Turbine Ring Assembly Removable Flange Attachment
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Solution Overview
Problem
Existing turbine ring assemblies, particularly those using ceramic matrix composite (CMC) materials, face mechanical stress and vibration issues due to heat expansion of metal attachment parts, which can weaken the CMC ring sectors and compromise engine performance.
Innovation Solution
A turbine ring assembly design featuring a removable one-piece annular flange with attachment hooks and pegs that securely hold each ring sector in place, allowing for controlled deformation and improved sealing, while diverting high-pressure forces away from the CMC sectors, thus reducing mechanical stress and enhancing assembly efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If metal attachment parts are used to hold CMC ring sectors, then the assembly structure is simple and easy to manufacture, but the metal parts undergo heat expansion which mechanically stresses and weakens the CMC ring sectors
Solution Approach 1:
The invention divides the attachment system into separate functional elements: CMC attachment tabs integrated with the ring sector, metal attachment lugs on the support structure, and removable pegs as fastening elements. This segmentation allows each component to be optimized for its specific function while avoiding the heat expansion problem by not directly coupling metal attachment parts to the CMC sectors.
Solution Approach 2:
The invention introduces an intermediary fastening system using removable pegs that connect the CMC attachment tabs to the metal attachment lugs. This intermediary mechanism allows deterministic positioning and secure holding of CMC ring sectors without subjecting them to thermal stresses from metal expansion, as the pegs can be made of compatible materials and accommodate differential expansion.
2Temperature
If CMC ring sectors are used to reduce cooling flow and increase temperature, then engine performance is improved, but the CMC sectors are susceptible to mechanical stress from metal attachment part heat expansion
Solution Approach 1:
The attachment system is segmented into CMC tabs integrated with the high-temperature CMC sectors and separate metal lugs on the support structure, connected by removable pegs. This allows the CMC sectors to operate at high temperatures while the attachment mechanism is designed to accommodate thermal effects without transmitting stress to the CMC material.
Solution Approach 2:
The invention changes the attachment parameter from permanent metal-fastened connections to removable peg-based connections. This allows for controlled assembly and disassembly, and the pegs can be designed with appropriate material properties and geometric features (such as tapered shapes or compliance features) to accommodate thermal expansion differences while maintaining secure holding at operating temperatures.
3Ease of operation
If removable annular flange with attachment hooks is used, then assembly process is simplified and deterministic positioning is achieved, but the device complexity increases
Solution Approach 1:
The removable annular flange with integrated attachment hooks serves multiple functions: it provides deterministic positioning of CMC ring sectors during assembly, acts as a support structure for the attachment system, and enables easy assembly and disassembly of the turbine ring. By consolidating these functions into a single component, the overall device complexity is managed while achieving ease of operation.
Solution Approach 2:
The invention merges the annular flange structure with the attachment mechanism by integrating attachment hooks directly into the flange. This combination eliminates the need for separate positioning and attachment components, simplifying the assembly process while maintaining deterministic positioning. The unified structure reduces the number of parts compared to having separate positioning features and attachment mechanisms.
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, improves sealing, and simplifies the assembly process by allowing deterministic positioning and deformation of the ring sectors under temperature and pressure variations, independent of metal parts, while minimizing air leaks and assembly complexity.
Implementation Method 1
at least one attachment hook that protrudes from the second end of the annular flange and engages with at least one compartment included in the central annulus of the ring support structure in order to hold the annular flange in position
Implementation Method 2
allowing the ring sector, and by extension the ring, to deform under the effects of increases in temperature and variations in pressure
Implementation Method 3
deform under the effects of increases in temperature and variations in pressure
Data Source
AI summary
A turbine ring assembly includes ring sectors forming a turbine ring and a ring support structure, each ring sector having, in a section plane defined by an axial direction and a radial direction of the turbine ring, a portion forming an annular base with, in the radial direction, an inside face defining the inside face of the turbine ring and an outside face from which a first and a second attachment tab protrude, the ring support structure having a central annulus from which a first and a second radial tab protrude, between which the first and second attachment tabs of each ring sector are held. The first radial tab comprises a one-piece annular flange that is fastened in a removable manner to the central annulus of the ring support structure.