PVB Fugitive Cores for Ceramic Matrix Composite Cooling Channels

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Solution Overview

Problem

Current methods for creating cooling structures in ceramic matrix composite (CMC) components are expensive and limited in flexibility, unable to form ideal shapes and cooling features due to their unique manufacturing methods and material properties, and lack cost-effective means to create complex internal structures.

Innovation Solution

Incorporating polyvinyl butyral (PVB) core inserts into CMC preforms, which are then removed through heat treatment to form internal cavities, followed by densification to create ceramic matrix composite components with integrated cooling channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If drilling and machining holes, pockets or channels into CMC surfaces is used to create cooling structures, then cooling channels can be formed, but the manufacturing cost increases and manufacturing complexity increases

Engineering Contradiction:
Improvemanufacturing costVSAvoidcooling structure formation
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by embedding removable mandrels or cores into the CMC preform during the manufacturing process itself, rather than creating cooling channels after the component is made. This allows channels to be formed as integral features of the manufacturing process, eliminating expensive post-processing machining operations while maintaining precise channel geometry through the preform structure.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses the extraction principle by incorporating removable mandrels or core materials into the preform that are subsequently removed after densification. This extraction creates the cooling channels directly within the densified CMC structure, avoiding the need for costly drilling and machining operations while achieving the desired channel geometry.

Inventive Principle:
Principle #2Taking out (Extraction)

2Adaptability or versatility

If traditional machining techniques are used to create cooling structures, then cooling channels can be formed, but the flexibility and design freedom are limited

Engineering Contradiction:
Improvedesign flexibilityVSAvoidmanufacturing complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

By establishing the cooling channel geometry through mandrels or cores embedded in the preform before densification, the design flexibility is significantly enhanced. Complex three-dimensional channel shapes, varying cross-sections, and non-linear paths can be easily accommodated by simply changing the mandrel geometry, without requiring complex machining operations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent enables design flexibility through parameter changes by allowing easy modification of cooling channel geometry through different mandrel shapes, sizes, and configurations. This approach permits optimization of heat transfer characteristics by varying channel dimensions and patterns without increasing manufacturing complexity.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If cooling structures are added to CMC components to improve heat distribution, then thermal stress is reduced, but manufacturing cost and process complexity increase

Engineering Contradiction:
Improvethermal stress resistanceVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the cooling structure creation with the CMC manufacturing process itself by embedding mandrels or cores during preform assembly. This integration allows cooling channels to be formed as integral features without requiring separate manufacturing steps, thereby improving thermal stress resistance while avoiding additional process complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

By removing the mandrels or cores after densification, the patent creates cooling channels that improve thermal stress resistance. This extraction approach forms the cooling structures as integral parts of the component during manufacturing, rather than adding complex post-processing steps.

Inventive Principle:
Principle #2Taking out (Extraction)

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

Enables the formation of complex cooling circuits with improved heat distribution and reduced stress from thermal gradients, while being cost-effective and flexible in design, eliminating the need for expensive machining techniques.

Implementation Method 1

subjecting the preform with the one or more integrated polymer core inserts to a heat treatment to remove the one or more polymer core inserts

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Implementation Method 2

densifying the preform to form a ceramic matrix composite component with the one or more internal cavities

Methodology Applied
Scientific EffectDensification: Sintering

Data Source

PatentEP4628472A1Cores for ceramic matrix composite components
Publication Date: 2025.10.08 RTX CORP
  • EP4628472A1 patent drawingFigure 1~2
  • EP4628472A1 patent drawingFigure 3~4
  • EP4628472A1 patent drawing

AI summary

The preparation of ceramic matrix composite (CMCs) is disclosed in which a ceramic matrix composite (CMC) preform is made with one or more integrated polymer core inserts (30) made of a fugitive material containing polyvinyl butyral. The preform with integrated polymer core inserts (30) to a heat treatment to remove the one or more polymer core inserts (30) (e.g., by melting or burning). Removal of the polymer core inserts forms one or more internal cavities within the composite, which can then be subjected to densification.