Turbine Vane Sealing with Floating CMC Seal
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Solution Overview
Problem
Gas turbine engines face challenges in designing airfoil components that balance high-temperature resistance with structural strength, particularly due to the differing thermal expansion coefficients and strength capabilities of ceramic matrix composite and metallic materials, leading to issues with sealing and stress distribution.
Innovation Solution
The airfoil assembly incorporates a ceramic matrix composite vane, a metallic support strut, and an inner carrier with floating seals that block hot gases from flowing radially inward, reducing force loads on the vane and allowing for relative thermal growth, while maintaining sealing effectiveness across varying temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If ceramic matrix composite materials are used for high-temperature resistance, then temperature resistance is improved, but structural strength deteriorates
Solution Approach 1:
The patent uses ceramic matrix composite (CMC) materials that combine ceramic fibers embedded in a ceramic matrix, creating a material that maintains both high-temperature resistance and structural strength. The composite structure allows the material to withstand thermal environments while retaining mechanical integrity through the reinforcing fiber network.
2Temperature
If ceramic matrix composite vanes are used, then temperature resistance is improved, but sealing performance deteriorates due to differing thermal expansion coefficients
Solution Approach 1:
The patent introduces a floating seal as an intermediary component between the CMC vane and the metallic support strut. This floating seal accommodates the differential thermal expansion between the two materials, maintaining sealing effectiveness across varying temperatures without compromising the integrity of either component.
Solution Approach 2:
The patent designs the floating seal system to explicitly accommodate thermal expansion differences between ceramic matrix composite and metallic materials. The floating seal can move radially to maintain contact and sealing as components expand or contract at different rates during temperature cycles.
3Reliability
If traditional sealing solutions are used, then sealing is provided, but stress concentration occurs on ceramic matrix composite components
Solution Approach 1:
The patent employs a dynamic floating seal that can move radially rather than being fixed in position. This dynamic capability allows the seal to self-adjust and distribute contact forces, preventing stress concentration on the brittle CMC vane while maintaining sealing effectiveness under varying thermal and pressure conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances the durability and sealing performance of airfoil assemblies by minimizing stress on ceramic matrix composite components and maintaining effective sealing despite large thermal expansions, outperforming traditional sealing solutions in high-temperature environments.
Implementation Method 1
The first floating ceramic matrix composite seal may be located between the metallic base mount and the inner platform to block the hot gases from flowing between the metallic base mount and the inner platform
Implementation Method 2
The first radially extending flange may allow for relative thermal growth between the first floating ceramic matrix composite seal, the metallic base mount, and the inner platform
Data Source
AI summary
An airfoil assembly for a gas turbine engine includes a vane, a support strut, and an inner carrier. The vane is adapted to interact with hot gases flowing around the airfoil assembly during use of the airfoil assembly. The support strut is located in an interior cavity formed in the vane and configured to receive force loads applied to the ceramic matrix composite vane by the hot gases. The inner carrier is coupled with the support strut and adapted to block the hot gases from flowing radially inward toward an axis of the gas turbine engine.