Multi-stage Inter Shaft Ring Seal with Overlapping Protrusions
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Solution Overview
Problem
Current carbon ring seals in high-performance engines face challenges in wear resistance and reliability due to aggressive cost, weight, size, and reliability metrics, with existing designs requiring relief cut notches that can lead to improper assembly and increased wear on certain stages, compromising performance and reliability.
Innovation Solution
A multi-stage inter shaft ring seal design with overlapping 'fool-proofing' geometry and protrusions that eliminate the inner diameter relief cut notch on stages that do not require it, providing additional contact area and reducing contact pressure and PV levels, while ensuring proper assembly through unique geometry constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If relief cut notches are provided on all carbon ring stages to avoid seal plate radius edges, then improper assembly is prevented, but contact pressure and PV levels increase on stages that do not require the notch
Solution Approach 1:
The relief cut notch is selectively applied only to carbon ring stages (2, 4, and 6) that require it to avoid seal plate radius edges, while stages (1, 3, and 5) that do not require the notch are left without it. This local differentiation optimizes each stage's performance by eliminating unnecessary notches that would increase contact pressure and PV levels, while maintaining assembly fool-proofing where needed.
2Stress or pressure
If relief cut notches are removed from stages that do not require them, then contact pressure and PV levels are reduced, but assembly fool-proofing is compromised
Solution Approach 1:
The carbon ring stages are designed with asymmetric features: stages 2, 4, and 6 have relief cut notches while stages 1, 3, and 5 do not. This asymmetry creates inherent fool-proofing that prevents improper assembly, as each stage's unique geometry ensures it can only be installed in the correct position. The asymmetric design maintains reliability while optimizing contact pressure and PV levels by eliminating unnecessary notches.
3Reliability
If carbon ring stages are made different from each other to provide fool-proofing, then improper assembly is prevented, but manufacturing complexity increases
Solution Approach 1:
The seal system is segmented into six distinct carbon ring stages, with relief cut notches selectively applied to specific stages (2, 4, and 6) that require them. This segmentation approach provides fool-proofing through localized geometric differences rather than requiring all stages to be completely different, thereby reducing manufacturing complexity while maintaining reliability.
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 solution enhances wear resistance, reliability, and assembly fool-proofing, reducing carbon ring wear and failure, and improves cost and quality metrics by optimizing contact pressure and PV levels, thus meeting the demands of next-generation engines.
Implementation Method 1
a spring located in a cavity formed between the first seal and the second seal
Data Source
AI summary
Aspects of the disclosure are directed to a system comprising: a first seal that includes a notch configured to avoid an adjacent seal plate radius edge and a first protrusion, and a second seal that is notch-free with respect to an inner diameter sealing face and includes a second protrusion, wherein the first protrusion and the second protrusion are configured to at least partially overlap with one another in at least one of an axial direction or a radial direction with respect to an engine centerline.