Ceramic Matrix Composite Blade Tip Crown for Rub Damage Protection
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Solution Overview
Problem
Gas turbine engine blades degrade due to interaction with blade tracks or other structures, leading to performance loss and material damage, as existing designs expose ceramic matrix composite materials to the environment and rub-related damage.
Innovation Solution
A turbine blade design featuring a ceramic matrix composite airfoil with a protective crown made of ceramic materials mounted radially outward, protected by a crown retainer that blocks radial motion, preventing exposure to the environment and rub damage, and incorporating features like flanges and channels for secure attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the turbine blade uses ceramic matrix composite materials for the airfoil, then the blade can operate at higher temperatures and improve engine performance, but the blade becomes more susceptible to environmental degradation and rub damage from interaction with blade tracks
Solution Approach 1:
The blade is divided into distinct functional zones: the airfoil made of ceramic matrix composite materials for high-temperature operation, and a protective crown made of more rub-resistant materials mounted at the radially outer end portion. This segmentation allows each part to perform its optimal function while protecting the vulnerable CMC materials from environmental degradation and rub damage.
Solution Approach 2:
The blade employs a composite structure combining ceramic matrix composite materials in the airfoil with a protective crown made of different ceramic-containing materials. This composite approach leverages the high-temperature capabilities of CMC while adding a protective layer that resists environmental degradation and mechanical damage from blade track interaction.
2Reliability
If a protective crown is mounted to the radially outer end portion of the airfoil to protect against rub damage, then blade durability is improved, but the device complexity increases due to additional components and assembly requirements
Solution Approach 1:
The protective crown is integrated with the airfoil through a crown retainer system where the retainer is incorporated into either the airfoil or the protective crown itself. The flange-receiving channel design merges the retention function into the existing structural components, reducing the need for separate fastening elements and simplifying the overall assembly.
Solution Approach 2:
The crown retainer features a flange that is received within a flange-receiving channel formed in the other component, creating a nested arrangement. This nesting approach provides secure attachment while minimizing the number of discrete parts and simplifying the assembly process compared to traditional fastening methods.
3Object-affected harmful factors
If the protective crown is positioned to engage the blade track directly, then the ceramic matrix composite materials are protected from rub damage, but the manufacturing precision requirements increase to ensure proper positioning and alignment
Solution Approach 1:
The protective crown is specifically positioned at the radially outer end portion of the airfoil where it directly engages the blade track, providing localized protection exactly where rub damage occurs. The flange-receiving channel is formed at the precise location needed to ensure proper alignment, concentrating manufacturing precision requirements only at critical interfaces rather than throughout the entire blade.
Data Source
AI summary
Turbine blades for use in gas turbine engines are disclosed herein. Each blade includes an airfoil and a protective crown. The airfoil includes ceramic matrix composite materials. The protective crown includes ceramic-containing materials and is mounted to a radially-outer end portion of the airfoil.