Ceramic Blade Attachment in Gas Turbine Wheel Assembly
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Solution Overview
Problem
Supporting and retaining ceramic blades in gas turbine engines is challenging due to the high heat and stress from combustion products, requiring innovative attachment solutions that manage centrifugal loads and thermal expansion.
Innovation Solution
A wheel assembly design featuring a disk with dovetail-shaped slots and platforms with dovetail-shaped attachment features, including pins, to securely couple ceramic blades with the disk, distributing loads and reducing stress on the blades.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If ceramic blades are used to withstand high heat from combustion products, then temperature resistance is improved, but the difficulty of supporting and retaining the blades increases due to centrifugal loads and thermal expansion
Solution Approach 1:
The blade assembly is segmented into multiple components: the ceramic blade, the metallic platform, and the attachment features. The platform acts as an intermediary structure that separates the blade retention function from the heat resistance function, allowing each component to be optimized for its specific purpose
Solution Approach 2:
The metallic platform serves as an intermediary between the ceramic blade and the disk. It provides a robust attachment mechanism with dovetail-shaped features that handle centrifugal loads and thermal expansion, while the ceramic blade focuses on withstanding high temperatures
2Power
If multiple blades are added to increase energy extraction, then power output is improved, but the structural integrity and stress distribution become more challenging to maintain
Solution Approach 1:
By segmenting the blade support function into separate platforms and attachment features, each blade can be independently supported with optimized stress distribution. This modular approach allows multiple blades to be added without compromising the structural integrity of individual blade attachments
Solution Approach 2:
The attachment features are designed with local quality optimization - the dovetail-shaped geometry provides enhanced load distribution at critical stress points, while the metallic platform material provides localized strength where needed without adding overall weight
3Ease of manufacture
If traditional blade support methods are used, then manufacturing simplicity is maintained, but the ability to reduce weight and handle centrifugal loads is insufficient
Solution Approach 1:
The blade assembly uses composite construction with ceramic blades for heat resistance and metallic platforms for mechanical support. This composite approach reduces overall weight compared to traditional all-metallic designs while maintaining the necessary strength and heat resistance properties
Data Source
AI summary
A wheel assembly for a gas turbine engine includes a disk, a plurality of blades, and a plurality of platforms. The disk is configured to rotate about an axis during operation of the gas turbine engine. Each of the plurality of blades includes a root received in the disk and an airfoil that extends radially away from the root. The platforms are arranged around the blades to define a boundary of a flow path of the gas turbine engine.