Variable Thickness Casting Core for Blade Outer Air Seal Adaptability

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Solution Overview

Problem

Traditional Blade Outer Air Seal (BOAS) casting cores require predetermined flow paths, making it difficult to accommodate changes in cooling requirements across the BOAS, especially due to varying pressure ratios between cooling air and working air at different edges, limiting adaptability during engine development cycles.

Innovation Solution

A casting core with refractory metal components of variable thickness, where the heat exchange cavity core sections are machined to reduce thickness and drilled to create flexible airflow paths, allowing for changes in inlet and exit configurations and flow directions, enabling more efficient cooling and adaptability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional refractory metal cores with constant thickness are used, then the structure is simple and manufacturing is straightforward, but the flow path cannot be changed without revising tooling

Engineering Contradiction:
Improveadaptability of flow pathVSAvoidcore structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The core structure implements variable thickness design where different sections have different thicknesses to optimize cooling performance. The core includes a first section with a first thickness and a second section with a second thickness different from the first, allowing localized optimization of heat exchange characteristics in different regions of the BOAS.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention introduces adjustable flow path configurations that can be modified without changing the core tooling. The core structure allows for different flow path arrangements (first flow path, second flow path, third flow path) to be implemented by adjusting the BOAS manufacturing parameters rather than redesigning the core itself, enabling dynamic adaptation to changing cooling requirements.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If predetermined flow paths are used in traditional cores, then manufacturing precision is maintained, but adaptability to changing cooling requirements is lost

Engineering Contradiction:
Improveadaptability to cooling requirementsVSAvoidflow path definition precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The core structure is pre-designed with variable thickness sections and multiple potential flow path configurations built into the tooling. This preliminary preparation allows different flow paths to be selected and implemented during manufacturing without requiring tooling revisions, maintaining precision while enabling adaptability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention enables parameter changes in flow path configuration by modifying manufacturing parameters rather than core geometry. The core structure supports different flow path arrangements (first, second, and third flow paths) achieved through parameter adjustments in the BOAS manufacturing process, allowing precise control adaptable to varying cooling needs.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If constant thickness cores are used, then ease of manufacture is improved, but cooling efficiency varies poorly across different BOAS sections

Engineering Contradiction:
Improvecore manufacturing easeVSAvoidcooling efficiency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The core implements variable thickness design with a first section having a first thickness and a second section having a second thickness, allowing each section to be optimized for its specific thermal requirements. This local quality differentiation improves cooling efficiency in high-temperature regions while maintaining manufacturability through systematic design.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the thickness parameter of the core structure from constant to variable, creating sections with different thicknesses to optimize heat exchange. This parameter variation is integrated into the manufacturing process through controlled deposition or machining operations, maintaining ease of manufacture while significantly improving cooling reliability.

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

This approach allows for more efficient cooling by tailoring airflow paths to specific areas of the BOAS, improving heat transfer and reducing pressure drop, while enabling modifications to match changing engine requirements without revising tooling, enhancing the adaptability and performance of BOAS.

Implementation Method 1

The BOAS segments may be cast via an investment casting process. In an exemplary casting process, a casting core is used to form the cooling array.

Methodology Applied
Scientific EffectInvestment casting:

Implementation Method 2

Cooling air may be fed into the array from the outboard side of the BOAS then may exit through outlet ports in the circumferential ends (matefaces) of the BOAS so as to be vented into the adjacent inter-segment region

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

The BOAS segments may be cast via an investment casting process... the core forms the cooling passageway array in the casting

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 4

exit out the gas path radial surface to create film cooling

Methodology Applied
Scientific EffectFilm cooling:

Data Source

PatentEP3034808B1Casting core for blade outer air seal, blade outer air seal and corresponding manufacturing method
Publication Date: 2021.12.01 RTX CORP
  • EP3034808B1 patent drawingFigure 1
  • EP3034808B1 patent drawingFigure 2
  • EP3034808B1 patent drawingFigure 3

AI summary

A casting core (200) for a Blade Outer Air Seal includes a heat exchange cavity core section (152) in communication with a first plenum section (150) and a second plenum section (154), the first plenum section (150) and the second plenum section (154) being of a thickness greater than the heat exchange cavity section (152).