Turbine Engine Seal Assembly for Low-Friction Rotor Tracking
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Solution Overview
Problem
Existing seal assemblies in gas turbine engines face challenges in managing large radial gaps between rotor and stator components, leading to high friction and potential seal failure due to large seal differential pressure and fence height, which affects operational efficiency.
Innovation Solution
A seal assembly with segmented seal segments and a biasing member, featuring a stator design with recesses or fluid channels that create intermediate pressure regions, providing an aft-to-forward axial force to reduce friction between seal segments and the stator, minimizing interference and enhancing dynamic tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If seal assemblies are used to reduce radial gap flow leakage, then sealing effectiveness is improved, but friction between seal segments and stator increases leading to potential seal failure
Solution Approach 1:
The seal assembly is divided into multiple seal segments that can independently deflect and track rotor excursions. This segmentation allows each segment to adapt to rotor movements while maintaining sealing contact, reducing overall friction compared to a single rigid seal structure.
Solution Approach 2:
The seal segments are designed to be dynamic rather than static, allowing them to deflect and follow rotor excursions. The biasing member provides continuous contact force while the segments can move dynamically to accommodate rotor movements, maintaining sealing effectiveness while reducing friction through adaptive positioning.
2Reliability
If seal segments are designed to maintain continuous contact with rotor for sealing, then sealing effectiveness is improved, but axial loads on seal segments increase
Solution Approach 1:
By dividing the seal into multiple segments, the total axial load is distributed across several individual segments rather than concentrated on a single seal structure. Each segment carries a portion of the axial load, reducing the burden on any single component while maintaining overall sealing effectiveness.
Solution Approach 2:
The biasing member acts as an intermediary that provides the necessary contact force between the seal segments and the rotor. It delivers axial loading in a controlled manner, ensuring continuous contact for sealing while managing the magnitude and distribution of axial forces to prevent overload.
3Ease of manufacture
If radial gap between rotor and stator is increased, then manufacturing and assembly tolerance is improved, but flow leakage increases
Solution Approach 1:
The seal segments are designed to dynamically deflect and follow rotor excursions, maintaining effective sealing contact despite variations in radial gap size. This dynamic adaptation allows the seal to function effectively with larger radial gaps that are easier to manufacture and assemble, while preventing excessive flow leakage.
Solution Approach 2:
The seal design changes the operational parameters by allowing the seal segments to deflect through specific ranges to accommodate radial gap variations. By designing for controlled deflection parameters, the system can tolerate larger radial gaps for easier manufacturing while maintaining sealing effectiveness through the deflection mechanism.
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 effectively reduces friction and maintains seal integrity by minimizing axial loads, allowing the seal segments to dynamically track rotor excursions, thereby improving operational reliability and efficiency.
Implementation Method 1
pressurized fluid engaging with the at least one feature provides an aft-to-forward axial force that reduces friction between interfacing aft surfaces of the plurality of seal segments and the stator
Data Source
AI summary
A seal assembly includes a plurality of seal segments for sealing between a rotor and a stator, wherein, when arranged together, the rotor, the stator, and the plurality of seal segments define a high pressure region and a low pressure region. The seal assembly further includes a biasing member engaged with the plurality of seal segments and at least one feature formed in the stator. As such pressurized fluid engaging with the at least one feature provides an aft-to-forward axial force that reduces friction between interfacing aft surfaces of the plurality of seal segments and the stator.