Ceramic Core Backstop for Gas Turbine Cooling Channel Drilling

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Solution Overview

Problem

The existing methods for forming micro-channel cooling in gas turbine engines, such as abrasive liquid jet drilling, often result in damage to the interior surfaces when creating access holes for coolant supply due to back-strike during the drilling process.

Innovation Solution

The use of a ceramic core as a backstop material within the component's interior space during the formation of access holes and grooves for micro-channel cooling, which absorbs and disperses the energy of the abrasive liquid jet, preventing damage and facilitating easier core removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If abrasive liquid jet drilling is used to form access holes, then coolant supply capability is improved, but interior surface damage occurs due to back-strike

Engineering Contradiction:

Improvecoolant supply capabilityVSAvoidinterior surface damage

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

A sacrificial core material is placed in the interior space to act as an intermediary that absorbs the back-strike from the abrasive liquid jet. This core material is designed to be eroded preferentially, protecting the component's interior surface from damage while still allowing coolant flow paths to be formed.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful back-strike energy that would normally damage the interior surface is redirected onto a sacrificial core material. The core is intentionally designed to withstand and absorb this harmful energy, converting it into a useful function by protecting the actual component surface while facilitating access hole formation.

Inventive Principle:

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

2Object-affected harmful factors

If core material is used to protect interior surfaces, then surface damage is prevented, but core removal complexity increases

Engineering Contradiction:

Improvesurface damage preventionVSAvoidcore removal process

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The sacrificial core material is selected with specific physical and chemical properties that differ from the component material, particularly in terms of solubility or reactivity. This allows the core to be removed through chemical dissolution or erosion processes after it has served its protective function, simplifying the removal operation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The core material is designed as a temporary, disposable element that is discarded after serving its protective purpose. The removal process is simplified by designing the core to be easily dissolved, eroded, or fragmented, allowing it to be discarded without complex retrieval operations.

Inventive Principle:

Principle #34Discarding and recovering

3Weight of moving object

If thin walls of superalloy metals are used, then component weight is reduced, but cooling requirements increase

Engineering Contradiction:

Improvecomponent weightVSAvoidcooling requirements

Core Design Contradiction:

Weight of moving objectVSTemperature

Solution Approach 1:

The cooling system is segmented into multiple access holes and internal coolant channels distributed throughout the component. This segmentation allows efficient heat removal from thin-walled structures by providing multiple coolant flow paths, compensating for the reduced thermal mass of thin walls while maintaining low weight.

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

This approach effectively prevents back-strike damage and simplifies the core removal process, enhancing the efficiency and reliability of micro-channel cooling in gas turbine components.

Implementation Method 1

when abrasive liquid jet (ALJ) drilling is used to make access (coolant supply) holes

Methodology Applied

Scientific EffectAbrasion: Abrasion

Implementation Method 2

the ALJ can also strike the interior surface of the opposite wall, thereby damaging that surface... a ceramic core as a backstop material... absorbs and disperses the energy of the abrasive liquid jet

Methodology Applied

Scientific EffectEnergy absorption and dispersion: Absorption (physical)

Data Source

PatentUS9242294B2Methods of forming cooling channels using backstrike protection

Publication Date: 2016.01.26 GE INFRASTRUCTURE TECH LLC

AI summary

A method of forming cooling channels in a component is provided. The component has a substrate having outer and inner surfaces. The inner surface defines at least one interior space, and a core is disposed within each interior space. The method includes forming at least one access hole in the substrate, while the core is disposed within the respective interior space, removing the core from the respective interior space, and forming at least one groove in the outer substrate surface (before or after the core is removed). Each access hole connects the groove in fluid communication with the respective interior space. The method further includes disposing a coating over at least a portion of the outer substrate surface, where the coating includes at least a structural coating that extends over the groove(s), such that the groove(s) and the structural coating together define one or more channels configured to convey a coolant from the respective interior space(s) for cooling the component.