Abrasive Blade Tip Additive Prevents Clogging

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Solution Overview

Problem

Abrasive tips in turbomachines experience clogging due to the buildup of carbonized rub debris from abradable seals, which leads to frictional heating and potential thermal damage to the polyurethane erosion-resistant coating, contrary to the intended protection.

Innovation Solution

Applying an additive, such as metal stearate or palmitates, to the abrasive coated blade tip to prevent adhesion of organic components from the abradable seal, which is infiltrated into the porous structure of the tip to prevent clogging and frictional heating, and optionally heating the tip above the additive's melting point for better integration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If abrasive tips rub against abradable seals to remove portions of the seal, then clearance is maintained and blade protection is provided, but carbonized portions adhere to the abrasive tips causing clogging between grit particles

Engineering Contradiction:

Improveblade protectionVSAvoidclogging

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

A release agent comprising metal stearate particles is applied as an intermediary substance between the abrasive tip and abradable seal. The release agent prevents direct adhesion of carbonized seal material to the abrasive grit particles, allowing the abrasive action to continue without clogging. The metal stearate particles form a barrier layer that reduces sticking while maintaining the rubbing interface functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The surface chemistry of the abrasive tip is modified by applying the metal stearate release agent, changing the surface properties from adhesive to non-adhesive. This parameter change in surface energy and chemical composition prevents the carbonized portions from adhering to the grit particles, resolving the clogging issue while preserving the mechanical abrasion capability.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If clogging occurs between grit particles, then frictional heating increases during rub events, but this thermal effect damages the polyurethane erosion resistant coating on the blade

Engineering Contradiction:

Improvecoating protectionVSAvoidfrictional heating

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The metal stearate release agent serves as a thermal intermediary by preventing direct metal-to-metal and carbon-to-metal contact between the abrasive tip and seal. This reduction in direct frictional contact decreases heat generation at the interface, protecting the polyurethane coating from thermal damage while maintaining the necessary rubbing action for clearance control.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The rubbing interaction, which originally caused harmful heat generation and coating damage, is transformed into a beneficial process. By applying the release agent, the friction is controlled to generate minimal heat while maintaining the clearance-controlling function. The previously harmful frictional heating is converted into a controlled, beneficial rubbing action that protects the blade without damaging the coating.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If abrasive tips are designed to prevent thermal damage through abradable seals, then seal material should be removed cleanly, but carbonized portions build up and cause the very thermal damage intended to be prevented

Engineering Contradiction:

Improvethermal damage preventionVSAvoidabrasive tip cleanliness

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The metal stearate release agent is applied as a stable intermediary layer that prevents carbonized seal material from adhering to the abrasive tip surface. This intermediary layer maintains the compositional stability of the abrasive tip by preventing contamination and buildup, ensuring the tip remains clean and effective throughout operation without experiencing the thermal damage it was designed to prevent.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 additive effectively prevents clogging and frictional heating, maintaining the abrasive tip's cutting ability and extending the range of effective rub conditions while reducing thermal damage to the polyurethane coating.

Implementation Method 1

the additive is configured to prevent adhesion of an organic component of an abradable seal onto the abrasive coated blade tip

Methodology Applied

Scientific EffectLubrication: Lubrication

Implementation Method 2

wicking the additive into the abrasive coated blade tip

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 3

pressure infiltration with the additive into the pores

Methodology Applied

Scientific EffectPressure infiltration: Pressure Gradient

Implementation Method 4

heating the abrasive coated blade tip to a temperature above the melting point of the additive

Methodology Applied

Scientific EffectMelting: Melting

Data Source

PatentUS10422242B2Abrasive blade tips with additive resistant to clogging by organic matrix abradable

Publication Date: 2019.09.24 RTX CORP

AI summary

A method of applying an additive to an abrasive coated blade tip comprises applying the additive to the abrasive coated blade tip and wicking the additive into the abrasive coated blade tip, wherein the additive is configured to prevent adhesion of an organic component of an abradable seal onto the abrasive coated blade tip.