Segmented Carbon Seal Channels for Oil Leakage and Wear Balance
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Solution Overview
Problem
Existing seal systems in gas turbine engines face challenges in effectively isolating oil-containing bearing compartments, particularly in reducing oil leakage and maintaining pressure differences across seals, which can lead to wear and reduced buffering efficiency.
Innovation Solution
A segmented seal system with arcuate body segments featuring circumferential channels and dams, where the ID face channel has an open end and is deeper and wider than the OD face channel, allowing for optimized pressure distribution and airflow, reducing wear and enhancing structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If circumferential grooves are provided on seal faces to reduce contact forces and wear, then wear is reduced, but oil leakage increases due to disrupted pressure distribution
Solution Approach 1:
The seal is divided into multiple circumferential segments with gaps between them, allowing the seal to flex and conform to the mating surface while maintaining sealing effectiveness. The segmentation enables the seal to accommodate wear and deformation without complete failure, addressing the contradiction between wear reduction and leakage prevention.
Solution Approach 2:
The seal incorporates circumferential grooves only in specific locations on the seal face, rather than uniformly across the entire surface. This localized groove configuration reduces contact forces and wear in high-stress areas while preserving pressure distribution and sealing capability in critical sealing zones, thus balancing wear reduction with leakage control.
2Loss of substance
If buffer air pressure is increased to limit oil leakage, then oil containment improves, but seal wear increases due to higher contact loads
Solution Approach 1:
The seal incorporates elastic segments that can dynamically adjust their contact pressure with the mating surface. When buffer air pressure increases, the elastic segments deform to distribute the increased contact loads more uniformly, preventing localized overheating and wear while maintaining the higher pressure needed for oil containment.
Solution Approach 2:
The seal uses flexible elastic segments rather than rigid materials, allowing the seal to conform to the mating surface and distribute contact pressures. This flexibility enables the seal to withstand higher buffer air pressures for improved oil containment without experiencing excessive contact loads that would lead to premature wear.
3Stress or pressure
If multiple circumferential grooves are added to distribute pressure, then pressure distribution improves, but structural integrity decreases
Solution Approach 1:
The seal is divided into multiple independent circumferential segments rather than using continuous grooves. This segmentation provides structural reinforcement between the gaps, maintaining overall seal integrity while still allowing pressure distribution across the seal face. The segmented structure prevents the grooves from compromising structural strength.
Solution Approach 2:
The seal combines elastic material with a reinforcing structure, creating a composite that provides both the flexibility needed for pressure distribution and the structural integrity required to maintain seal strength. The composite construction allows multiple circumferential features without sacrificing overall structural performance.
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 segmented seal system effectively minimizes oil leakage, maintains pressure differences, and tolerates wear by shifting pressure drops to reduce adverse contact loads, ensuring efficient oil containment and prolonged seal performance.
Implementation Method 1
a plurality of elastic seal segments
Implementation Method 2
the compartments are at a lower pressure than the pressurized spaces
Data Source
AI summary
A seal segment has an arcuate body having: a first end; a second end circumferentially opposite the first end; a first face; a second face axially opposite the first face; an inner diameter (ID) face; and an outer diameter (OD) face. The seal segment is shaped to interfit with a plurality of identical seal segments first end to second end to form a seal surrounding a central longitudinal axis. The first face has: a circumferential channel closer to the ID face than the OD face; and a plurality of channels extending from the circumferential channel to the OD face. The ID face has: a circumferential channel closer to the first face than the second face; and a plurality of channels extending from the circumferential channel to the second face. The ID face circumferential channel has an open end.