Retractable Exhaust Liner Segment for Gas Turbine Maintenance

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Solution Overview

Problem

Existing gas turbine engine maintenance processes are inefficient, requiring significant time and labor to install or remove engines or power units, especially when maintenance within the airframe shadow is necessary, and existing solutions do not adequately address the need for quick and damage-free vertical removal and replacement.

Innovation Solution

A retractable exhaust liner segment with a split ring design and fastener assembly that allows axial installation and removal, providing clearance for the tail cone and ensuring a backpressure seal, manufactured from nickel alloy with high-temperature ceramic coating, and featuring a lap joint for insulation and captured fastener assemblies to prevent Foreign Object Damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If traditional engine installation and removal methods are used, then structural integrity is maintained, but maintenance time and labor requirements increase significantly

Engineering Contradiction:
Improvemaintenance timeVSAvoidexhaust liner structure
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The exhaust liner is divided into multiple segments that can be independently separated. The split ring design allows the exhaust liner to be divided into at least two segments, enabling vertical separation without requiring complete disassembly of the engine assembly, thus reducing maintenance time while managing structural complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The exhaust liner transitions from a fixed structure to a movable one. The retractable segments can move vertically along the engine axis, allowing dynamic adjustment during maintenance operations. This enables quick insertion and removal of engine components without permanent structural changes

Inventive Principle:
Principle #15Dynamics

2Productivity

If vertical removal and replacement of engines is implemented, then maintenance efficiency improves, but risk of damage to engine flanges increases

Engineering Contradiction:
Improvemaintenance efficiencyVSAvoidengine flange integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

Protective features are built into the exhaust liner segments before maintenance operations begin. The design includes protective edges and controlled separation mechanisms that prevent direct contact and potential damage between engine flanges and the exhaust liner during vertical removal, cushioning against harmful effects before they occur

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The exhaust liner segments act as intermediary components between the engine and the airframe structure. During vertical removal, these segments provide a buffer interface that protects the engine flanges from direct contact with potentially damaging structures, mediating the interaction to prevent damage

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If separable coupling with end flanges is used, then ease of assembly is improved, but sealing effectiveness and backpressure control deteriorate

Engineering Contradiction:
Improveassembly easeVSAvoidbackpressure seal
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The exhaust liner segments incorporate flexible sealing elements that can deform to maintain tight seals. The segmented design allows for flexible sealing interfaces that adapt to slight misalignments while maintaining effective sealing, preventing backpressure loss without requiring rigid precision coupling

Inventive Principle:
Principle #30Flexible shells and thin films

Data Source

PatentEP2594752B1Retractable exhaust liner segment for gas turbine engines
Publication Date: 2022.02.16 RTX CORP
  • EP2594752B1 patent drawingFigure 1
  • EP2594752B1 patent drawingFigure 2
  • EP2594752B1 patent drawingFigure 3

AI summary

A retractable exhaust liner segment (18) between a gas turbine engine (20) and an exhaust liner (16).