Split-Hoop Sliding Seal With Spring Tabs for High-Deflection Sealing
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Solution Overview
Problem
Conventional seals used in gas turbine engines, such as metal w-seals and non-metallic rope seals, fail prematurely due to significant relative deflections and elevated temperatures, leading to inefficiencies in engine performance and component life, with limited flexibility and wear resistance.
Innovation Solution
A split-hoop seal design comprising a first seal section with a smaller inner diameter for radial preload and a second seal section with frustoconically extending spring tabs, made from high-temperature materials, which are integrally formed and configured to axially load the first seal section, providing improved sealing and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a metal w-seal is used to seal the gas path, then the seal can accommodate some relative deflection, but it deforms and becomes ineffective under significant deflections
Solution Approach 1:
The seal is divided into multiple segments or lips that can independently deflect and conform to the mating surface. This segmentation allows the seal to accommodate significant relative deflections while maintaining continuous contact and sealing effectiveness, as each segment can adapt to the deflection without compromising the overall seal integrity.
Solution Approach 2:
The seal design incorporates variable cross-sectional geometry along its length, with different segments having different stiffness characteristics. This parameter variation allows the seal to be flexible where needed while maintaining structural integrity, enabling it to handle significant deflections without deformation that would compromise sealing.
2Strength
If a higher strength material is used to improve deflection capability, then the seal can withstand greater deflections, but the temperature capability is limited
Solution Approach 1:
The seal employs composite construction combining materials with complementary properties - typically a high-temperature resistant base material (such as ceramic matrix composite or high-temperature alloy) with reinforcement elements or coating layers that provide enhanced strength and deflection capability. This composite approach allows the seal to withstand both high temperatures and significant deflections simultaneously.
Solution Approach 2:
Different regions of the seal are made from materials or have properties optimized for their specific functions - the contact surfaces use materials with high wear and temperature resistance, while internal structures use materials optimized for strength and flexibility. This local differentiation allows the seal to achieve high temperature capability in critical areas while maintaining overall deflection resistance.
3Temperature
If a rope seal is used to achieve high temperature capability, then the seal can withstand elevated temperatures, but it has even less flexibility
Solution Approach 1:
The rope seal design is segmented into multiple flexible elements or strands that can independently bend and conform to deflections. This segmentation maintains the high-temperature capability of the rope material while restoring flexibility, as each small segment can adapt to deflections without requiring the entire seal to be highly flexible.
Solution Approach 2:
The seal incorporates dynamic characteristics that allow it to adapt its flexibility based on operating conditions - under normal conditions it maintains structural rigidity for high-temperature resistance, but under deflection it can dynamically adjust its shape through the movement of segmented elements, providing the needed flexibility without compromising temperature capability.
4Strength
If a seal is designed for high strength and temperature resistance, then it can withstand harsh conditions, but wear resistance becomes a problem under significant relative motion
Solution Approach 1:
The seal features locally optimized surfaces with different properties - the bulk material provides high-temperature strength while the contact surfaces are treated or coated with wear-resistant materials. This local differentiation allows the seal to maintain temperature resistance in the structure while providing enhanced wear resistance at the critical contact interfaces where relative motion occurs.
Solution Approach 2:
The seal design incorporates preliminary wear protection through surface treatments, coatings, or sacrificial layers applied during manufacturing. These preliminary protective measures are built into the seal structure before installation, providing immediate wear resistance at contact surfaces while the main body material maintains its high-temperature strength characteristics.
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 split-hoop seal design enhances durability and temperature capability, maintaining effective sealing during relative movement of components, reducing wear and deformation, and ensuring robust performance under varying conditions.
Implementation Method 1
a second seal section with frustoconically extending spring tabs, made from high-temperature materials, which are integrally formed and configured to axially load the first seal section
Data Source
AI summary
The present disclosure relates generally to a sliding seal between two components. The sliding seal includes a first seal section and an uncoupled second seal section which allows the first and second seal sections to move relative to one another during relative movement between the two components. One or more spring tabs extend from the second seal section and bias the first and second seal sections away from one another.