CMC Turbine Nozzle Finger Interleaving for Joint Integrity
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Solution Overview
Problem
Conventional gas turbine nozzles face inefficiencies due to high cooling air requirements and stress issues at joints between airfoil bodies and platform walls, leading to potential cracking and reduced durability in ceramic matrix composite (CMC) components.
Innovation Solution
The use of ceramic matrix composite (CMC) turbine nozzles with a design featuring core plies, composite wrap plies with unidirectional fibers oriented in parallel and transverse directions, and edges cut into fingers to be interleaved between platform plies, enhancing the structural integrity and reducing stress at joints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If ceramic matrix composite (CMC) materials are used to withstand high temperature conditions, then cooling air requirements are reduced, but stress and cracking occur at joints between airfoil body and platform walls
Solution Approach 1:
The patent employs ceramic matrix composite materials with specific fiber orientations (0-degree and 90-degree plies) to create a composite structure that simultaneously achieves high temperature resistance and joint strength. The composite wrap plies are integrated between platform plies to reinforce joints while maintaining the thermal benefits of CMC materials.
Solution Approach 2:
The patent applies different fiber orientations at different locations within the nozzle structure. The composite wrap plies are specifically positioned at joint regions between the airfoil body and platform walls, providing localized reinforcement where stress concentration occurs, while other regions maintain optimized thermal properties.
2Ease of manufacture
If conventional assembly methods are used for CMC components, then manufacturing simplicity is maintained, but production time increases significantly
Solution Approach 1:
The patent merges multiple components (airfoil body, inner platform, outer platform) into a single integrated CMC structure manufactured as one piece. This eliminates the need for separate assembly operations while maintaining manufacturing simplicity, thereby significantly reducing production time without complicating the manufacturing process.
3Strength
If metal superalloy materials are used for turbine nozzles, then structural strength is achieved, but cooling air requirements increase and overall gas turbine efficiency decreases
Solution Approach 1:
The patent replaces conventional metal superalloys with ceramic matrix composite materials that possess superior high-temperature strength properties. The composite structure, with its fiber-reinforced architecture, provides adequate structural strength at operating temperatures without requiring extensive cooling air, thereby eliminating the trade-off between strength and cooling requirements that plagues metallic materials.
Data Source
AI summary
A ceramic matrix composite turbine nozzle includes a primary outer nozzle platform; a primary inner nozzle platform; and an airfoil-shaped body extending between the primary inner and primary outer nozzle platforms. The body includes core plies defining a cavity; composite wrap plies circumscribing the core plies and defining an airfoil shape; a secondary outer nozzle platform in contact with the primary outer nozzle platform; and a secondary inner nozzle platform in contact with the primary inner nozzle platform. Each composite wrap ply has two layers of unidirectional fibers oriented transverse to each other and has first and second longitudinal edges. The first and second longitudinal edges are cut into fingers, which are folded in a transverse direction away from a turbine nozzle longitudinal axis and are interleaved between platform plies to define the secondary inner nozzle platform and the secondary outer nozzle platform.