Vane Support Seal Structure for CMC Thermal Stress Compliance
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Solution Overview
Problem
Implementing ceramic matrix composite (CMC) materials in gas turbine engine airfoils poses unique challenges due to their high temperature resistance, including thermal expansion mismatches and potential for thermal stress, which can lead to structural integrity issues and reduced durability.
Innovation Solution
A gas turbine engine support system featuring a vane arc segment with a seal configuration that includes a first seal section with a floor wall and side walls forming disjointed corners, and a second seal section that nests with the first seal section to cover gaps, providing enhanced sealing and compliance to manage thermal stresses and prevent cooling air leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If CMC materials are used in airfoils for high temperature resistance, then temperature resistance is improved, but thermal stress and structural integrity deteriorate
Solution Approach 1:
The support system is divided into multiple arc segments that can independently expand and contract, allowing each segment to accommodate thermal stress without compromising the overall structural integrity of the CMC airfoil
Solution Approach 2:
The support system incorporates compliant features and disjointed corners that change geometric parameters under thermal load, enabling the structure to adapt to thermal expansion and contraction while maintaining strength
2Reliability
If a seal is used to prevent cooling air leakage, then sealing performance is improved, but thermal stress compliance deteriorates
Solution Approach 1:
The seal incorporates a flexible membrane that can deform under thermal stress while maintaining the sealing function, allowing the seal to comply with thermal expansion and contraction of the CMC airfoil
Solution Approach 2:
The second seal section nests within the first seal section, creating a hierarchical structure where the inner seal can move independently to accommodate thermal stress while the outer seal maintains the primary sealing function
3Strength
If a rigid seal structure is used to maintain structural integrity, then strength is improved, but sealing effectiveness deteriorates
Solution Approach 1:
The seal uses a flexible membrane structure that maintains overall structural integrity while allowing local deformation to ensure effective sealing against the rotating airfoil
Solution Approach 2:
The seal transitions from a static rigid structure to a dynamic flexible structure that can adapt its shape and position in response to rotating and thermal conditions, maintaining both strength and sealing effectiveness
Data Source
AI summary
A gas turbine engine support system includes a vane arc segment, a vane support arc segment piece configured to engage the vane arc segment, and a seal disposed radially between the vane arc segment and the vane support arc segment piece. The seal includes first and second seal sections. The first seal section has a floor wall and first and second side walls that project from the floor wall. The first and second side walls converge to define a disjointed corner. The second seal section nests with the first seal section and seals the disjointed corner.