Elastically Deformable Flange for CMC Turbine Ring Retention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing turbine ring assemblies face challenges with sealing and assembly due to differential expansions between ceramic matrix composite (CMC) ring sectors and metal ring support structures, leading to potential damage and increased costs, as well as issues with maintaining the ring sectors in radial and circumferential positions.
Innovation Solution
A turbine ring assembly with annular flanges, where one flange is elastically deformable and includes pins and hooks for secure engagement of the CMC ring sectors, allowing for radial and circumferential positioning and accommodating thermal expansions, thereby ensuring consistent contact and reducing stress on the sectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If CMC ring sectors are used to reduce cooling requirements, then thermal efficiency is improved, but sealing reliability deteriorates due to differential expansion between CMC and metal components
Solution Approach 1:
The flange thickness is changed as a parameter to create elastic deformability. The first flange has a reduced thickness compared to the second flange, allowing it to deform elastically under thermal expansion/contraction cycles while maintaining continuous contact with the CMC ring sector tabs, thus preserving sealing reliability despite differential expansion.
Solution Approach 2:
The first flange is designed to be elastically deformable rather than rigid, allowing it to dynamically adapt its shape during thermal cycles. This dynamic capability enables the flange to maintain contact with the tabs throughout temperature variations, preventing seal loss while accommodating the different thermal expansion characteristics of CMC and metal materials.
2Strength
If rigid flanges are used to secure ring sectors, then structural strength is improved, but stress on CMC tabs increases during thermal expansion, potentially causing damage
Solution Approach 1:
The thickness parameter of the first flange is specifically reduced to create elastic deformability. This allows the flange to yield slightly during thermal expansion, reducing the peak stress transmitted to the CMC tabs while maintaining sufficient structural strength for normal operation through the second, thicker flange.
Solution Approach 2:
The elastically deformable first flange acts as a cushioning element that anticipates and absorbs thermal expansion stresses before they can damage the CMC tabs. The elastic deformation capacity is designed to accommodate expected thermal cycles, protecting the brittle CMC material from excessive stress.
3Reliability
If U-shaped clamps are used to secure ring sectors, then retention is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The retention function previously requiring separate U-shaped clamps is merged into the flange structure itself. The tabs extend between the two flanges, and the first elastically deformable flange provides both retention and stress accommodation functions that were previously distributed across multiple separate components, thereby reducing overall device complexity.
4Reliability
If pins are added to prevent radial and circumferential displacement, then positioning reliability is improved, but device complexity increases
Solution Approach 1:
The pins serve multiple functions simultaneously: they prevent radial displacement, prevent circumferential displacement, and provide alignment during assembly. By consolidating these multiple positioning functions into a single simple component, the overall complexity increase is minimized while achieving comprehensive positioning reliability.
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 effectively maintains the seal and positioning of the ring sectors across varying temperatures, preventing sliding or displacement, and simplifies the assembly process by using elastically deformable flanges and locking pins, ensuring reliable operation and reduced stress on the components.
Implementation Method 1
one of the flanges of the ring support structure being elastically deformable in the axial direction of the ring
Implementation Method 2
Differential expansion between the metal of the ring support structure and the CMC of the ring sectors complicates maintaining a seal between these components
Implementation Method 3
a plurality of pins engaged both in at least one of the annular flanges of the ring support structure and the lugs of the ring sectors opposite said at least one annular flange
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A turbine ring assembly comprises a plurality of ring sectors (10) made from a ceramic matrix composite material forming a turbine ring (1) and a ring support structure (3) comprising two annular flanges (32, 36), each ring sector (10) having two lugs (14, 15) held respectively between the two annular flanges (32, 36) of the ring support structure (3). The two annular flanges (32, 36) of the ring support structure (3) apply stress to the lugs (14, 16) of the ring sectors (10). One (36) of the flanges of the ring support structure (3) is elastically deformable in the axial direction (DA) of the turbine ring (1). The turbine ring assembly further comprises a plurality of stops (40; 41) engaged both in the annular flanges (32; 36) of the ring support structure (3) and the lugs (14; 16) of the ring sectors (10) facing the annular flanges (32; 36).