Abrasive Blade Tip Coating Thickness Control

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Solution Overview

Problem

Existing abradable coatings in turbomachines, such as gas turbine engines, face challenges in maintaining optimal clearance and efficiency due to issues like vibrational resonances and non-uniform rub responses, particularly at varying temperature zones within the engine.

Innovation Solution

A method for manufacturing a blade tip coating that includes a hardenable non-metallic matrix with abrasive particles and additional particulates, applied using a release member to achieve uniform thickness and improved wear resistance, allowing for precise control of abrasive content across different layers to optimize rub interaction and clearance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If glass micro-balloon filler is added to abradable coating, then effective modulus increases and deformation reduces, but vibrational resonances and non-uniform rub response occur

Engineering Contradiction:
Improveeffective modulusVSAvoidvibrational resonance uniformity
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the physical-chemical parameters of the coating by using a silicone resin matrix with specific Shore A hardness values (40-80) and controlling the filler content (0-60 weight percent). This parameter optimization allows the coating to achieve sufficient modulus while maintaining uniform rub response and reducing vibrational resonances through proper material selection and composition control.

Inventive Principle:
Principle #35Parameter changes

2Strength

If blade tip coating uses abrasive particles, then wear resistance improves, but manufacturing precision and uniform thickness control become difficult

Engineering Contradiction:
Improvewear resistanceVSAvoidcoating thickness uniformity
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent uses a silicone resin matrix as an intermediary binding medium that holds abrasive particles (such as alumina, silica, or diamond) in a controlled distribution. This matrix allows the abrasive particles to be uniformly distributed throughout the coating, achieving wear resistance while maintaining manufacturing precision and uniform thickness control through the resin's adhesive and cohesive properties.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If abradable coating is used to protect blade tips, then blade damage is limited, but clearance between blades and case increases

Engineering Contradiction:
Improveblade tip protectionVSAvoidclearance
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The patent optimizes the coating parameters including Shore A hardness (40-80), thickness (0.002-0.020 inches), and filler content to achieve the right balance between protection and clearance. By controlling these parameters, the coating provides adequate blade tip protection while maintaining smaller clearances through proper material selection and thickness control, preventing excessive wear and maintaining aerodynamic efficiency.

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

The solution effectively reduces blade tip damage, maintains low temperatures, and enhances efficiency by providing an engineered wear ratio, resulting in smaller clearance and improved aerodynamic performance.

Implementation Method 1

A release member bearing a release coating or agent is then compressed against the substrate

Methodology Applied
Scientific EffectRelease coating effect:

Implementation Method 2

The mixture is then compressed. Exemplary compression involves compressing against a release member

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 3

A method for manufacturing a blade tip coating that includes a hardenable non-metallic matrix with abrasive particles

Methodology Applied
Scientific EffectPhase change: Phase Change

Data Source

PatentEP2924242B1Abrasive tip blade manufacture methods
Publication Date: 2021.04.28 RTX CORP
  • EP2924242B1 patent drawingFigure 1
  • EP2924242B1 patent drawingFigure 2
  • EP2924242B1 patent drawingFigure 2A

AI summary

A method is disclosed for manufacturing a blade tip coating. The blade tip coating (152) comprising an abrasive (156) and a matrix (154). The method comprises forming a mixture comprising the abrasive (156), a precursor of the matrix (154), and an additional particulate (158). The mixture is pressed, the additional particulate (158) acting as a stop to limit thickness reduction of the mixture.