Turbine Shroud Strip Seal Assembly for Leakage and Flutter Damping
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Solution Overview
Problem
Existing turbine shroud assemblies suffer from inefficiencies in sealing elements, leading to air leakage and fluttering movements, which can reduce the life and efficiency of the strip seal assemblies, and thus, reduce the possibility of failure.
Innovation Solution
A damping strip seal assembly is used to include a first shroud segment, a second shroud segment, and a damping strip seal assembly, which contact with the outer case 17 with hook features in the illustrative embodiment. The damping strip seal assembly includes a damping segment 46 that urges the damping strip seal assembly 30 radially inward as suggested in FIG. 3.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional sealing elements are used between shroud segments, then the structure is simple, but air leakage occurs and fluttering movements reduce the life and efficiency of the strip seal assemblies
Solution Approach 1:
The damping segment is integrated with the strip seal assembly to form a unified structure. The damping segment includes a leading edge portion that contacts the blade track and a trailing edge portion that contacts the shroud segment, merging sealing and damping functions into a single component that improves reliability without proportionally increasing complexity
Solution Approach 2:
The damping segment is formed from a material with damping characteristics that differ from the strip seal material. This composite approach allows the leading edge portion to provide sealing while the trailing edge portion provides flutter damping, resolving the contradiction between reliability and structural simplicity
2Loss of energy
If sealing elements are added to block air leakage between segments, then air leakage is reduced, but fluttering movements and vibration increase, reducing the life of the assembly
Solution Approach 1:
The damping segment is designed with different portions having different functions: the leading edge portion provides sealing contact with the blade track to prevent air leakage, while the trailing edge portion provides flutter damping contact with the shroud segment. This local differentiation resolves the contradiction by addressing both air leakage and fluttering in specific zones of the same component
Solution Approach 2:
The damping segment acts as an intermediary element between the strip seal assembly and the shroud segment. It mediates the interaction by providing both sealing contact and flutter damping contact, allowing the system to block air leakage while simultaneously reducing fluttering movements that would otherwise reduce assembly life
3Stability of the object's composition
If the strip seal assembly is made more rigid to prevent fluttering, then fluttering is reduced, but the ability to seal effectively against the blade track decreases
Solution Approach 1:
The sealing system is segmented into distinct functional portions: the strip seal assembly provides sealing contact with the blade track, while the separate damping segment provides flutter resistance by contacting the shroud segment. This segmentation allows each component to be optimized for its specific function without compromising the other, resolving the contradiction between rigidity for flutter resistance and flexibility for sealing effectiveness
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 damping strip seal assembly effectively minimizes fluttering and vibration, thereby enhancing the durability and performance of the turbine shroud assembly by dampening any flutter or vibration during operation.
Implementation Method 1
The damping segment may engage the body segment and at least one of the first flange, the second flange, the third flange, and the fourth flange to urge the body segment of the damping strip seal assembly radially inward against the first blade track segment and the second blade track segment to dampen flutter movement of the body segment
Data Source
AI summary
A turbine shroud assembly for use with a gas turbine engine includes a first shroud segment, a second shroud segment, and a damping strip seal assembly. The first shroud segment has a first carrier segment arranged circumferentially at least partway around a central axis and a first blade track segment supported by the first carrier segment. The second shroud segment is arranged circumferentially adjacent the first shroud segment. The damping strip seal assembly includes a body segment and a damping segment that extends along a curvilinear path.