Turbine Ring Sector Sealing via Segmented Annular Flanges
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Solution Overview
Problem
Turbine ring assemblies using ceramic matrix composite (CMC) materials face mechanical stress and weakening due to hot expansion of metal attachment parts, which can lead to vibration and compromised sealing, especially under temperature and pressure variations.
Innovation Solution
A turbine ring assembly design featuring two annular flanges with a contact stop, where the second annular flange absorbs high-pressure distributor forces directly into the ring support structure, avoiding transmission through the CMC ring, and a flexible upstream flange configuration to prevent tilting and maintain deterministic sector positioning, enhancing sealing and reducing assembly complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If metal attachment parts are used to connect CMC ring sectors, then the assembly can be manufactured with conventional materials, but the metal parts undergo hot expansion which causes mechanical stress and embrittlement of the CMC ring sectors
Solution Approach 1:
The first annular flange is segmented into multiple detachable segments that can be independently positioned and installed. This segmentation allows the flange to adapt to thermal expansion of metal parts while maintaining secure connection to CMC ring sectors, reducing mechanical stress on the brittle CMC material during assembly and operation.
Solution Approach 2:
The detachable segment design enables dynamic adjustment of the flange configuration in response to thermal conditions. The segments can be positioned to accommodate expansion gaps that occur during turbine operation, preventing stress concentration and embrittlement of the CMC ring sectors while maintaining structural integrity.
2Stability of the object's composition
If the turbine ring assembly allows deformation under temperature and pressure variations, then the CMC ring sectors can maintain their mechanical properties, but the sealing between sectors may be compromised
Solution Approach 1:
The detachable segments are pre-configured with positioning features and sealing surfaces that ensure proper alignment and sealing before the turbine operates. This preliminary arrangement guarantees that even when thermal expansion occurs during operation, the segments remain properly positioned to maintain sealing effectiveness between CMC ring sectors.
Solution Approach 2:
The first annular flange acts as an intermediary element between the CMC ring sectors and the turbine casing. Its detachable segment design allows it to mediate the thermal expansion effects, absorbing dimensional changes while maintaining continuous sealing contact with the CMC sectors, thus protecting the sectors from stress while ensuring reliable sealing.
3Manufacturing precision
If a rigid flange structure is used to hold ring sectors in position, then deterministic positioning is achieved, but the assembly cannot accommodate thermal expansion independently of metal parts
Solution Approach 1:
Dividing the annular flange into detachable segments provides both precise positioning capability and thermal adaptability. Each segment can be individually positioned to achieve deterministic alignment of CMC ring sectors during assembly, while the segmented structure allows for controlled movement and gap adjustment during thermal expansion, combining precision with adaptability.
Solution Approach 2:
The detachable segment configuration transitions from a static rigid structure to a dynamic system that can adapt to thermal conditions. The segments maintain precise positioning through their designed connection features while allowing controlled relative movement to accommodate expansion, enabling the assembly to adapt to temperature variations without compromising positioning accuracy.
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 reduces mechanical stress on CMC ring sectors, maintains deterministic positioning, improves sealing between sectors, and simplifies assembly by allowing deformation independent of metal parts, while controlling axial forces and ensuring consistent sealing.
Implementation Method 1
The second annular flange upstream of the turbine ring and free from any contact with the ring is configured to transmit the maximum axial force induced by the HPD directly into the ring support structure without passing through the ring
Implementation Method 2
a flexible upstream flange configuration to prevent tilting and maintain deterministic sector positioning
Data Source
Figure 1
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AI summary
A turbine ring assembly comprising ring sectors (10) forming a turbine ring (1) and a ring support structure (3), each ring sector (10) having, in a plane of section defined by an axial direction (DA) and a radial direction (DR) of the ring (1), a portion forming an annular base (12) with, in the radial direction (DR), an internal face (12a) defining the internal face of the ring (1) and an external face (12b) from which there extend in projection a first and a second securing tab (14, 16), said structure (3) comprising a central shell (31) from which there extend in projection a first and a second a first and a second radial flange (32, 36), the first and second securing tabs (14, 16) of each ring sector (10) being held between said flanges. It comprises a first and a second annular flange (33, 34) that are removably attached to the first radial flange (32) of the central shell (31) and are separated from one another by a contact abutment (330, 340).