Segmented Turbine Shroud With Movable Attachment Features
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Solution Overview
Problem
Gas turbine engines face performance losses due to gas leakage through static shrouds, which reduces the efficiency of work extraction by turbine blades, and existing shroud designs are complex and difficult to assemble.
Innovation Solution
A segmented turbine shroud design featuring a carrier segment with a radially inwardly-opening cavity, a blade track segment made of ceramic-containing materials, and a track attachment system that includes positioner and retainer posts with L-shaped cross-sectional profiles, allowing for axial movement and engagement to block radial movement of the blade track segment, enhancing sealing and assembly efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a segmented turbine shroud design is used, then sealing efficiency is improved and gas leakage is reduced, but device complexity increases due to multiple components requiring assembly
Solution Approach 1:
The turbine shroud is divided into multiple segments (carrier segment, blade track segment, seal segment) that can be assembled separately and then joined together. This segmentation allows for improved sealing at the interfaces between segments while maintaining the overall shroud structure, directly addressing the gas leakage problem without requiring a complete redesign of the entire shroud as a single complex piece.
Solution Approach 2:
The seal segment is positioned within the cavity formed by the carrier segment and blade track segment, with the seal extending into the gap between these segments. This nested arrangement allows the seal to effectively block gas leakage paths at the segment interfaces while being contained within the overall shroud structure, improving sealing efficiency without adding external complexity.
2Manufacturing precision
If a track attachment system with positioner and retainer posts is used, then manufacturing precision is improved for positioning the blade track segment, but device complexity increases due to additional attachment components
Solution Approach 1:
The positioner post is designed with a positioner attachment feature that protrudes into the cavity before final assembly, pre-establishing the correct positional relationship between the carrier segment and blade track segment. This preliminary positioning action ensures manufacturing precision is maintained during assembly without requiring complex adjustment mechanisms or post-assembly calibration.
Solution Approach 2:
The retainer post features a retainer attachment feature with an L-shaped cross-section that automatically engages with the carrier segment cavity during assembly. The L-shaped geometry provides self-aligning and self-locking capabilities, where the attachment feature itself performs the positioning and securing functions without requiring additional fasteners or complex retention mechanisms, thereby maintaining precision while limiting complexity growth.
3Reliability
If ceramic-containing materials are used for the blade track segment, then reliability is improved due to high-temperature resistance, but ease of manufacture is reduced due to difficulty in working with ceramic materials
Solution Approach 1:
The blade track segment is constructed using ceramic-containing materials that provide high-temperature resistance and reliability in the turbine environment. By accepting the manufacturing challenges of ceramic materials and incorporating them into the blade track segment where their thermal properties are most beneficial, the design achieves improved reliability while the segmented structure allows for specialized manufacturing techniques to be applied to each segment separately, mitigating some of the ease of manufacture concerns.
Data Source
AI summary
A turbine shroud for positioning radially outside of blades of a turbine rotor includes a carrier, a blade track, and a track attachment system. The blade track is moved radially outwardly into a cavity of the carrier, and the track attachment system is adjusted to block radially inward movement of the blade track out of the cavity.