Wear Indicator for Gas Turbine Blade Tip Clearance

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Solution Overview

Problem

Accurate monitoring of blade tip clearance in gas turbine engines is challenging due to reduced clearance between blades and inner surfaces, which affects performance and requires precise measurement techniques.

Innovation Solution

A wear indicator with a conical frustum shape and inscribed measurement scale is attached to the inner surface of the gas turbine engine, featuring a constant inner diameter orifice and varying surface areas, allowing for material removal and photographic measurement capture to determine blade clearance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the clearance between blades and inner surfaces is reduced to improve performance, then engine performance is improved, but measurement precision deteriorates due to the reduced clearance making accurate monitoring more difficult

Engineering Contradiction:
Improveengine performanceVSAvoidblade clearance measurement
Core Design Contradiction:
PowerVSMeasurement precision

Solution Approach 1:

The wear indicator transitions the measurement from a direct linear clearance measurement to a radial dimension measurement. By attaching the indicator to the inner surface and measuring material removal radially outward, the system converts the difficult tangential clearance measurement into an easier radial measurement that can be captured photographically with higher precision.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The wear indicator acts as an intermediary between the blade tip and the measurement system. Instead of directly measuring the clearance between the blade and inner surface, the indicator material removal serves as a proxy measurement that can be captured indirectly through photographic imaging, resolving the measurement difficulty.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If traditional measurement methods are used for blade tip clearance, then device complexity is low, but measurement precision deteriorates due to inability to accurately monitor reduced clearance

Engineering Contradiction:
Improvemeasurement system complexityVSAvoidblade clearance measurement
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The system replaces complex mechanical measurement devices with a simpler photographic imaging system. Instead of using precision mechanical gauges or sensors to measure clearance, the wear indicator captures material removal data that can be measured through standard photographic imaging and image analysis, significantly reducing device complexity while improving measurement precision.

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

Solution Approach 2:

The wear indicator creates a physical copy or representation of the clearance condition through material removal patterns. The worn surface of the indicator replicates the clearance information in a form that can be captured by photography, allowing indirect measurement without complex direct measurement equipment.

Inventive Principle:
Principle #26Copying

3Measurement precision

If continuous monitoring of blade clearance is implemented, then measurement precision is improved, but loss of time increases due to required shutdowns for cooling and measurement capture

Engineering Contradiction:
Improveblade clearance measurementVSAvoidengine downtime for measurement
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The wear indicator is pre-installed on the inner surface before engine operation begins. This preliminary action allows the indicator to continuously record clearance information during engine operation without requiring real-time intervention. The measurement data accumulates during normal operation, and only periodic shutdowns are needed for data capture, minimizing time loss while maintaining measurement precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The wear indicator performs self-measurement by automatically recording material removal during engine operation. The indicator itself serves as both the measurement target and the measurement device, eliminating the need for external measurement equipment or complex monitoring systems that would require continuous operation and intervention.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3372794B1Wear indicator for gas turbine engine
Publication Date: 2021.06.09 RTX CORP
  • EP3372794B1 patent drawingFigure 1
  • EP3372794B1 patent drawingFigure 2
  • EP3372794B1 patent drawingFigure 3~4

AI summary

In combination a wear indicator (100) and a component of a gas turbine engine is provided. The wear indicator (100) is secured to a surface (72) of the component of the gas turbine engine. The wear indicator comprising: a first side (120) delaminates when impacted by a blade (55) of the gas turbine engine; a second side (130) parallel to the first side (120), the second side (130) being secured to a surface (72) of the component of the gas turbine engine; a mid-section (140) interposed between the first side (120) and the second side (130); and a reference dimension remains constant when the first side (120) delaminates.