PVB Core Inserts for Complex CMC Cooling Channels
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Solution Overview
Problem
Current methods for creating cooling structures in ceramic matrix composite (CMC) components are expensive, limited in flexibility, and unable to form complex or non-line of sight features, and do not allow for optimized fluid flow within cooling channels.
Innovation Solution
Incorporating polyvinyl butyral (PVB) core inserts with flow modification elements into CMC preforms, which are then removed through heat treatment to create internal cavities, allowing for complex cooling structures and optimized fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional drilling and machining methods are used to create cooling structures, then cooling channels can be formed, but the manufacturing cost increases and manufacturing flexibility is reduced
Solution Approach 1:
The patent applies preliminary action by embedding polymer core inserts with integrated flow modification elements into the CMC preform before densification. This allows the cooling channel geometry and flow control features to be pre-formed during the manufacturing process itself, rather than requiring subsequent drilling and machining operations. The core inserts are positioned in advance to define the exact cooling channel locations and configurations needed.
Solution Approach 2:
The patent uses polymer core inserts as intermediary objects that temporarily occupy the space where cooling channels will eventually form. These inserts serve as placeholders and form-defining tools during manufacturing, which are later removed to reveal the cooling channels. This intermediary approach enables complex geometries to be formed without requiring complex machining operations.
2Manufacturing precision
If mandrels are used during layup to create hollow cavities, then internal structures can be formed, but the method is expensive and limited to line of sight manufacturing
Solution Approach 1:
The patent applies the nested doll principle by integrating flow modification elements directly within the polymer core inserts. The flow modification elements are nested inside the core insert structure, allowing multiple functional features to be combined in a single component. This eliminates the need for separate mandrels and additional manufacturing steps, reducing cost while maintaining manufacturing precision.
Solution Approach 2:
The polymer core inserts serve multiple functions simultaneously: they define cooling channel geometry, provide structural support during densification, and integrate flow modification elements for fluid direction. This multi-functionality replaces the need for separate mandrels and flow control components, reducing manufacturing complexity and cost while achieving the desired internal structures.
3Productivity
If simple cooling channels are used, then manufacturing is easier, but cooling efficiency is reduced due to inability to optimize fluid flow
Solution Approach 1:
The patent applies local quality by incorporating flow modification elements at specific locations within the cooling channels where fluid flow optimization is needed. These elements are strategically positioned to create turbulence, direct flow patterns, or restrict flow at particular points, rather than requiring complex structures throughout the entire cooling channel system. This localized approach enhances cooling efficiency while maintaining overall manufacturing simplicity.
Solution Approach 2:
The flow modification elements act as intermediary structures within the cooling channels that mediate fluid flow characteristics. These elements are embedded in the cooling channel walls and serve to optimize coolant flow patterns, create turbulence for enhanced heat transfer, or direct flow to critical areas. They add functional complexity to simple cooling channel geometries, improving cooling efficiency without requiring complex channel configurations.
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 cost-effective, complex cooling channels with improved heat distribution and reduced thermal stress in CMC components by using PVB core inserts that are compatible with CMC materials and facilitate turbulence and direction of fluid flow.
Implementation Method 1
subjecting the preform with the one or more integrated polymer core inserts to a heat treatment to remove the base structures of the one or more polymer core inserts
Implementation Method 2
a binder that poses minimal or no chemical interaction with a CVI process
Data Source
Figure 1
Figure 2A~2E
Figure 3
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 (100a, 100b) having a base structure made of a fugitive material comprising polyvinyl butyral (PVB), and one or more flow modification elements (110a; 100b; 120a; 120b; 120c; 120d) made of a non-fugitive material. The preform with integrated polymer core inserts (100a, 100b) is subjected to a heat treatment to remove the PVB base structure made of the one or more polymer core inserts (100a, 100b) (e.g., by melting or burning) while retaining the one or more flow modification elements (110a... 120d). Removal of the PVB base structure forms one or more internal cavities within the composite with the one or more flow modification elements (110a... 120d) positioned therein. The preform can then be subjected to densification to form the CMC.