Floating Labyrinth Seal Assembly for Variable Radial Clearance
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Solution Overview
Problem
Labyrinth seals in engines face challenges due to varying radial clearance, which affects sealing efficiency and leads to leakage and wear, especially under conditions of vibration, deflection, and thermal growth.
Innovation Solution
A labyrinth seal assembly comprising an outer seal component, a floating seal component, and an inner seal component with radially extending teeth, allowing for radial movement and rotational coupling, while anti-rotational features prevent unwanted rotation, and a biasing element ensures axial loading for improved sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the radial clearance is reduced to improve sealing efficiency, then leakage decreases, but wear increases due to contact between seal components and rotating shaft
Solution Approach 1:
The seal component is designed to float radially on the rotating shaft, allowing dynamic adjustment of the radial clearance. The seal can move radially in response to vibration, deflection, and thermal growth, maintaining optimal clearance without contact wear. This dynamic capability resolves the contradiction by enabling the seal to adapt its position rather than being fixed at a constant small clearance that would cause wear.
2Reliability
If the radial clearance is increased to reduce wear, then sealing efficiency deteriorates and leakage increases
Solution Approach 1:
The floating seal design allows the seal to dynamically adjust its radial position based on operating conditions. During normal operation, the seal maintains a small clearance for good sealing. When vibration or deflection occurs, the seal can move radially outward to prevent contact and wear, then return to its sealing position when conditions normalize. This dynamic behavior resolves the contradiction between wear reduction and sealing efficiency.
3Stability of the object's composition
If the seal is made fixed to improve sealing stability, then adaptability to vibration and thermal growth decreases
Solution Approach 1:
The seal is designed with radial floating capability while maintaining axial stability through the bearing support. The seal can move radially to adapt to vibration, deflection, and thermal growth, but remains axially positioned to maintain sealing stability. This dynamic radial freedom with axial constraint resolves the contradiction between stability and adaptability.
4Adaptability or versatility
If the radial clearance varies during operation, then adaptability to thermal growth improves, but sealing efficiency deteriorates
Solution Approach 1:
The floating seal design allows the seal to dynamically adjust its radial position in response to thermal growth and other operational variations. The seal maintains optimal clearance by moving with the shaft, preventing both contact wear and excessive leakage. This dynamic adjustment resolves the contradiction by enabling the seal to adapt to thermal growth while maintaining sealing efficiency through continuous position optimization.
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 seal assembly effectively minimizes radial clearance, reduces leakage, and mitigates wear by allowing the seal to float radially with the shaft, maintaining efficient sealing under varying conditions and improving engine performance.
Implementation Method 1
an axial seal surface facing away from the axial location and bearing against the axial housing surface
Implementation Method 2
the seal movable in the radial direction relative to the housing unhindered by the first anti-rotational feature
Data Source
Figure 1
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AI summary
A labyrinth seal assembly (30) comprises an outer seal (60) having a radially inner cavity surface (42), and an axial cavity surface (44) inward of the radially inner cavity surface (42), a floating seal (50) received by the outer seal (60) so as to be movable in a radial direction relative to the outer seal (60), the floating seal (50) having a radially outer seal surface (52) spaced inwardly from the radially inner cavity surface (42), a radially inner surface (56) inward of the radially outer seal surface (52), and an axial seal surface (54) bearing against the axial cavity surface (44), and an inner seal (20, 60) received by the floating seal (50), the inner seal (20, 60) having a radially outer surface (62) spaced inwardly from the radially inner surface (56). A first one of the radially outer surface (62) and the radially inner surface (56) defines one tooth (34) projecting toward a second one of the radially outer surface (62) and the radially inner surface (56) to inward of the axial seal surface (54).