Variable Thickness Refractory Metal Core for Gas Turbine Cooling

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Solution Overview

Problem

The existing methods for forming cooling passages in gas turbine engine blade outer air seals using lost core molding are inefficient, requiring numerous combinations of augmentation features that are difficult to achieve and result in high tooling costs and long lead times.

Innovation Solution

The use of refractory metal cores with variable thickness to form cooling passages through processes like grinding, etching, EDM, and additive manufacturing, allowing for tailored cross-sectional areas and geometries to optimize cooling efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional lost core molding with augmentation features is used to form cooling passages, then cooling passages can be formed, but the process requires numerous combinations of augmentation features that are difficult to achieve and result in high tooling costs and long lead times

Engineering Contradiction:
Improvecooling passage configurationVSAvoidtooling complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by varying the thickness of the refractory metal core to control the cross-sectional area of cooling passages. Instead of using multiple augmentation features with different sizes and shapes, the core thickness is adjusted as a single parameter to achieve the desired cooling passage geometry. This simplifies the tooling design while maintaining manufacturing precision for the cooling passages.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If multiple combinations of augmentation features are used to achieve correct cooling value, then cooling efficiency can be optimized, but tooling costs and lead times increase

Engineering Contradiction:
Improvecooling efficiencyVSAvoidmanufacturing lead time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent uses parameter changes by modifying the core thickness to optimize cooling efficiency. This single parameter adjustment replaces the need for multiple augmentation feature combinations, thereby reducing the complexity of achieving the correct cooling value while shortening the manufacturing lead time.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The refractory metal core serves multiple functions: it forms the cooling passages, controls the cross-sectional area through thickness variation, and eliminates the need for separate augmentation features. This multi-functionality reduces the number of manufacturing steps and tooling requirements, thereby reducing lead time while maintaining cooling efficiency.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If multiple combinations of augmentation features are used to achieve correct cooling value, then cooling efficiency can be optimized, but tooling costs increase

Engineering Contradiction:
Improvecooling efficiencyVSAvoidtooling cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by using variable core thickness to control cooling passage cross-sectional area. This approach replaces the need for multiple types of augmentation features, thereby reducing tooling complexity and cost while maintaining the ability to optimize cooling efficiency through parameter adjustment.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The refractory metal core is designed to perform multiple functions including forming cooling passages and controlling their cross-sectional area through thickness variation. This universal approach eliminates the need for separate augmentation features and their associated tooling, thereby reducing manufacturing costs while maintaining cooling efficiency.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3196416B1Variable thickness core for manufacturing cooled gas turbine engine components
Publication Date: 2020.11.04 RTX CORP
  • EP3196416B1 patent drawingFigure 1
  • EP3196416B1 patent drawingFigure 2~4B
  • EP3196416B1 patent drawingFigure 5

AI summary

A gas turbine engine component has a body (82) extending between two circumferential sides (74,76), and between a leading edge (70;404) and a trailing edge (72). A refractory metal core (110;110A;110B;400) within the body (82) forms at least one cooling circuit (80) to utilize fluid to cool the body (82). When the refractory metal core (110;110A;110B;400) is removed from the body (82), the at least one cooling circuit (80) includes an inlet (86;420), an outlet (88), and a passage (84,84a;410) that varies in cross-sectional area (90,100) between the inlet (86;420) and outlet (88).