Multi-Piece Ring Seal for Compressor Stage Leakage Control
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Solution Overview
Problem
Leakage past seals in the compressor section of gas turbine engines affects engine efficiency, and there is a need for improved thermal, transfer, and propulsive efficiencies.
Innovation Solution
A rotor assembly with an annular seal assembly that includes a first member configured to seal against a radial surface and a second member configured to seal against an axial surface, utilizing guide surfaces and guided surfaces to generate seals and biasing forces during rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a single-piece seal is used between the shaft and bore, then the seal structure is simple, but leakage occurs between compressor stages reducing efficiency
Solution Approach 1:
The seal assembly is divided into multiple independent members: a first seal member that seals against the radial surface of the bore, and a second seal member that seals against the axial surface of the annular channel. This segmentation allows each member to specialize in sealing a specific direction, effectively preventing leakage while maintaining manageable structural complexity
Solution Approach 2:
The second seal member acts as an intermediary element that seals the axial gap between the first seal member and the annular channel, preventing leakage paths that would otherwise exist between the primary sealing surfaces. This intermediary sealing approach comprehensively blocks leakage routes
2Reliability
If seal members are made larger to improve sealing, then sealing effectiveness increases, but the seal assembly complexity and manufacturing difficulty increase
Solution Approach 1:
By segmenting the seal into multiple smaller members with specific functions (radial sealing vs. axial sealing), each member can be manufactured independently with simpler geometry and tighter tolerances, improving ease of manufacture while collectively achieving high sealing effectiveness
Solution Approach 2:
Each seal member is designed with local quality optimized for its specific sealing function: the first seal member has properties optimized for radial sealing against the bore, while the second seal member has properties optimized for axial sealing against the annular channel, achieving high reliability without requiring all members to be oversized
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 annular seal assembly effectively reduces leakage between compressor stages, enhancing compressor and engine efficiencies by utilizing centrifugal forces to maintain seals against both radial and axial surfaces.
Implementation Method 1
the interface between the guide surface and the guided surface is configured to generate a biasing force against the first member in response to rotation of the shaft and rotor
Data Source
AI summary
A rotor assembly for a gas turbine engine includes a shaft co-rotatable with a rotor with an annular seal assembly that is carried within an annular channel within the shaft that provides a seal between the shaft and the bore. The annular seal assembly includes a first member that is configured to seal against a radial surface of the bore and a second member that is configured to seal against an axial surface of the annular channel.