Elastically Deformable Flange for CMC Turbine Ring Assembly
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Solution Overview
Problem
Ceramic matrix composite (CMC) turbine ring sectors face challenges in maintaining position and controlling shape due to differential expansions between metal support structures and CMC materials, leading to potential damage and performance issues in gas turbine engines.
Innovation Solution
A turbine ring assembly design featuring CMC ring sectors with S-shaped tabs held by annular flanges, where tabs are secured by holder and clamping elements, ensuring balanced holding with minimal bearing area to reduce stress and weight, and incorporating an elastically deformable flange to manage thermal expansion differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If CMC ring sectors are assembled with metal support structure, then the turbine can operate at higher temperatures, but differential thermal expansion causes clearance issues and potential damage to CMC sectors
Solution Approach 1:
The flange is designed to be elastically deformable, allowing it to dynamically adjust and absorb differential thermal expansion between the metal support structure and CMC ring sectors. This dynamic flexibility prevents clearance issues and potential damage while maintaining reliable positioning at high temperatures.
Solution Approach 2:
The invention changes the mechanical parameter of the flange from rigid to elastically deformable, enabling it to accommodate thermal expansion differences through elastic deformation rather than maintaining fixed rigid connections, thus preventing CMC sector damage.
2Reliability
If clearance is provided between CMC ring sectors and metal support structure, then thermal expansion damage is reduced, but control over flow passage shape and vibration control deteriorate
Solution Approach 1:
The elastically deformable flange provides dynamic adjustment capability, allowing the system to maintain precise flow passage shape control through elastic deformation rather than requiring fixed clearances, thus eliminating vibration issues while protecting CMC sectors.
3Manufacturing precision
If CMC ring sectors are held firmly in position, then flow passage shape control is improved, but stress on CMC sectors during thermal expansion increases
Solution Approach 1:
Changing the flange from rigid to elastically deformable allows the system to maintain firm positioning for flow passage shape control while the elastic parameter absorbs thermal expansion stress, preventing excessive stress on CMC sectors.
4Device complexity
If traditional rigid holding structures are used, then structural simplicity is maintained, but weight and stress concentration increase
Solution Approach 1:
The flange is designed to be elastically deformable rather than rigid, which maintains structural simplicity while reducing weight through optimized material usage and eliminating stress concentration issues associated with rigid connections.
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 design effectively maintains CMC ring sectors in position without clearance, reducing stress and weight, while ensuring controlled sealing and performance stability across temperature variations.
Implementation Method 1
the face of the first tab of each ring sector that faces inwards in the radial direction of the turbine ring rests on first and second holder elements secured to the first annular flange, the face of said first tab of each ring sector that faces outwards in the radial direction of the turbine ring being in contact with first and second clamping elements secured to the ring support structure
Implementation Method 2
the ring support structure being made of a material having a coefficient of thermal expansion that is greater than the coefficient of thermal expansion of the ceramic matrix composite material of the ring sectors
Implementation Method 3
incorporating an elastically deformable flange to manage thermal expansion differences
Implementation Method 4
ensuring balanced holding with minimal bearing area to reduce stress and weight
Data Source
AI summary
A turbine ring assembly comprises a plurality of ring sectors made of ceramic matrix composite material forming a turbine ring and a ring support structure including first and second annular flanges. In section, each ring sector presents a K-shape having an annular base-forming portion with an inside face defining the inside face of the turbine ring and an outside face with first and second S-shaped tabs projecting therefrom. The inside faces of the first and second tabs of each ring sector rest on holder elements secured to the first and second annular flanges, while the outside faces of the first and second tabs are in contact with clamping elements secured to the ring support structure.