Gas Turbine Cooling Hole Recoating Using Protective Gas Flow

Solution Overview

Problem

Existing coating repair methods for air-cooled gas turbine engine components, such as those with multiple cooling holes, are neither cost-effective nor operationally effective due to misalignment and duplication of cooling holes during recoating, as the original cooling hole locations are difficult to restore accurately.

Innovation Solution

A method involving the removal of prior coating layers, directing gas through cooling holes, and applying a new coat layer while maintaining gas flow through the holes to prevent recoat adhesion and ensure precise alignment, using techniques like plasma spray and gas pressure control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional coating repair methods are used to restore thermal barrier coatings on components with cooling holes, then the coating can be reapplied, but the cooling holes cannot be properly located due to recoat coverage, resulting in misaligned or duplicate cooling holes

Engineering Contradiction:

Improvecooling hole alignmentVSAvoidcoating repair process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by directing gas through the cooling holes before coating application. This pre-cooling step prevents the coating material from adhering to the cooling holes, ensuring they remain visible and accessible for proper location and alignment during the coating repair process, thereby avoiding misaligned or duplicate holes.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses gas (such as air or inert gas) as an intermediary substance. The gas is directed through the cooling holes during coating application to prevent coating material from blocking the holes. This intermediary gas layer allows the cooling holes to be maintained and properly located while still applying the thermal barrier coating over the component surface.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If cooling holes are re-drilled to restore alignment after coating repair, then cooling hole functionality can be restored, but the operation becomes costly and time-consuming

Engineering Contradiction:

Improvecooling hole functionalityVSAvoidrepair time and cost

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent applies preliminary action by directing gas through the cooling holes before coating application. This pre-cooling step prevents the coating material from adhering to the cooling holes, ensuring they remain visible and accessible for proper location and alignment during the coating repair process, thereby avoiding misaligned or duplicate holes.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses gas (such as air or inert gas) as an intermediary substance. The gas is directed through the cooling holes during coating application to prevent coating material from blocking the holes. This intermediary gas layer allows the cooling holes to be maintained and properly located while still applying the thermal barrier coating over the component surface.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If gas is directed through cooling holes during coating application, then cooling hole locations remain visible and aligned, but additional equipment and process complexity are required

Engineering Contradiction:

Improvecooling hole location accuracyVSAvoidcoating process equipment

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies pneumatic principles by using gas flow through the cooling holes to control coating material deposition. Gas sources such as compressed air lines or inert gas supplies are connected to the component, and the gas flow is directed through the cooling holes to prevent coating adhesion. This pneumatic approach provides precise control over cooling hole visibility and alignment during the coating process.

Inventive Principle:

Principle #29Pneumatics and hydraulics

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

This method effectively restores the component's thermal barrier while maintaining the integrity and alignment of cooling holes, reducing the need for costly re-drilling and misalignment issues, thereby enhancing operational efficiency and cost-effectiveness.

Implementation Method 1

directing a gas through at least one of the multiple of cooling holes, and applying a coat layer while directing the gas through at least one of the multiple of cooling holes

Methodology Applied

Scientific EffectGas flow protection:

Implementation Method 2

using techniques like plasma spray and gas pressure control

Methodology Applied

Scientific EffectPlasma spray: Plasma Spray

Data Source

PatentUS11143030B2Coating process for gas turbine engine component with cooling holes

Publication Date: 2021.10.12 RTX CORP

AI summary

A method of coating a component having a multiple of cooling holes includes removing at least a portion of a prior coating; directing a gas through at least one of the multiple of cooling holes; and applying a coat layer while directing the gas through at least one of the