Airfoil Cluster Repair Using Register Blocks

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Solution Overview

Problem

Current repair methods for airfoil clusters in gas turbine engines do not account for features like endwall contouring and serpentine passages, leading to challenges in precise alignment and effective repair.

Innovation Solution

The method involves attaching register blocks to the airfoil clusters, machining a datum system on these blocks for precise alignment, removing damaged portions using wire EDM, and joining salvaged parts through diffusion brazing to form a new, functional airfoil cluster while preserving the integrity of the serpentine passages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If current repair methods are used to cut and join airfoil clusters, then damaged parts can be replaced, but precise alignment of features like endwall contouring and serpentine passages cannot be achieved

Engineering Contradiction:
Improveairfoil cluster repairVSAvoidalignment of serpentine passages and endwall contouring
Core Design Contradiction:
Ease of repairVSManufacturing precision

Solution Approach 1:

Register blocks are attached to the airfoil clusters before the repair process begins. These blocks contain pre-machined datum surfaces that establish precise reference planes for alignment. By preparing these alignment features in advance, the patent enables accurate repositioning of salvaged airfoil clusters to match the original geometry of serpentine passages and endwall contouring.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The register blocks serve as intermediary elements between the salvaged airfoil clusters and the engine structure. These blocks provide standardized attachment and alignment interfaces that mediate the joining process, ensuring that complex features like serpentine passages and endwall contouring align precisely without requiring direct measurement and matching of the airfoil clusters themselves.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of substance

If salvaged parts are used for repair, then cost savings are achieved, but ensuring precise alignment and structural integrity becomes more difficult

Engineering Contradiction:
Improvematerial utilization efficiencyVSAvoidalignment and structural integrity
Core Design Contradiction:
Loss of substanceVSManufacturing precision

Solution Approach 1:

The airfoil cluster assembly is segmented into removable portions, with register blocks attached to facilitate independent handling and repositioning of salvaged segments. This segmentation allows damaged portions to be replaced while preserving intact sections, maximizing material utilization while maintaining precise alignment through the register block interface.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent enables recovery and reuse of salvaged airfoil clusters by providing a systematic method for their reattachment. Rather than discarding damaged clusters entirely, the register block system allows selective replacement of only the damaged portions while recovering and reusing intact salvaged sections, reducing material loss while ensuring proper alignment through standardized datum surfaces.

Inventive Principle:
Principle #34Discarding and recovering

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 approach ensures precise alignment and attachment of airfoil clusters, maintaining unimpeded airflow and supporting engine performance, while offering cost-saving benefits by utilizing salvaged parts.

Implementation Method 1

removing damaged portions with respect to the location of the serpentine passages using a wire electrical discharge machining process

Methodology Applied
Scientific EffectElectrical Discharge Machining: Electrical Discharge Machining

Implementation Method 2

joining the first and second airfoil clusters using a diffusion brazing process

Methodology Applied
Scientific EffectDiffusion Brazing: Diffusion Welding

Data Source

PatentEP2971519B1Method for working airfoil clusters of a gas turbine engine
Publication Date: 2020.10.28 RTX CORP
  • EP2971519B1 patent drawingFigure 1
  • EP2971519B1 patent drawingFigure 2
  • EP2971519B1 patent drawingFigure 3

AI summary

A method for working an airfoil cluster is disclosed. The method may include attaching a first datum to a first portion of the airfoil cluster, and joining a second portion of the airfoil cluster to the first portion, the second portion having a second datum substantially aligned with the first datum in a common plane spaced away from the first and second portions.