Turbine Shroud Insert Repair for Worn Vane Slots

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Solution Overview

Problem

The outlet guide vane shroud assembly in turbine engines often experiences worn vane location slots due to operational stresses, leading to oversized slots and a need for part replacement, resulting in high scrap rates and costly replacements.

Innovation Solution

A method involving the removal of aperture liners, machining of the shroud ring to repair defects, securing a replacement insert with adhesive, and curing under pressure to restore acceptable tolerances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the outlet guide vane shroud assembly is used during engine operation, then the vane location slots become worn and oversized, but replacing the entire assembly is expensive and results in high scrap rates

Engineering Contradiction:
Improveslot dimensional toleranceVSAvoidpart replacement cost
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The shroud assembly is segmented into the shroud body and replaceable insert components. The insert contains the vane location slots and can be independently replaced when worn, rather than replacing the entire shroud assembly. This segmentation allows selective replacement of only the worn insert portion, reducing material waste and cost.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The worn insert is removed and discarded, while the main shroud body is retained and reused. The insert can be manufactured anew or refurbished, allowing recovery of the expensive shroud structure while replacing only the worn consumable insert component.

Inventive Principle:
Principle #34Discarding and recovering

2Ease of manufacture

If the vane location slots are allowed to wear during operation, then the insert serves as a wear part, but the slots eventually become oversized and require total part replacement

Engineering Contradiction:
Improveinsert replaceabilityVSAvoidslot dimensional tolerance
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The shroud assembly is segmented into the shroud body and replaceable insert components. The insert contains the vane location slots and can be independently replaced when worn, rather than replacing the entire shroud assembly. This segmentation allows selective replacement of only the worn insert portion, reducing material waste and cost.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The insert is designed as a disposable wear part that is intentionally made sacrificial. It is replaced when worn out, while the expensive shroud body is retained. This approach treats the insert as a consumable component that protects the main structure from wear.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Strength

If adhesive is applied to secure the insert in the shroud ring, then a strong bond is achieved, but the adhesive requires curing time and pressure application

Engineering Contradiction:
Improveinsert-to-shroud bond strengthVSAvoidadhesive curing time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The shroud ring and insert are pre-machined with complementary surfaces that ensure proper alignment and fit before adhesive application. This preliminary precision work reduces the tolerance requirements during bonding, allowing for faster curing times and reducing the need for extended pressure application.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The adhesive bonding process utilizes controlled temperature and pressure parameters to accelerate curing. By applying heat and pressure during the bonding operation, the curing time is reduced while still achieving the required bond strength, thus resolving the contradiction between bond strength and curing time.

Inventive Principle:
Principle #35Parameter changes

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 method allows for the economical and efficient repair of worn slots, reducing the need for total part replacement and enabling multiple repairs without sacrificing performance.

Implementation Method 1

applying an adhesive to a joint between the shroud ring and the insert

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

applying pressure to the joint

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP2025865B1Fan outlet guide vane shroud insert repair
Publication Date: 2013.11.06 UNITED TECH CORP
  • EP2025865B1 patent drawingFigure 1
  • EP2025865B1 patent drawingFigure 2~3
  • EP2025865B1 patent drawingFigure 4~5

AI summary

A method of repairing a turbine engine component that contains a series of lined apertures (50). The component is removed from the engine (10), and then at least one of the aperture liners (38) is also removed. The area adjacent the aperture (50) is machined to remove a portion of the parent material of the component. An insert (72) which replaces the material removed by machining is secured adjacent the aperture (50). The liner (38,82) about the aperture (50) is then replaced.