Turbine Ring Assembly with CMC Segments and Metallic Holding
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Solution Overview
Problem
Existing turbine ring assemblies using ceramic matrix composite (CMC) materials still require significant cooling flows and are subject to mechanical stresses due to hot expansion of metal attachment parts, which can lead to embrittlement of CMC ring sectors.
Innovation Solution
A turbine ring assembly design featuring CMC ring sectors with a metallic holding member that is protected from hot flows by the CMC material, providing thermal decoupling and using elastically deformable holding elements to compensate for thermal expansion, thereby reducing cooling gas requirements and mechanical stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal attachment parts are used to connect CMC ring sectors to the ring support structure, then the structural strength and connectivity are improved, but the metal parts are subjected to hot expansion and mechanical stressing which can lead to embrittlement of the CMC ring sectors
Solution Approach 1:
The holding member is extracted from the hot flow environment by placing it inside an internal housing of the CMC ring sector. The CMC material acts as a thermal barrier, protecting the metal holding member from direct exposure to hot gases, thereby preventing hot expansion and mechanical stressing that would lead to CMC embrittlement.
Solution Approach 2:
The CMC ring sector serves as an intermediary thermal barrier between the hot flow environment and the metal holding member. This intermediary structure protects the metal components from thermal exposure while maintaining structural connectivity, resolving the contradiction between strength and embrittlement resistance.
2Strength
If metal attachment parts are exposed to hot flow, then the structural connectivity is maintained, but significant cooling flows are required to cool the metal parts which reduces engine performance
Solution Approach 1:
The holding member is extracted from the hot flow zone and placed inside the internal housing of the CMC ring sector. This extraction eliminates the need for significant cooling flows to protect the metal holding member from thermal exposure, thereby reducing energy loss and improving engine performance while maintaining structural connectivity.
Solution Approach 2:
The CMC ring sector provides self-protection for the holding member by acting as an intrinsic thermal barrier. The structure serves itself by using its own material properties to protect the metal components, eliminating the need for external cooling systems and reducing energy consumption.
3Strength
If the holding member is made of metallic material, then the structural strength is improved, but the thermal expansion of the metal causes mechanical stress on the CMC ring sectors
Solution Approach 1:
The holding member is extracted from the hot flow environment by placing it inside the internal housing of the CMC ring sector. This extraction prevents thermal exposure and subsequent thermal expansion of the metal holding member, thereby eliminating the mechanical stress that would be transmitted to the CMC ring sectors while maintaining holding strength.
4Productivity
If CMC materials are used for the turbine ring, then the cooling flow requirement is reduced and performance is improved, but the existing assembly solutions still require metal attachment parts that need cooling and undergo hot expansion
Solution Approach 1:
The holding member is merged with the CMC ring sector structure by placing it inside the internal housing of the ring sector. This merging integrates the thermal protection function directly into the structural component, eliminating the need for separate cooling systems and reducing thermal management complexity while maintaining high engine performance.
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 design reduces the need for cooling gas, increases engine performance, and minimizes mechanical stress on CMC ring sectors by using the CMC material as a thermal barrier and allowing for differential expansion compensation.
Implementation Method 1
the CMC ring sector which has low thermal conductivity and thus constitutes a thermal barrier for the retaining member
Implementation Method 2
due to the thermal expansion of the metallic material of the holding member, the latter exerts pressure on the ring sector, thus making it possible to hold it in position during operation
Implementation Method 3
the holding elements can slide on the wall in the event of differential expansion and, consequently, to compensate for the differences in expansion between the retaining member and the ring sector
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The present invention relates to a turbine ring assembly comprising a plurality of ceramic matrix composite ring segments (1) and a ring support structure, each ring segment (1) having a part forming an annular base (2) with an internal face (3) defining the internal face of the turbine ring and an external face (3a) from which there extends a wall (5) delimiting an internal housing (6) in which a metallic material retaining member (10) is housed, the retaining member (10) being connected to the ring support structure and comprising a body (11) from which elastically deformable retaining elements (12) extend into the internal housing (6) on each side of the body (11), the retaining elements (12) bearing against the wall (5).