Compressor Airfoil Blend Repair Using Engine History Assessment

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Solution Overview

Problem

Current methods for repairing damaged airfoils in gas turbine engines often require removal of the engine for excessive blend sizes, leading to significant downtime and cost, as existing repair guidelines are conservative and do not account for the engine's operational history or the condition of other components.

Innovation Solution

A method and system that utilize statistical surrogate models to assess and recommend blend geometries based on the airfoil's history, engine conditions, and other components' conditions, allowing for in-engine repairs and reducing unnecessary work by considering factors like pressure, temperature, and cycle history, and providing instructions for reduced stress or lower thrust operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conservative blend size limits from guide manuals are applied, then safety and structural integrity are ensured, but repair flexibility is reduced and unnecessary engine removals occur

Engineering Contradiction:
Improveairfoil structural integrityVSAvoidrepair flexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic repair guidelines that adapt blend size limits based on the engine's actual operational history, damage characteristics, and component condition. Instead of static conservative limits, the system calculates allowable blend sizes in real-time considering factors like cycle count, pressure-temperature exposure, and damage location, enabling flexible yet safe repairs

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the parameters used to determine blend limits from fixed manual values to dynamic values based on engine history data, damage geometry, and structural assessments. This allows the blend size limits to be optimized for each specific case rather than applying uniform conservative restrictions

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If engine removal is performed for excessive blend sizes, then complete repair capability is achieved, but maintenance downtime and cost increase significantly

Engineering Contradiction:
Improvecomplete repair capabilityVSAvoidmaintenance downtime
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The system performs preliminary assessments of engine history, damage characteristics, and structural integrity before determining repair requirements. By evaluating whether a blend can be safely performed in-engine based on pre-analysis of engine conditions and damage parameters, the system avoids unnecessary engine removals and reduces maintenance downtime

Inventive Principle:
Principle #10Preliminary action

3Productivity

If in-engine blending is performed, then maintenance downtime is reduced, but repair precision and safety margins may be compromised

Engineering Contradiction:
Improvemaintenance efficiencyVSAvoidblend repair precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The system incorporates feedback loops where blend recommendations are generated based on engine history and damage assessment, then actual blend results and post-repair inspections are fed back into the system. This continuous feedback enables refinement of blend precision while maintaining in-engine repair efficiency

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces traditional mechanical inspection and measurement methods with advanced non-destructive testing techniques and digital modeling. This substitution enables precise blend geometry control and safety verification while performing repairs in-engine, maintaining both productivity and precision

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP3260656B1Method and system for repairing an airfoil of a compressor blade of a gas turbine engine
Publication Date: 2023.01.04 RTX CORP
  • EP3260656B1 patent drawingFigure 1A
  • EP3260656B1 patent drawingFigure 1B~1C
  • EP3260656B1 patent drawingFigure 2

AI summary

A method of developing a suggested blend repair to an airfoil (84) includes the steps of: (a) storing history with regard to a particular airfoil (84) in a particular engine (20); (b) taking information with regard to new damage to the particular airfoil (84); (c) reaching an initial blend recommendation based upon step (b); (d) assessing whether the initial blend recommendation of step (c) would be appropriate to repair the new damage based upon a consideration of steps (a) - (c); and (e) reporting a final blend recommendation. A corresponding airfoil repair recommendation system is also provided.