Nesting CMC Seal Segments for Gas Turbine Hot Gas Leakage
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Solution Overview
Problem
Current gas turbine engine blade outer air seal designs face challenges in maintaining effective sealing and durability at high temperatures, particularly in preventing hot gas leakage and managing thermal stress, which can lead to damage from oxidation.
Innovation Solution
The design incorporates ceramic matrix composite (CMC) seal segments with a tapered structure and notches, allowing for a nesting arrangement that minimizes hot gas leakage and provides self-sealing capabilities, reducing the need for additional attachment structures and enhancing load sharing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional air seal designs are used in high temperature areas, then sealing function is provided, but durability deteriorates due to high temperature oxidization damage
Solution Approach 1:
The patent applies ceramic matrix composite (CMC) material for the air seal segments in high temperature areas. CMC provides both the necessary mechanical properties for sealing and resistance to high temperature oxidization, thereby improving reliability while protecting against thermal damage.
2Object-affected harmful factors
If blade outer air seals are made of ceramic matrix composite, then resistance to high temperature oxidization is improved, but manufacturing complexity increases
Solution Approach 1:
The air seal is divided into multiple arcuate seal segments that can be manufactured separately and then assembled. This segmentation allows for simpler manufacturing of individual CMC segments while achieving the complete sealing function when assembled together, reducing overall manufacturing complexity.
Solution Approach 2:
The patent employs a nesting arrangement where seal segments are positioned with tapered surfaces that interlock. The segments nest together to form a complete circular seal, allowing for easier assembly and manufacturing while maintaining the high temperature resistance properties of CMC material.
3Object-generated harmful factors
If seal segments are arranged in a nesting configuration, then hot gas leakage is reduced, but device complexity increases due to tapered surfaces and notches
Solution Approach 1:
The seal segments feature asymmetric tapered surfaces with different angles on adjacent segments. This asymmetric geometry creates an interference fit that prevents hot gas leakage while the modular segment design keeps the overall device complexity manageable through standardized component repetition.
Data Source
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AI summary
A component (105A, 105B) for a gas turbine engine (20) includes a body that has a first circumferential side (CI) and a second circumferential side (C2). A circumferentially extending passage (138) extends from the first circumferential side (CI) to the second circumferential side (C2). The first circumferential side (CI) has an outer height (H4) that is less than an inner height (H3) of the second circumferential side (C2).