Resilient Seal Runner for Stable Turbine Engine Gap Sealing
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Solution Overview
Problem
Gas turbine engines face challenges in maintaining the dimension of controlled gap seals between rotating and static parts due to thermal growth and centrifugal forces, leading to decreased sealing efficiency and potential lubricant leakage.
Innovation Solution
A resiliently deformable seal runner is used, which changes shape from an at-rest to a pre-loaded configuration under axial compression, increasing its outer diameter and maintaining a consistent gap height despite thermal growth and centrifugal forces, by adjusting its curvature and axial width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a controlled gap seal is used between rotating and static parts, then sealing efficiency is improved, but thermal growth and centrifugal force cause dimensional changes in the gap that decrease sealing efficiency
Solution Approach 1:
The seal runner is designed with resiliently deformable material that allows it to dynamically adjust its outer diameter in response to changing operating conditions. The seal runner transitions from a rigid dimensional structure to a dynamically adaptive structure that can change its gap dimension with temperature and centrifugal force variations, thereby maintaining sealing efficiency throughout the operating range.
Solution Approach 2:
The seal runner's outer diameter parameter is made variable through the use of resiliently deformable material. As temperature increases and centrifugal force acts on the rotating seal runner, the material's dimensional parameters change automatically, allowing the gap dimension to be adjusted in real-time to compensate for thermal growth and maintain consistent sealing performance.
2Manufacturing precision
If the seal runner is made rigid to maintain gap dimension, then manufacturing precision is improved, but adaptability to thermal growth and centrifugal force is reduced
Solution Approach 1:
The seal runner is constructed from resiliently deformable material that functions as a flexible component within the sealing system. This flexible structure allows the seal runner to bend and deform radially in response to thermal and centrifugal loads, providing adaptability to operating conditions while maintaining precise gap control through elastic deformation rather than rigid structural changes.
Solution Approach 2:
The use of resiliently deformable material represents a composite or specially engineered material solution that combines the necessary structural integrity with controlled flexibility. This material enables the seal runner to maintain manufacturing precision at rest while adapting to operating conditions through predictable elastic deformation, effectively merging the benefits of both rigid precision and flexible adaptability.
3Reliability
If axial compression force is applied to pre-load the seal runner, then sealing contact is improved, but the seal runner shape changes affecting the gap dimension
Solution Approach 1:
The seal runner is pre-loaded with axial compression force during assembly to establish initial contact and sealing pressure before operation. This preliminary action ensures that the seal runner is already engaged with the sealing surface when the engine starts, providing immediate sealing protection. The resiliently deformable material allows this pre-loading without permanent deformation, enabling the seal to maintain contact under varying operating conditions.
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
This solution effectively compensates for dimensional changes caused by thermal growth and centrifugal forces, maintaining sealing efficiency and preventing lubricant leakage across varying operating conditions.
Implementation Method 1
the seal runner resiliently deformable from an at-rest shape where no axial compression force is exerted on the seal runner to a pre-loaded shape where the seal runner is axially clamped on the shaft by an axial compression force
Implementation Method 2
thermal growth and centrifugal force affect a dimension of this controlled gap, which may results in a decrease of the sealing efficiency in some conditions
Implementation Method 3
thermal growth and centrifugal force affect a dimension of this controlled gap
Data Source
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AI summary
An aircraft engine (10), has: a shaft (20) rotatable about a central axis (11); a housing (32) mounted around the shaft (20); and a seal assembly (40) disposed radially between the shaft (20) and the housing (32) relative to the central axis (11), the seal assembly (40) having: a sealing ring (42) mounted to the housing (32), and a seal runner (50) secured to the shaft (20), the seal runner (50) extending radially relative to the central axis (11) from an inner face (50I) facing the shaft (20) to an outer face (50O) facing the sealing ring (42) and being radially spaced apart from the sealing ring (42) by a gap (G), the seal runner (50) resiliently deformable from an at-rest shape where no axial compression force is exerted on the seal runner (50) to a pre-loaded shape where the seal runner (50) is axially clamped on the shaft (20) by an axial compression force, an outer diameter (D) of the outer face (50O) greater in the pre-loaded shape than in the at-rest shape.