed structure or the door, while leaving an axial gap between a free end of said projection and one of the fixed structure or the door.