Elastically Deformable Flange for CMC Turbine Ring Sealing
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Solution Overview
Problem
The sealing between ceramic matrix composite (CMC) ring sectors and metal ring support structures in turbine engines is compromised by differential thermal expansion, leading to potential damage and increased cooling ventilation requirements, and existing mounting methods are complex and costly.
Innovation Solution
A turbine ring assembly with elastically deformable annular flanges and a retention band featuring teeth for jaw coupling, which maintains contact between CMC ring sectors and metal flanges, accommodating thermal expansion and preventing excessive stress, while allowing easy mounting and removal of ring sectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If CMC ring sectors are used to reduce cooling ventilation requirements, then temperature resistance and efficiency are improved, but sealing reliability deteriorates due to differential thermal expansion between CMC tabs and metal flanges
Solution Approach 1:
The patent changes the mechanical parameter of the flange by making it elastically deformable in the axial direction. This allows the flange to adapt its position and maintain contact with the CMC tabs despite thermal expansion differences, preserving sealing reliability while using CMC materials for high temperature resistance.
Solution Approach 2:
The flange transitions from a rigid structure to a dynamic, elastically deformable component. This enables the flange to automatically adjust its position in response to thermal expansion forces, maintaining continuous contact with the CMC tabs and ensuring reliable sealing across temperature variations.
2Reliability
If rigid flanges are used to maintain contact with CMC tabs, then sealing is improved, but excessive stress and potential damage to tabs occur due to differential thermal expansion
Solution Approach 1:
The flange's mechanical parameter is changed from rigid to elastically deformable. This allows the flange to maintain sealing contact while accommodating thermal expansion forces through elastic deformation, preventing excessive stress concentration on the CMC tabs and avoiding potential damage.
3Reliability
If U-section clamps are used to hold ring sectors, then retention is achieved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts and eliminates the U-section clamp component from the assembly. The retention function is integrated directly into the simplified flange structure, which holds the ring sectors through its elastic deformation and contact pressure, thereby reducing device complexity and manufacturing cost while maintaining reliable retention.
Solution Approach 2:
The retention function previously performed by separate U-section clamps is merged into the flange structure itself. The flange combines both the sealing and retention functions in a single integrated component, simplifying the overall assembly and reducing the number of parts required.
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
The solution ensures reliable sealing and reduced stress on CMC ring sectors across varying temperatures, simplifies the assembly process, and maintains performance without excessive cooling demands, thereby enhancing the efficiency and durability of turbine engines.
Implementation Method 1
at least one of the flanges of the ring support structure being elastically deformable in the axial direction of the turbine ring
Implementation Method 2
differential expansion between the metal of the ring support structure and the CMC of the ring sectors
Implementation Method 3
the band has a first series of teeth distributed circumferentially on said band and the turbine casing has a second series of teeth distributed circumferentially on said casing, the teeth of the first series of teeth and the teeth of the second series of teeth together providing circumferential law coupling
Data Source
AI summary
A turbine ring assembly includes a plurality of ring sectors of ceramic matrix composite material forming a turbine ring and a ring support structure secured to a turbine casing and having two annular flanges, each ring sector having two tabs held between the two annular flanges. The ring support structure includes an annular retention band mounted on the turbine casing, the annular retention band including an annular web forming one of the flanges. The two annular flanges exert stress on the tabs of the ring sectors. One of the flanges is elastically deformable in the axial direction of the turbine ring. The band has a first series of teeth distributed circumferentially on the band and the turbine casing has a second series of teeth distributed circumferentially on the casing, and the teeth of the first series and the teeth of the second series together provide circumferential jaw coupling.