Interlocked Annular Seal Rings for Gas Turbine Leakage Control
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Solution Overview
Problem
Gas turbine engines face challenges in maintaining effective sealing between rotating components due to centrifugal forces and pressure differentials, leading to leakage and thermal asymmetry, which affects performance and durability.
Innovation Solution
An annular seal comprising first and second rings with split joints, slots, and tabs that interlock circumferentially, bridging gaps to prevent leakage, is designed to fit into an annular seal channel on a rotor shaft, utilizing a butt joint configuration and tapered tips for enhanced sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-piece annular seal is used, then sealing effectiveness is improved, but manufacturing complexity and assembly difficulty increase
Solution Approach 1:
The annular seal is divided into multiple segments (first annular segment, second annular segment, third annular segment) that can be manufactured separately and then assembled together. Each segment contains sealing surfaces and can be independently fabricated, reducing manufacturing complexity while maintaining the overall sealing effectiveness of the complete seal structure.
2Ease of manufacture
If a segmented seal structure is used, then manufacturing and assembly ease are improved, but sealing effectiveness deteriorates due to gaps at joints
Solution Approach 1:
The sealing segments are designed with nested or interlocking features where the third annular segment fits within or alongside the first and second segments. This nesting arrangement allows the segments to be manufactured separately for ease of production while the interlocking geometry ensures continuous sealing contact, preventing leakage at the joints and maintaining overall sealing effectiveness.
3Reliability
If seal rings are made as continuous circles, then sealing performance is improved, but installation difficulty increases due to inability to expand
Solution Approach 1:
The seal rings are segmented into multiple adjustable sections rather than continuous circles. This segmentation allows each section to be independently positioned and the entire seal assembly to be expanded or contracted during installation by adjusting the relative positions of segments, facilitating easier installation while maintaining sealing performance through the coordinated arrangement of sealing surfaces across segments.
4Ease of manufacture
If seal segments are positioned adjacently, then assembly simplicity is improved, but leakage risk increases at the joints
Solution Approach 1:
The seal segments are designed with asymmetric geometries where the sealing surfaces are not uniformly distributed but positioned at specific asymmetric locations. This asymmetric design creates overlapping or interlocking sealing zones at the joints between segments, preventing leakage paths while maintaining simple adjacent positioning for easy assembly. The asymmetric features ensure that gaps at joints are minimized or eliminated through the specific geometric relationships between segments.
Data Source
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AI summary
A gas turbine engine (20) includes a rotor (62) that has a seal surface (68) and a shaft (70) that is rotatable about an engine central axis (A). The shaft has an annular seal channel (72) that opens to the seal surface. An annular seal (74) is insertable into the annular seal channel for sealing against the seal surface. The annular seal is comprised of first and second rings (76, 78) that each have a split joint (80), a slot (82) radially adjacent the split joint, and a tab (84) that projects into the slot of the other of the first or second rings such that the first and second rings are circumferentially interlocked.