Turbine Shroud Assembly CMC Segmentation Axial Pin Retention
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Solution Overview
Problem
Existing turbine ring assemblies in aeronautical gas turbine engines face challenges with cooling requirements, material limitations, and mass reduction, particularly due to the use of metal materials and the integration constraints of ceramic-matrix composite (CMC) materials.
Innovation Solution
The turbine ring assembly incorporates a plurality of ring sectors made of ceramic-matrix composite material, supported by a ring support structure with a shroud that includes upstream and downstream portions, allowing for reduced mass through material transfer and elimination of radial pins, and utilizing axial pins and compressive holding between radial clamps for secure attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal materials are used for the turbine ring, then structural strength and integration are ensured, but cooling requirements increase and mass increases
Solution Approach 1:
The turbine ring is constructed using ceramic-matrix composite (CMC) materials, specifically silicon carbide matrix composite (SiC/SiC), which provide high-temperature strength and structural integrity while being lighter than traditional metal materials. This composite material enables the ring to withstand thermal and mechanical loads without requiring extensive cooling, thereby reducing both mass and cooling requirements
2Weight of moving object
If CMC material is used for the turbine ring, then cooling requirements are reduced and mass is decreased, but integration complexity with metal components increases
Solution Approach 1:
The turbine ring is divided into multiple CMC sectors that are independently manufactured and then assembled together using metal connectors. This segmentation allows each sector to be optimized for CMC material properties while the metal connectors provide the necessary mechanical coupling and integration with the metal support structure, thereby managing integration complexity
Solution Approach 2:
Metal connectors and transition pieces serve as intermediaries between the CMC ring sectors and the metal support structure. These intermediary components facilitate the mechanical coupling of dissimilar materials, accommodating differences in thermal expansion, mechanical properties, and manufacturing processes while maintaining structural integrity
3Temperature
If cooling stream is increased for metal turbine ring, then thermal management is improved, but engine performance decreases due to reduced main stream flow
Solution Approach 1:
The use of CMC materials changes the thermal parameters of the turbine ring, allowing it to operate at higher temperatures without excessive cooling. The material's inherent thermal resistance and high-temperature strength enable the ring to withstand thermal loads with minimal cooling, thereby preserving main stream flow and engine performance
Data Source
AI summary
Turbine shroud assembly comprising sections (10) made from CMC and forming a shroud (1) and a support structure (3), each section having a base (12) with a radially internal face (12a) and a radially external face (12b), from which there extend in a projecting manner an upstream attachment lug (14) and a downstream attachment lug (16), the support structure comprising a collar (31), from which there radially extend in a projecting manner towards the shroud an upstream radial flange (32) and a downstream radial flange (36), by which the lugs of each section of the shroud are retained, the shroud (1) being retained by axial pins (119, 120) which cooperate, on the one hand, with the upstream radial flange, via first and second annular end plates (33, 34), and directly with the downstream radial flange and, on the other hand, with the upstream and downstream attachment lugs, respectively.