Air Seal Abrasive Coating Thickness Monitoring

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Solution Overview

Problem

Conventional abrasive coatings in turbine engine seals are difficult to non-destructively inspect for remaining thickness, leading to unnecessary refurbishment and maintenance, as the coatings wear down over time, making it challenging to determine if they have sufficient thickness for further use.

Innovation Solution

The introduction of an abrasive coating with an inner and outer matrix, each containing abrasive particles, where one of the matrices is modified with a first indicator material that can be detected to indicate the coating's thickness range, allowing for non-destructive inspection of the remaining coating thickness using energy outside the visible spectrum.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional abrasive coatings are used in turbine engine seals, then the coating provides protective abrasion resistance, but it becomes difficult to non-destructively inspect the remaining thickness

Engineering Contradiction:
Improveprotective abrasion resistanceVSAvoidremaining coating thickness
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies indicator materials with different colors or optical properties at different depths within the abrasive coating matrix. As the coating wears down, different colored regions become visible, providing visual indication of remaining thickness without requiring destructive inspection. This resolves the contradiction by enabling non-destructive thickness measurement while maintaining the coating's protective function.

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The patent introduces indicator materials as intermediary elements embedded within the abrasive coating matrix. These indicators serve as mediators between the coating structure and inspection methods, allowing thickness assessment through optical detection. The indicators do not interfere with the coating's abrasion resistance while enabling non-destructive evaluation of remaining thickness.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If all blades are sent for refurbishment at predetermined intervals, then maintenance is ensured, but unnecessary refurbishment occurs when coating thickness is still sufficient

Engineering Contradiction:
Improvemaintenance assuranceVSAvoidabrasive coating material
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent implements a feedback mechanism where the visual indicators in the coating provide real-time information about remaining thickness. This feedback allows maintenance personnel to make informed decisions about when refurbishment is actually needed, rather than following fixed schedules. The feedback loop prevents unnecessary refurbishment by showing when sufficient coating thickness remains.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the parameter of coating inspection from periodic scheduled checks to continuous visual monitoring through embedded indicators. This parameter change allows dynamic assessment of coating condition, enabling maintenance decisions based on actual wear state rather than predetermined time intervals, thereby reducing unnecessary refurbishment.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the abrasive coating is made thicker to ensure sufficient sealing, then sealing performance is improved, but the coating wears away faster and requires more frequent maintenance

Engineering Contradiction:
Improvesealing performanceVSAvoidcoating service life
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent segments the abrasive coating into multiple layers with different functions: outer abrasive layers for protection and cutting, and inner indicator layers for thickness monitoring. This segmentation allows optimization of each layer's thickness and composition, ensuring sufficient sealing performance while enabling precise tracking of wear to maximize service life without excessive material consumption.

Inventive Principle:
Principle #1Segmentation

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

Enables the estimation of the remaining abrasive coating thickness without damaging the component, allowing for more informed maintenance decisions and potentially extending the lifespan of the coatings by determining if they can last through another maintenance interval.

Implementation Method 1

energy outside the visible spectrum

Methodology Applied
Scientific EffectEnergy absorption outside visible spectrum: Absorption (EM radiation)

Data Source

PatentEP3263844B1Air seal abrasive coating and method
Publication Date: 2021.03.24 RTX CORP
  • EP3263844B1 patent drawingFigure 1
  • EP3263844B1 patent drawingFigure 2
  • EP3263844B1 patent drawingFigure 3

AI summary

An embodiment of a gas turbine engine component includes an abrasive coating disposed on at least a portion of a sealing region. The abrasive coating includes an inner abrasive region disposed outward of the sealing region in a coating thickness direction, and an outer abrasive region disposed outward of the inner abrasive region in the coating thickness direction. The inner abrasive region includes abrasive particles retained in an inner matrix, and the outer abrasive region includes abrasive particles retained in an outer matrix. At least one of the inner matrix and the outer matrix is modified with a first indicator material. At least one aspect of the first indicator material corresponds to a thickness range of the abrasive coating being within the inner thickness region or the outer thickness region.