Multi-Piece Ring Seal Assembly for Compressor 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 seal is used to prevent leakage between compressor stages, then engine efficiency is improved, but the seal complexity and manufacturing difficulty increase
Solution Approach 1:
The seal is divided into multiple segments or pieces that can be assembled together to form a complete sealing structure. This segmentation allows for easier manufacturing and assembly while maintaining effective sealing between compressor stages, reducing both manufacturing complexity and leakage losses.
Solution Approach 2:
The multi-piece seal assembly is nested within the compressor stage structure, with seal segments fitting within designated channels or grooves. This nesting approach integrates the sealing function into the existing compressor architecture without adding significant external complexity.
2Productivity
If a multi-piece seal assembly is used to reduce leakage, then thermal and propulsive efficiencies are enhanced, but the manufacturing precision requirements increase
Solution Approach 1:
By segmenting the seal into multiple pieces, each individual segment can be manufactured with standard precision tolerances, and the cumulative sealing effect is achieved through proper assembly. This reduces the overall manufacturing precision requirements compared to a single-piece seal requiring high precision throughout.
Solution Approach 2:
The seal segments act as intermediaries between the rotating shaft and the stationary compressor housing, creating sealing interfaces at multiple locations. This distributed sealing approach reduces the precision burden on any single interface while maintaining overall sealing effectiveness.
3Reliability
If angled guide surfaces are used to generate biasing forces during rotation, then seal effectiveness is improved, but the device complexity increases
Solution Approach 1:
The angled guide surfaces are designed to utilize the dynamic rotational motion of the shaft to generate centrifugal forces that press the seal segments against the mating surfaces. This dynamic sealing mechanism improves reliability during operation while adding minimal static complexity to the seal structure.
Solution Approach 2:
The seal assembly uses its own rotational motion to generate the necessary biasing forces through the angled guide surfaces. The centrifugal force generated during rotation automatically presses the seal segments against the sealing surfaces, eliminating the need for external actuation mechanisms or additional complexity.
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 the thermal, transfer, and propulsive efficiencies of the gas turbine engine by utilizing centrifugal forces and angled guide surfaces to maintain seals.
Implementation Method 1
utilizing centrifugal forces and angled guide surfaces to maintain seals
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A rotor assembly for a gas turbine engine (20) includes a shaft (70) co-rotatable with a rotor (62) with an annular seal assembly (74) that is carried within an annular channel (72) within the shaft (70) that provides a seal between the shaft (70) and the bore (68). The annular seal assembly (74) includes a first member (76) that is configured to seal against a radial surface of the bore (68) and a second member (78) that is configured to seal against an axial surface of the annular channel (72).