Blade Outer Air Seal Carrier with Radial Hooks
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Solution Overview
Problem
Existing blade outer air seal assemblies in gas turbine engines face challenges in maintaining effective sealing and stability, particularly with ceramic matrix composite materials which are hard and brittle, leading to wear and stress issues.
Innovation Solution
A blade outer air seal assembly design featuring a carrier with radially extending hooks and posts that engage with a support structure, incorporating a wear liner and feather seal to distribute loads and prevent rotation, while using ceramic matrix composite materials for the seal segments and metallic materials for the carrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ceramic matrix composite materials are used for blade outer air seal assemblies, then sealing effectiveness is improved, but wear and stress resistance deteriorate due to the hard and brittle nature of the material
Solution Approach 1:
The patent employs a composite structure combining ceramic matrix composite seal segments with a metallic carrier. The ceramic segments provide sealing effectiveness while the metallic carrier provides wear and stress resistance, creating a composite system that leverages the advantageous properties of both materials to resolve the contradiction between sealing performance and mechanical durability.
Solution Approach 2:
The metallic carrier acts as an intermediary structure that supports the ceramic seal segments. This intermediary component transfers and distributes mechanical stresses away from the brittle ceramic material, preventing stress concentration that would lead to cracking and failure, while allowing the ceramic segments to maintain their sealing function.
2Reliability
If ceramic matrix composite seal segments are used, then sealing performance is enhanced, but structural stability deteriorates due to the brittle nature of the material
Solution Approach 1:
The patent creates a composite assembly where rigid ceramic seal segments are mounted on a flexible metallic carrier. This composite structure provides structural stability through the metallic carrier while maintaining the sealing performance of the ceramic segments, resolving the contradiction between sealing effectiveness and structural stability.
Solution Approach 2:
The metallic carrier serves as a stabilizing intermediary that provides mechanical support and structural integrity to the brittle ceramic seal segments. This intermediary structure prevents deformation and maintains the positional stability of the seal segments during operation, while the ceramic material continues to provide effective sealing.
3Stability of the object's composition
If a carrier structure is added to support seal segments, then structural stability is improved, but device complexity increases
Solution Approach 1:
The patent merges the carrier structure with the seal segment mounting function into an integrated assembly. The carrier is designed with built-in features such as retaining rings and attachment mechanisms that simultaneously provide structural support and secure the seal segments, reducing the need for separate components and simplifying the overall assembly.
Solution Approach 2:
The metallic carrier performs multiple functions: it provides structural stability, supports the seal segments, distributes stresses, and facilitates assembly through integrated retaining features. This multi-functional design reduces the number of separate components needed, thereby reducing assembly complexity while maintaining structural stability.
Data Source
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AI summary
A blade outer air seal assembly (104) includes a seal segment (105) that has a base portion (124) that extends between a first circumferential side (C1) and a second circumferential side (C2) and from a first axial side (A1) to a second axial side (A2). A first wall (120) is axially spaced from a second wall (122). The first (120) and second walls (122) extend from the base portion (124) to an outer wall (126) to define a circumferentially extending seal passage (138). A carrier (112) has a platform (118). A portion of the platform (118) is within the seal passage (138). A radially extending first hook (114) protrudes from the platform (118) and is configured to engage with a support structure (110).