BOAS Casting Core with Connector Branches for Cooling
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Solution Overview
Problem
The existing casting processes for blade outer air seal (BOAS) segments in gas turbine engines face challenges in maintaining structural integrity and efficient cooling distribution due to the lack of local connection of core leg free distal ends to adjacent core end portions, which can compromise structural integrity and lead to suboptimal cooling performance.
Innovation Solution
A refractory metal core with free distal portions projecting transverse to the main body and connector branches connecting adjacent legs, allowing for the elimination or reduction of plug welding and enabling finer passageway casting with improved cooling distribution through dual or paired outlets, which are strategically angled to resist gas ingestion and enhance cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional ceramic cores with disconnected leg distal ends are used, then manufacturing simplicity is maintained, but structural integrity of the casting is compromised
Solution Approach 1:
The patent merges the disconnected leg distal ends with the core body by providing a continuous refractory material structure. The leg distal ends are connected to the core body through material continuity, eliminating gaps and ensuring structural integrity throughout the core assembly during casting.
Solution Approach 2:
The core is segmented into distinct functional regions: the core body, the legs, and the connected leg distal ends. This segmentation allows each part to serve its specific function while maintaining overall structural coherence through the connection feature.
2Strength
If plug welding is used to close end openings, then manufacturing process is simplified, but structural integrity and cooling distribution efficiency are reduced
Solution Approach 1:
The core structure is designed in advance with leg distal ends that extend into the shell cavity, pre-positioning the cooling air distribution points before casting. This preliminary configuration eliminates the need for post-casting plug welding to close end openings, as the structure is inherently closed and optimized for cooling distribution.
Solution Approach 2:
The patent extracts and eliminates the plug welding step from the manufacturing process. By designing the core with continuous structural integrity and integrated leg distal ends, the need for separate plug welding operations to close end openings is removed, simplifying the overall manufacturing process.
3Stability of the object's composition
If core leg distal ends are connected to core body, then structural integrity is improved, but core manufacturing complexity increases
Solution Approach 1:
The patent changes the geometric parameters of the core structure by extending the leg distal ends to connect with the core body. This parameter modification creates a continuous structural form that improves stability while remaining manufacturable using standard refractory forming techniques.
4Manufacturing precision
If finer passageway casting is achieved, then cooling distribution efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by providing different structural characteristics in different regions of the core. The leg distal ends that extend into the shell cavity are designed with specific geometric features that optimize local cooling air distribution, enabling finer and more efficient passageway casting in critical areas without requiring uniform high precision throughout the entire core.
Data Source
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AI summary
A blade outer air seal (BOAS) casting core (200) has first and second end portions (202, 204) and a plurality of legs. Of these legs, first legs (210, 214, 218) each have: a proximal end joining the first end portion; a main body portion; and a free distal portion. Second legs (212, 216, 220) each have: a proximal end joining the second end portion; a main body portion; and a free distal portion. Diverging branches (242, 243) are provided for forming diverging outlet passages in a blade outer air seal segment cast from the core.